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Nutritional Supplement

L-Tryptophan

Also indexed as:Tryptophan

  • Negative Interactions

    19

    • L-Tryptophan

      Almotriptan

      Potential Negative Interaction

      Triptans work by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with eletriptan could increase eletriptan-induced side effects. However, no interactions have yet been reported with eletriptan and 5-HTP or L-tryptophan.

    • L-Tryptophan

      Citalopram

      Potential Negative Interaction

      Citalopram increases serotonin activity in the brain. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking either of these compounds with citalopram may increase citalopram-induced side effects. Dietary supplements of L-tryptophan (available only by prescription from special compounding pharmacists) taken with paroxetine (a drug that has similar actions as citalopram) caused headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms.

      Some doctors have used small amounts of L-tryptophan in combination with SSRIs, to increase their effectiveness. However, because of the potential for side effects, 5-HTP and L-tryptophan should never be taken in combination with citalopram or other SSRIs, unless a doctor is closely monitoring the combination. Foods rich in L-tryptophan do not appear to interact with citalopram or other SSRIs.

      Citalopram
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, 1997.

    • L-Tryptophan

      Eletriptan

      Potential Negative Interaction

      Eletriptan works by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with eletriptan could increase eletriptan-induced side effects. However, no interactions have yet been reported with eletriptan and 5-HTP or L-tryptophan.

    • L-Tryptophan

      Escitalopram

      Potential Negative Interaction

      Escitalopram increases serotonin activity in the brain. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking either of these compounds with escitalopram may increase escitalopram-induced side effects. Dietary supplements of L-tryptophan (available only by prescription from special compounding pharmacists) taken with paroxetine (a drug that has similar actions as escitalopram) caused headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms.

      Some doctors have used small amounts of L-tryptophan in combination with SSRIs, to increase their effectiveness. However, because of the potential for side effects, 5-HTP and L-tryptophan should never be taken in combination with escitalopram or other SSRIs, unless a doctor is closely monitoring the combination. Foods rich in L-tryptophan do not appear to interact with escitalopram or other SSRIs.

      Escitalopram
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, 1997.

    • L-Tryptophan

      Fluoxetine

      Potential Negative Interaction

      L-tryptophan is an amino acid found in protein-rich foods. Foods rich in L-tryptophan are not believed to cause any problems during fluoxetine use. However, dietary supplements of L-tryptophan taken during fluoxetine treatment have been reported to cause headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms.

      Fluoxetine
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1997, 264r-4s.

    • L-Tryptophan

      Fluvoxamine

      Potential Negative Interaction

      Fluvoxamine works by increasing serotonin activity in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with fluvoxamine may increase fluvoxamine-induced side effects. Until more is known, 5-HTP and L-tryptophan should not be taken with any SSRI drug, including fluvoxamine.

    • L-Tryptophan

      Frovatriptan

      Potential Negative Interaction

      Triptans work by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them at the same time as 5-HT1 agonists could increase unwanted side effects. However, at the time of this writing there are no known interactions with 5-HT1 agonists and 5-HTP or L-tryptophan.

      Frovatriptan
      L-Tryptophan
      ×
      1. Wolters Kluwer Health, Inc. Facts and Comparisons [online] 2007 [cited 2007 Feb]. Available from http://www.factsandcomparisons.com.

    • L-Tryptophan

      Olanzapine-Fluoxetine

      Potential Negative Interaction

      This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.

      Triptans work by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them at the same time as 5-HT1 agonists could increase unwanted side effects. However, at the time of this writing there are no known interactions with 5-HT1 agonists and 5-HTP or L-tryptophan.

      Olanzapine-Fluoxetine
      L-Tryptophan
      ×
      1. Wolters Kluwer Health, Inc. Facts and Comparisons [online] 2007 [cited 2007 Feb]. Available from http://www.factsandcomparisons.com.

    • L-Tryptophan

      Paroxetine

      Potential Negative Interaction

      Paroxetine increases serotonin activity in the brain. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking either of these compounds with paroxetine may increase paroxetine-induced side effects. Dietary supplements of L-tryptophan (available only by prescriptions from special compounding pharmacists) taken with paroxetine caused headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms. Some doctors have used small amounts of L-tryptophan in combination with SSRIs, to increase the effectiveness of the latter. However, because of the potential for side effects, 5-HTP and L-tryptophan should never be taken in combination with paroxetine or other SSRIs, unless the combination is being closely monitored by a doctor. Foods rich in L-tryptophan do not appear to interact with paroxtine or other SSRIs.

      On the other hand, the combination of 45 mg DL-tryptophan (a synthetic variation of L-tryptophan) per pound of body weight (a relatively high dose) with zimelidine, a drug with a similar action to paroxetine, did not cause these side effects in another trial.

      Paroxetine
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1997, 264q-4r.
      2. Walinder J, Carlsson A, Persson R. 5-HT reuptake inhibitors plus tryptophan in endogenous depression. Acta Psych Scand Suppl 1981;290:179-90.

    • L-Tryptophan

      Paroxetine Mesylate

      Potential Negative Interaction

      This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.

      Sertraline increases serotonin activity in the brain. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking either of these compounds with sertraline may increase sertraline-induced side effects.

      In one report, dietary supplements of L-tryptophan (available only by prescriptions from special compounding pharmacists) taken with paroxetine (a drug similar to sertraline) caused headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms. On the other hand, the combination of 45 mg DL-tryptophan (a synthetic variation of L-tryptophan) per pound of body weight (a relatively high dose) with zimelidine, a drug with a similar action to sertraline, did not cause these side effects in another trial. Some doctors have used small amounts of L-tryptophan in combination with SSRIs, to increase the effectiveness of the latter. However, because of the potential for side effects, 5-HTP and L-tryptophan should never be taken in combination with sertraline or other SSRIs, unless the combination is being closely monitored by a doctor. Foods rich in L-tryptophan do not appear to interact with sertraline or other SSRIs.

      Paroxetine Mesylate
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1997, 264q-4r.
      2. Walinder J, Carlsson A, Persson R. 5-HT reuptake inhibitors plus tryptophan in endogenous depression. Acta Psych Scand Suppl 1981;290:179-90.

    • L-Tryptophan

      Rizatriptan

      Potential Negative Interaction

      Triptans work by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them at the same time as 5-HT1 agonists could increase unwanted side effects. However, at the time of this writing there are no known interactions with 5-HT1 agonists and 5-HTP or L-tryptophan.

      Rizatriptan
      L-Tryptophan
      ×
      1. Wolters Kluwer Health, Inc. Facts and Comparisons [online] 2007 [cited 2007 Feb]. Available from http://www.factsandcomparisons.com.

    • L-Tryptophan

      Sertraline

      Potential Negative Interaction

      This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.

      Sertraline increases serotonin activity in the brain. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking either of these compounds with sertraline may increase sertraline-induced side effects.

      In one report, dietary supplements of L-tryptophan (available only by prescriptions from special compounding pharmacists) taken with paroxetine (a drug similar to sertraline) caused headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms. On the other hand, the combination of 45 mg DL-tryptophan (a synthetic variation of L-tryptophan) per pound of body weight (a relatively high dose) with zimelidine, a drug with a similar action to sertraline, did not cause these side effects in another trial. Some doctors have used small amounts of L-tryptophan in combination with SSRIs, to increase the effectiveness of the latter. However, because of the potential for side effects, 5-HTP and L-tryptophan should never be taken in combination with sertraline or other SSRIs, unless the combination is being closely monitored by a doctor. Foods rich in L-tryptophan do not appear to interact with sertraline or other SSRIs.

      Sertraline
      L-Tryptophan
      ×
      1. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1997, 264q-4r.
      2. Walinder J, Carlsson A, Persson R. 5-HT reuptake inhibitors plus tryptophan in endogenous depression. Acta Psych Scand Suppl 1981;290:179-90.

    • L-Tryptophan

      Sibutramine

      Potential Negative Interaction

      The amino acids L-tryptophan and 5-hydroxytryptophan (5-HTP) are occasionally used to treat mental depression. Taking sibutramine with L-tryptophan or 5-HTP might result in a rare, but serious group of symptoms known as “serotonin syndrome.” Symptoms associated with serotonin syndrome may include confusion, anxiety, muscle weakness, incoordination, and vomiting. Therefore, individuals taking sibutramine should avoid supplementing with L-tryptophan and 5-HTP.

      Sibutramine
      L-Tryptophan
      ×
      1. Sifton DW, et. Physicians' Desk Reference. Montvale, NJ: Medical Economics Company, Inc. 2000, 1509-13.

    • L-Tryptophan

      Sumatriptan

      Potential Negative Interaction

      This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.

      Sumatriptan works by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with sumatriptan could increase sumatriptan-induced side effects. However, no interactions have yet been reported with sumatriptan and 5-HTP or L-tryptophan.

    • L-Tryptophan

      Sumatriptan Succinate

      Potential Negative Interaction

      This interaction is based on this drug belonging to a drug class. While this drug may differ from the text and references below, drugs within this class work in a similar way and this interaction is applicable to drugs within the same class.

      Sumatriptan works by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with sumatriptan could increase sumatriptan-induced side effects. However, no interactions have yet been reported with sumatriptan and 5-HTP or L-tryptophan.

    • L-Tryptophan

      Tramadol

      Potential Negative Interaction

      Tramadol, which blocks serotonin reuptake in the brain, has been associated with two cases of serotonin syndrome. 5-HTP and L-tryptophan are converted to serotonin in the brain. While no interactions have yet been reported with tramadol and 5-HTP or L-tryptophan, taking 5-HTP or L-tryptophan with tramadol may increase the risk of tramadol-induced side effects, including serotonin syndrome.

      Tramadol
      L-Tryptophan
      ×
      1. Mason BJ, Blackburn KH. Possible serotonin syndrome associated with tramadol and sertraline coadministration. Ann Pharmacother 1997;31:175-7.
      2. Hernandez AF, Montero MN, Pla A, Villanueva E. Fatal moclobemide overdose or death caused by serotonin syndrome? J Forensic Sci 1995;40:128-30.

    • L-Tryptophan

      Venlafaxine

      Potential Negative Interaction

      Venlafaxine, a potent serotonin reuptake inhibitor, has been associated with several cases of serotonin syndrome. 5-HTP and L-tryptophan are converted to serotonin in the brain, and taking them with venlafaxine may increase venlafaxine-induced side effects. While no interactions with venlafaxine and 5-HTP or L-tryptophan have been reported, until more is known, people taking venlafaxine are cautioned to avoid 5-HTP or L-tryptophan.

      Venlafaxine
      L-Tryptophan
      ×
      1. Brubacher JR, Hoffman RS, Lurin MJ. Serotonin syndrome from venlafaxine-tranylcypromine interaction. Vet Hum Toxicol 1996;38:358-61.
      2. Weiner LA, Smythe M, Cisek J. Serotonin syndrome secondary to phenelzine-venlafaxine interaction. Pharmacotherapy 1998;18:399-403.
      3. Bhatara VS, Magnus RD, Paul KL, Preskorn SH. Serotonin syndrome induced by venlafaxine and fluoxetine: a case study in polypharmacy and potential pharmacodynamic and pharmacokinetic mechanisms. Ann Pharmacother 1998;32:432-6.
      4. Diamond S, Pepper BJ, Diamond ML, et al. Serotonin syndrome induced by transitioning from phenelzine to venlafaxine: four patient reports. Neurology 1998;51:274-6.

    • L-Tryptophan

      Zolmitriptan

      Potential Negative Interaction

      Zolmitriptan works by stimulating serotonin receptors in the brain. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with zolmitriptan could increase zolmitriptan-induced side effects. However, no interactions have yet been reported with zolmitriptan and 5-HTP or L-tryptophan.

    • L-Tryptophan

      Zolpidem

      Potential Negative Interaction

      Nine cases of zolpidem-induced hallucinations associated with serotonin reuptake inhibiting antidepressants have been reported, some lasting for several hours. 5-HTP (5-Hydroxytryptophan) and L-tryptophan are converted to serotonin in the brain, and taking them with zolpidem may increase zolpidem-induced hallucinations, though no interactions have yet been reported with zolpidem and 5-HTP or L-tryptophan.

      Zolpidem
      L-Tryptophan
      ×
      1. Elko CJ, Burgess JL, Robertson WO. Zolpidem-associated hallucinations and serotonin reuptake inhibition: a possible interaction. J Toxicol Clin Toxicol 1998;36:195-203.

  • Supportive Interactions

    15

    • L-Tryptophan

      Clozapine

      Replenish Depleted Nutrients

      Some people who take clozapine become mentally depressed after taking the drug for a few weeks. Studies have shown that clozapine can reduce blood levels of the amino acid L-tryptophan, which is often deficient in people with depression. More controlled research is needed to determine whether the interaction is significant and whether individuals taking clozapine might benefit from supplemental L-tryptophan or 5-hydroxytryptophan (5-HTP).

      Clozapine
      L-Tryptophan
      ×
      1. Meltzer HY. Clinical studies on the mechanism of action of clozapine: the dopamine-serotonin hypothesis of schizophrenia. Psychopharmacology 1989;99 Suppl:S18-27 (Berlin).

    • L-Tryptophan

      Diclofenac

      Replenish Depleted Nutrients

      Diclofenac causes complex changes to L-tryptophan levels in the blood, but the clinical implications of this are unknown. More research is needed to determine whether supplementation with L-tryptophan is a good idea for people taking diclofenac.

      Diclofenac
      L-Tryptophan
      ×
      1. Davies NM, Anderson KE. Clinical pharmacokinetics of diclofenac. Therapeutic insights and pitfalls. Clin Pharmacokinet 1997;33:184-213.

    • L-Tryptophan

      Allopurinol

      Support Medicine

      In a preliminary study, seven of eight individuals with severe mental depression showed improvement when they took L-tryptophan and allopurinol; of these seven, five experienced full remission. Controlled research is necessary to determine whether this combination might be more effective for severe depression than standard treatment.

      Allopurinol
      L-Tryptophan
      ×
      1. Stern SL, Mendels J. Drug combinations in the treatment of refractory depression: a review. J Clin Psychiatry 1981;42:368-73.

    • L-Tryptophan and Vitamin B3

      Amitriptyline

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Amitriptyline
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan and Vitamin B3

      Amoxapine

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Amoxapine
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan and Vitamin B3

      Benztropine

      Support Medicine

      Akathisia is an adverse reaction to anti-psychotic drugs, where a person has an uncontrollable desire to be in constant motion. One preliminary report suggested that 4,000 mg of L-tryptophan and 25 mg niacin per day taken with benztropine enhances the treatment of akathisia. Controlled studies are necessary to determine whether L-tryptophan and niacin supplements might benefit most people taking benztropine who experience adverse reactions to anti-psychotic drugs.

      Benztropine
      L-Tryptophan and Vitamin B3
      ×
      1. Kramer MS, DiJohnson C, Davis P, et al. L-tryptophan in neuroleptic-induced akathisia. Biol Psychiatry 1990;27:671-2.

    • L-Tryptophan and Vitamin B3

      Clomipramine

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Clomipramine
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan

      Desipramine

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Desipramine
      L-Tryptophan
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan and Vitamin B3

      Doxepin

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Doxepin
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan and Vitamin B3

      Imipramine

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Imipramine
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan

      Lithium

      Support Medicine

      A small double-blind study found that combining 2–4 grams three times per day of L-tryptophan with lithium significantly improved symptoms in people with bipolar disorder or a mild form of schizophrenia. L-tryptophan is only available from doctors. It should be taken several hours before or after meals.

      Lithium
      L-Tryptophan
      ×
      1. Brewerton TD, Reus VI. Lithium carbonate and L-tryptophan in the treatment of bipolar and schizoaffective disorders. Am J Psychiatry 1983;140:757-60.

    • L-Tryptophan and Vitamin B3

      Nortriptyline

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Nortriptyline
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan and Vitamin B3

      Protriptyline

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Protriptyline
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

    • L-Tryptophan

      Selegiline

      Support Medicine

      Both L-tryptophan and 5-HTP have been used to treat depression. One controlled study showed that taking selegiline at the same time as 5-HTP enhanced the antidepressant effect when compared with 5-HTP alone. Further research is needed to determine whether taking selegiline and 5-HTP together might result in unwanted side effects.

      Selegiline
      L-Tryptophan
      ×
      1. Mendlewicz J, Youdim MB. Antidepressant potentiation of 5-hydroxytryptophan by L-deprenil in affective illness. J Affect Disord 1980;2:137-46.

    • L-Tryptophan and Vitamin B3

      Trimipramine

      Support Medicine

      Combination of 6 grams per day L-tryptophan and 1,500 mg per day niacinamide (a form of vitamin B3) with imipramine has shown to be more effective than imipramine alone for people with bipolar disorder. These levels did not improve the effects of imipramine in people with depression. Lower amounts (4 grams per day of L-tryptophan and 1,000 mg per day of niacinamide) did show some tendency to enhance the effect of imipramine.

      The importance of the amount of L-tryptophan was confirmed in other studies, suggesting that if too much L-tryptophan (6 grams per day) is used, it is not beneficial, while levels around 4 grams per day may make tricyclic antidepressants work better.

      Trimipramine
      L-Tryptophan and Vitamin B3
      ×
      1. Chouinard G, Young SN, Annable L, Sourkes TL. Tryptophan-nicotinamide, imipramine and their combination in depression. Acta Psychiatr Scand 1979;59:395-414.
      2. Walinder J, Skott A, Carlsson A, et al. Potentiation of the antidepressant action of clomipramine by tryptophan. Arch Gen Psychiatry 1976;33:1384-9.
      3. Shaw DM, MacSweeney DA, Hewland R, Johnson AL. Tricyclic antidepressants and tryptophan in unipolar depression. Psychol Med 1975;5:276-8.

  • Explanation Required

    1

    • L-Tryptophan

      Clorazepate

      Needs Explanation

      Test tube studies show that L-tryptophan and clorazepate dipotassium interact in the blood in such a way that the actions of the drug may be enhanced when high amounts of L-tryptophan are ingested. Controlled research is needed to determine the significance of this interaction and to investigate possible interactions between clorazepate and 5-hydroxytryptophan, a supplement related to L-tryptophan.

      Clorazepate
      L-Tryptophan
      ×
      1. Coassolo P, Briand C, Bourdeaux M, Sari JC. Microcalorimetric method to determine competitive binding. Action of a psychotropic drug (dipotassium clorazepate) on L-tryptophan human serum albumin complex. Biochem Biophys Acta 1978;538:512-20.

References

1. Guyton AC, Hall JE. Textbook of Medical Physiology, 9th ed. Philadelphia: W. B. Saunders, 1996.

2. Haze JJ. Toward an understanding of the rationale for the use of dietary supplementation for chronic pain management: the serotonin model. Cranio 1991;9:339-43.

3. Leiberman HR, Corkin S, Spring RJ, et al. Mood, performance and pain sensitivity: changes induced by food constituents. J Psychiatr Res 1982;17:135-45.

4. Shpeen SE, Morse DR, Furst ML. The effect of tryptophan on post-operative endodontic pain. Oral Surg Oral Med Oral Pathol 1984;58: 446-9.

5. Ekblom A, Hansson P, Thomsson M. L-tryptophan supplementation does not affect postoperative pain intensity or consumption of analgesics. Pain 1991;44:249-54.

6. Ceccherelli F, Diani MM, Altafini L, et al. Postoperative pain treated by intravenous L-tryptophan: a double-blind study versus placebo in cholecystectomized patients. Pain 1991;47:163-72.

7. Seltzer S, Stoch R, Marcus R, Jackson E. Alteration of human pain thresholds by nutritional manipulation and L-tryptophan supplementation. Pain 1982;13:385-93.

8. Mitchell MJ, Daines GE, Thomas BL. Effect of L-tryptophan and phenylalanine on burning pain threshold. Phys Ther 1987;67:203-5.

9. Seltzer S, Dewart D, Pollack RL, Jackson E. The effects of dietary tryptophan on chronic maxillofacial pain and experimental pain tolerance. J Psychiatr Res 1982-1983;17:181-6.

10. Brady JP, Cheatle MD, Ball WA. A trial of L-tryptophan in chronic pain syndrome. Clin J Pain 1987;3:39-43.

11. Stockstill JW, McCall WD Jr, Gross AJ, Piniewski B. The effect of L-tryptophan supplementation and dietary instruction on chronic myofascial pain. J Am Dent Assoc 1989;118:457-60.

12. Kimball RW, Friedman AP, Vallejo E. Effect of serotonin in migraine patients. Neurology 1960;10:107-11.

13. Poloni M, Nappi G, Arrigo A, Savoldi F. Cerebrospinal fluid 5-hydroxyindoleacetic acid level in migrainous patients during spontaneous attacks, during headache-free periods and following treatment with L-tryptophan. Experientia 1974;30:640-1.

14. Kangasniemi P, Falck B, Langvik V-A, Hyyppa MT. Levotryptophan treatment in migraine. Headache 1978;18:161-6.

15. Sicuteri F. The ingestion of serotonin precursors (L-5-hydroxytryptophan and L-tryptophan) improves migraine headache. Headache 1973;13:19-22.

16. Titus F, Davalos A, Alom J, Codina A. 5-hydroxytryptophan versus methysergide in the prophylaxis of migraine. Eur Neurol 1986;25:327-9.

17. Maissen CP, Ludin HP. Comparison of the effect of 5-hydroxytryptophan and propranolol in the interval treatment of migraine. Schweizerische Medizinische Wochenschrift /Journal Suisse de Medecine 1991;121:1585-90 [in German].

18. De Benedittis G, Massei R. 5-HT precursors in migraine prophylaxis: A double-blind cross-over study with L-5-hydroxytryptophan versus placebo. Clin J Pain 1986;3:123-9.

19. Mathew NT. 5-hydroxytryptophan in the prophylaxis of migraine. Headache 1978;18:111-3.

20. Bono G, Criscuoli M, Martignoni E, et al. Serotonin precursors in migraine prophylaxis. Advances in Neurology 1982;33:357-63.

21. De Giorgis G, Miletto R, Iannuccelli M, et al. Headache in association with sleep disorders in children: A psychodiagnostic evaluation and controlled clinical study ñ L-5-HTP versus placebo. Drugs Exp Clin Res 1987;13:425-33.

22. Santucci M, Cortelli P, Rossi PG, et al. L-5-Hydroxytryptophan versus placebo in childhood migraine prophylaxis: a double-blind crossover study. Cephalalgia 1986;6:155-7.

23. Fitten LJ, Profita J, Bidder TG. L-tryptophan as a hypnotic in special patients. J Am Geriatr Soc 1985;33:294-7.

24. Schneider-Helmert D, Spinweber CL. Evaluation of L-tryptophan for treatment of insomnia: A review. Psychopharmacology (Berlin) 1986;89(1):1-7.

25. Demisch K, Bauer J, Georgi K, Demisch L. Treatment of severe chronic insomnia with L-tryptophan: results of a double-blind cross-over study. Pharmacopsychiatry. 1987;20:242-4.

26. Hudson C, Hudson SP, Hecht T, MacKenzie J. Protein source tryptophan versus pharmaceutical grade tryptophan as an efficacious treatment for chronic insomnia. Nutr Neurosci 2005;8:121-7.

27. Spinweber C. L-Tryptophan administered to chronic sleep-onset insomniacs: Late-appearing reduction of sleep latency. Psychopharmacology 1986;90:151-5.

28. Spinweber CL, Ursin R, Hilbert RP, Hilderbrand RL. L-tryptophan: effects on daytime sleep latency and the waking EEG. Electroencephalogr Clin Neurophysiol 1983;55:652-61.

29. Hartmann E, Lindsley JG, Spinweber C. Chronic insomnia: effects of tryptophan, flurazepam, secobarbital, and placebo. Psychopharmacology (Berl) 1983;80:138-42.

30. Yogman MW, Zeisel SH. Diet and sleep patterns in newborn infants. N Engl J Med 1983;309:1147-9.

31. Hartmann E. Effects of L-tryptophan on sleepiness and on sleep. J Psychiatr Res 1982-3;17:107-13 [review].

32. Lindsley JG, Hartmann EL, Mitchell W. Selectivity in response to L-tryptophan among insomniac subjects: a preliminary report. Sleep 1983;6:247-56.

33. Fernstrom JD, Faller DV. Neutral amino acids in the brain: Changes in response to food ingestion. J Neurochem 1978;30:1531-8.

34. Puttini PS, Caruso I. Primary fibromyalgia syndrome and 5-hydroxy-L-tryptophan: a 90-day open study. J Int Med Res 1992;20:182-9.

35. Bruni O, Ferri R, Miano S, Verrillo E. L-5-Hydroxytryptophan treatment of sleep terrors in children. Eur J Pediatr 2004;163:402-7.

36. Kimball RW, Friedman AP, Vallejo E. Effect of serotonin in migraine patients. Neurology 1960;10:107-11.

37. Sandyk R. L-tryptophan in neuropsychiatric disorders: a review. Int J Neurosci 1992;67:127-44 [review].

38. Sandyk R. L-Tryptophan in the treatment of restless legs syndrome. Am J Psychiatry 1986;143:554-5.

39. Menkes DB, Coates DC, Fawcett JP. Acute tryptophan depletion aggravates premenstrual syndrome. J Affect Disord 1994;32:37-44.

40. Steinberg S, Annable L, Young SN, Liyanage N. A placebo-controlled clinical trial of L-tryptophan in premenstrual dysphoria. Biol Psychiatry 1999;45:313-20.

41. Steinberg S, Annable L, Young SN, Belanger MC. Tryptophan in the treatment of late luteal phase dysphoric disorder: a pilot study. J Psychiatry Neurosci 1994;19 :114-9.

42. Kaye WH, Weltzin TE. Serotonin activity in anorexia and bulimia nervosa: relationship to the modulation of feeding and mood. J Clin Psychiatry 1991;52 Suppl:41-8 [review].

43. Smith KA, Fairburn CG, Cowen PJ. Symptomatic relapse in bulimia nervosa following acute tryptophan depletion. Arch Gen Psychiatry 1999;56:171-6.

44. Weltzin TE, Fernstrom MH, Fernstrom JD, et al. Acute tryptophan depletion and increased food intake and irritability in bulimia nervosa. Am J Psychiatry 1995;152:1668-71.

45. Oldman AD, Walsh AES, Salkovskis P, et al. Biochemical and behavioural effects of acute tryptophan depletion in abstinent bulimic subjects: a pilot study. Psychol Med 1995;25:995-1001.

46. Anderson IM, Parry-Billings M, Newsholme EA, et al. Dieting reduces plasma tryptophan and alters brain 5-HT function in women. Psychol Med 1990;20:785-91.

47. Mira M, Abraham S. L-tryptophan as an adjunct to treatment of bulimia nervosa. Lancet 1989;ii:1162-3 [letter].

48. Krahn D, Mitchell J. Use of L-tryptophan in treating bulimia. Am J Psychiatry 1985;142:1130 [letter].

49. Brewerton TD, Murphy DL, Jimerson DC. Testmeal responses following m-chlorophenylpiperazine and L-tryptophan in bulimics and controls. Neuropsychopharmacology 1994;11:63-71.

50. Thibault L, Roberge AG. The nutritional status of subjects with anorexia nervosa. Int J Vitam Nutr Res 1987;57:447-52.

51. Abou-Saleh MT, Coppen A. The biology of folate in depression: implications for nutritional hypotheses of the psychoses. J Psychiatr Res 1986;20:91-101 [review].

52. Beaumont PJ, Chambers TL, Rouse L, Abraham SF. The diet composition and nutritional knowledge of patients with anorexia nervosa. J Hum Nutr 1981;35:265-73.

53. Rock CL, Vasantharajan S. Vitamin status of eating disorder patients: relationship to clinical indices and effect of treatment. Int J Eat Disord 1995;18:257-62.

54. Langan SM, Farrell PM. Vitamin E, vitamin A and essential fatty acid status of patients hospitalized for anorexia nervosa. Am J Clin Nutr 1985;41:1054-60.

55. Kaye WH, Weltzin TE. Serotonin activity in anorexia and bulimia nervosa: relationship to the modulation of feeding and mood. J Clin Psychiatry 1991;52 Suppl:41-8 [review].

56. Smith KA, Fairburn CG, Cowen PJ. Symptomatic relapse in bulimia nervosa following acute tryptophan depletion. Arch Gen Psychiatry 1999;56:171-6.

57. Weltzin TE, Fernstrom MH, Fernstrom JD, et al. Acute tryptophan depletion and increased food intake and irritability in bulimia nervosa. Am J Psychiatry 1995;152:1668-71.

58. Oldman AD, Walsh AES, Salkovskis P, et al. Biochemical and behavioural effects of acute tryptophan depletion in abstinent bulimic subjects: a pilot study. Psychol Med 1995;25:995-1001.

59. Anderson IM, Parry-Billings M, Newsholme EA, et al. Dieting reduces plasma tryptophan and alters brain 5-HT function in women. Psychol Med 1990;20:785-91.

60. Mira M, Abraham S. L-tryptophan as an adjunct to treatment of bulimia nervosa. Lancet 1989;ii:1162-3 [letter].

61. Krahn D, Mitchell J. Use of L-tryptophan in treating bulimia. Am J Psychiatry 1985;142:1130 [letter].

62. Brewerton TD, Murphy DL, Jimerson DC. Testmeal responses following m-chlorophenylpiperazine and L-tryptophan in bulimics and controls. Neuropsychopharmacology 1994;11:63-71.

63. Menkes DB, Coates DC, Fawcett JP. Acute tryptophan depletion aggravates premenstrual syndrome. J Affect Disord 1994;32:37-44.

64. Steinberg S, Annable L, Young SN, Liyanage N. A placebo-controlled clinical trial of L-tryptophan in premenstrual dysphoria. Biol Psychiatry 1999;45:313-20.

65. Steinberg S, Annable L, Young SN, Belanger MC. Tryptophan in the treatment of late luteal phase dysphoric disorder: a pilot study. J Psychiatry Neurosci 1994;19 :114-9.

66. Stockmeier CA: Neurobiology of serotonin in depression and suicide. Ann N Y Acad Sci 1997, 836:220-32.

67. Eccleston D. L-tryptophan and depressive illness: a valuable adjunct to therapy? Psychiatric Bulletin 1993;17:223-4 [review].

68. Young SN, Teff KL. Tryptophan availability, 5HT synthesis and 5HT function. Prog Neuropsychopharmacol Biol Psychiat 1989;13:373—9.

69. Werbach MR. Nutritional influences on mental illness, 2nd ed. Tarzana, CA: Third Line Press, 1999, 266-67 [review].

70. Buist R: The therapeutic predictability of tryptophan and tyrosine in the treatment of depression. Int J Clin Nutr Rev 1983;3:1-3 [review].

71. Lindberg D, Ahlfors UG, Dencker SJ, et al. Symptom reduction in depression after treatment with L-tryptophan or imipramine. Item analysis of Hamilton rating scale for depression. Acta Psychiatr Scand 1979;60:287-94.

72. Young SN. The clinical psychopharmacology of tryptophan. In Wurtman RJ, Wurtman JJ, eds. Nutrition and the Brain, Volume 7. New York: Raven Press, 1986, 49-88.

73. Thomson J, Rankin H, Ashcroft GW, et al.The treatment of depression in general practice: a comparison of L-tryptophan, amitriptyline, and a combination of L-tryptophan and amitriptyline with placebo. Psychol Med 1982;12:741-51.

74. Bennie E. Mianserin hydrochloride and Ltryptophan compared in depressive illness. Br J Clin Soc Psych 1982;1:90-1.

75. Jaffe G, Grimshaw J. A placebo-controlled comparison of L-tryptophan and amitriptyline in the treatment of depressive illness in general practice. Br J Clin Soc Psych 1985;3:51-5.

76. Cooper AJ, Datta SR. A placebo controlled evaluation of L-tryptophan in depression in the elderly. Can J Psychiatry 1980;25:386-90.

77. Young SN, Chouinard G, Annable L. Tryptophan in the treatment of depression. Adv Exp Med Biol 1981;133:727-37 [review].

78. Angst J, Woggon B, Schoepf J. The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study. Arch Psychiatr Nervenkr 1977;224:175-86.

79. Nolen WA, van de Putte JJ, Dijken WA, et al. Treatment strategy in depression. II. MAO inhibitors in depression resistant to cyclic antidepressants: two controlled crossover studies with tranylcypromine versus L-5-hydroxytryptophan and nimifensine. Acta Psychiatr Scand 1988;78:676-83.

80. Nolen WA, van de Putte JJ, Dijken WA, Kamp JS. L-5-HTP in depression resistant to re-uptake inhibitors. An open comparative study with tranylcypromine. Br J Psychiatry 1985;147:16-22.

81. D'Elia G, Hanson L, Raotma H. L-tryptophan and 5-hydroxytryptophan in the treatment of depression. A review. Acta Psychiatr Scand 1978;57:239-52 [review].

82. Van Praag HM, Lemus C. Monoamine precursors in the treatment of psychiatric disorders. Nutrition and the Brain, vol. 7, RJ Wurtman, JJ Wurtman, eds. New York: Raven Press, 1986 [review].

83. Van Praag H, de Hann S. Depression vulnerability and 5-hydroxytryptophan prophylaxis. Psychiatry Res 1980;3:75-83.

84. Neumeister A, Konstantinidis A, Praschak-Rieder N, et al. Monoaminergic function in the pathogenesis of seasonal affective disorder. Int J Neuropsychopharmacol 2001;4:409-20.

85. Van der Does AJ. The effects of tryptophan depletion on mood and psychiatric symptoms. J Affect Disord 2001;64:107-19.

86. Levitt AJ, Brown GM, Kennedy SH, Stern K. Tryptophan treatment and melatonin response in a patient with seasonal affective disorder. J Clin Psychopharmacol 1991;11:74-5.

87. Lam RW, Levitan RD, Tam EM, et al. L-tryptophan augmentation of light therapy in patients with seasonal affective disorder. Can J Psychiatry 1997;42:303-6.

88. Ghadirian AM, Murphy BE, Gendron MJ. Efficacy of light versus tryptophan therapy in seasonal affective disorder. J Affect Disord 1998;50:23-7.

89. McGrath RE, Buckwald B, Resnick EV. The effect of L-tryptophan on seasonal affective disorder. J Clin Psychiatry 1990;51:162-3.

90. Birdsall TC. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Alternative Med Rev 1998;3:271-80.

91. Iversen SD. 5-HT and anxiety. Neuropharmacology 1984;23:1553-60 [review].

92. Schruers K, Klaassen T, Pols H, et al. Effects of tryptophan depletion on carbon dioxide provoked panic in panic disorder patients. Psychiatry Res 2000;93:179-87.

93. Argyropoulos SV, Hood SD, Adrover M, et al. Tryptophan depletion reverses the therapeutic effect of selective serotonin reuptake inhibitors in social anxiety disorder. Biol Psychiatry 2004;56:503-9.

94. Hudson C, Hudson S, MacKenzie J. Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot study. Can J Physiol Pharmacol 2007;85:928-32.

95. Zang DX. A self body double blind clinical study of L-tryptophan and placebo in treated neurosis. Zhonghua Shen Jing Jing Shen Ke Za Zhi 1991;24:77-80,123-4 [in Chinese].

96. Galligan JJ. Beneficial actions of microbiota-derived tryptophan metabolites. Neurogastroenterol Motil 2018 02;30(2).

97. Namkung J, Kim H, Park S. Peripheral Serotonin: a New Player in Systemic Energy Homeostasis. Mol Cells 2015 Dec;38(12):1023–8.

98. Strasser B, Berger K, Fuchs D. Effects of a caloric restriction weight loss diet on tryptophan metabolism and inflammatory biomarkers in overweight adults. Eur J Nutr 2015 Feb;54(1):101–7.

99. Hrboticky N, Leiter L, Anderson G. Effects of L-tryptophan on short term food intake in lean men. Nutr Res 1985;5:595–607.

100. Cavaliere H, Medeiros-Neto G. The anorectic effect of increasing doses of L-tryptophan in obese patients. Eat Weight Disord 1997;2:211-5.

101. Strain GW, Strain JJ, Zumoff B. L-tryptophan does not increase weight loss in carbohydrate-craving obese subjects. Int J Obes 1985;9:375-80.

102. Comings DE. Serotonin and the biochemical genetics of alcoholism: lessons from studies of attention deficit hyperactivity disorder (ADHD) and Tourette syndrome. Alcohol Alcohol Suppl 1993;2:237-41 [review].

103. Ferguson HB, Pappas BA, Trites RL, et al. Plasma free and total tryptophan, blood serotonin, and the hyperactivity syndrome: no evidence for the serotonin deficiency hypothesis. Biol Psychiatry. 1981;16:231-8.

104. Stadler C, Zepf FD, Demisch L, et al. Influence of rapid tryptophan depletion on laboratory-provoked aggression in children with ADHD. Neuropsychobiology 2007;56:104-10.

105. Zepf FD, Stadler C, Demisch L, et al. Serotonergic functioning and trait-impulsivity in attention-deficit/hyperactivity-disordered boys (ADHD): influence of rapid tryptophan depletion. Hum Psychopharmacol 2008;23:43-51.

106. Nemzer ED, Arnold LE, Votolato NA, McConnell H. Amino acid supplementation as therapy for attention deficit disorder. J Am Acad Child Psychiatry 1986;25:509-13.

107. Poggiogalle E, Fontana M, Giusti AM, et al. Amino Acids and Hypertension in Adults. Nutrients 2019;11:1459.

108. Feltkamp H, Meurer KA, Godehardt E. Tryptophan-induced lowering of blood pressure and changes of serotonin uptake by platelets in patients with essential hypertension. Klin Wochenschr 1984;62:1115–9.

109. Cade JR, Fregly MJ, Privette M. Effect of tryptophan and 5-hydroxytryptophan on the blood pressure of patients with mild to moderate hypertension. Amino Acids 1992;2:133–42.

110. Young SN. Behavioral effects of dietary neurotransmitter precursors: basic and clinical aspects. Neurosci Biobehav Rev 1996;20:313-23 [review].

111. Riemann D, Vorderholzer U. Treatment of depression and sleep disorders. Significance of serotonin and L-tryptophan in pathophysiology and therapy. Fortschr Med 1998;116:40-2 [review].

112. Chouinard G, Jones BD, Young SN, Annable L. Potentiation of lithium by tryptophan in a patient with bipolar illness. Am J Psychiatry 1979;136:719-20.

113. Hedaya RJ. Pharmacokinetic factors in the clinical use of tryptophan. J Clin Psychopharmacol 1984;4:347-8.

114. Prange AJ, Wilson IC, Lynn CW, et al. L-tryptophan in mania: contribution to a permissive hypothesis of affective disorders. Arch Gen Psychiatry 1974;30:56-62.

115. Chambers CA, Naylor GJ. A controlled trial of L-tryptophan in mania. Br J Psychiatry 1978;132:555-9.

116. Murphy DL, Maker M, Goodwin FK, et al. L-tryptophan in affective disorders: indoleamine changes and differential clinical effects. Psychopharmacologia 1974;34:11-20.

117. van Praag HM, de Haan S. Chemoprophylaxis of depressions. An attempt to compare lithium with 5-hydroxytryptophan. Acta Psychiatr Scand Suppl 1981;290:191-201.

118. Mendlewicz J, Youdim MB. Antidepressant potentiation of 5-hydroxytryptophan by L-deprenil in affective illness. J Affect Disord 1980;2:137-46.

119. Payne IR, Walsh EM, Whittenburg EJ. Relationship of dietary tryptophan and niacin to tryptophan metabolism in schizophrenics and nonschizophrenics. Am J Clin Nutr 1974;27:565-71.

120. Gilmour DG, Manowitz P, Frosch WA, Shopsin B. Association of plasma tryptophan levels with clinical change in female schizophrenic patients. Biol Psychiatry 1973;6:119-28.

121. Morand C, Young SN, Ervin FR. Clinical response of aggressive schizophrenics to oral tryptophan. Biol Psychiatry 1983;18:575-8.

122. Levkovitz Y, Ophir-Shaham O, Bloch Y, et al. Effect of L-tryptophan on memory in patients with schizophrenia. J Nerv Ment Dis 2003;191:568-73.

123. Brewerton TD, Reus VI. Lithium carbonate and L-tryptophan in the treatment of bipolar and schizoaffective disorders. Am J Psychiatry 1983;140:757-60.

124. Gillin JC, Kaplan JA, Wyatt RJ. Clinical effects of tryptophan in chronic schizophrenic patients. Biol Psychiatry 1976;11:635-9.

125. Rosse RB, Schwartz BL, Zlotolow S, et al. Effect of a low-tryptophan diet as an adjuvant to conventional neuroleptic therapy in schizophrenia. Clin Neuropharmacol 1992;15:129-41.

126. Iversen SD. 5-HT and anxiety. Neuropharmacology 1984;23:1553-60 [review].

127. Schruers K, Klaassen T, Pols H, et al. Effects of tryptophan depletion on carbon dioxide provoked panic in panic disorder patients. Psychiatry Res 2000;93:179-87.

128. Argyropoulos SV, Hood SD, Adrover M, et al. Tryptophan depletion reverses the therapeutic effect of selective serotonin reuptake inhibitors in social anxiety disorder. Biol Psychiatry 2004;56:503-9.

129. Hudson C, Hudson S, MacKenzie J. Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot study. Can J Physiol Pharmacol 2007;85:928-32.

130. Zang DX. A self body double blind clinical study of L-tryptophan and placebo in treated neurosis. Zhonghua Shen Jing Jing Shen Ke Za Zhi 1991;24:77-80,123-4 [in Chinese].

131. Hartmann E, Spinweber CL. Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake. J Nerv Ment Dis 1979;167:497-9.

132. Snyder S, Hams G. Serotoninergic agents in the treatment of isolated sleep paralysis. Am J Psychiatry 1982;139:1202-3.

133. Fernstrom JD, Faller DV. Neutral amino acids in the brain: Changes in response to food ingestion. J Neurochem 1978;30:1531-8.

134. Hartmann E, Spinweber CL. Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake. J Nerv Ment Dis 1979;167:497-9.

135. Snyder S, Hams G. Serotoninergic agents in the treatment of isolated sleep paralysis. Am J Psychiatry 1982;139:1202-3.

136. Fernstrom JD, Faller DV. Neutral amino acids in the brain: Changes in response to food ingestion. J Neurochem 1978;30:1531-8.

137. Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev 2002; (1):CD003198.

138. Morgan B, Morgan R. Brainfood: nutrition and your brain. Tucson, Arizona: The Body Press, 1987.

139. Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev 2002; (1):CD003198.

140. Morgan B, Morgan R. Brainfood: nutrition and your brain. Tucson, Arizona: The Body Press, 1987.

141. Blackburn WD. Eosinophilic myalgia syndrome. Semin Arth Rheum 1997;26:788-93.

142. Slutsker L, Hoesly FC, Miller L, et al. Eosinophilia-myalgia syndrome associated with exposure to tryptophan from a single manufacturer. JAMA 1990;264:213-7.

143. Kilbourne EM, Philen RM, Kamb ML, Falk H. Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome. J Rheumatol Suppl 1996;46:81-8.

144. Schlessel K, Greenwald R, Hirschfield L. Scleroderma-like fasciitis without eosinophilia after L-tryptophan ingestion. J Rheumatol 1991;18:779-82.

145. Feroze K, Venkitakrishnan S, Manoj J. L-tryptophan and scleroderma: significance of nutritional supplements containing L-tryptophan. J Postgrad Med 2008;54:235-6.

146. Mensing H. L-tryptophan ingestion does not induce progressive systemic sclerosis (scleroderma). Dermatology 1992;185:173-4.

147. Freundlich B, Werth VP, Rook AH, et al. L-tryptophan ingestion associated with eosinophilic fasciitis but not progressive systemic sclerosis. Ann Intern Med 1990;112:758-62.

148. Devoe LD, Castillo RA, Searle NS, Searle JR. Maternal dietary substrates and human fetal biophysical activity. I. The effects of tryptophan and glucose on fetal breathing movements. Am J Obstet Gynecol 1986;155:135-9.

149. Meier AH, Wilson JM. Tryptophan feeding adversely influences pregnancy. Life Sci 1983;32:1193-6.

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2025.