Three double-blind trials have investigated the effects of supplementing a combination of the enzymes trypsin and chymotrypsin for seven to ten days on severe low back pain with or without accompanying leg pain. Eight tablets per day were given initially in all trials, but in two trials the number of pills was reduced to four per day after two to three days. One of these trials reported small, though statistically significant improvements, for some measures in people with degenerative arthritis of the lower spine.¹⁰ People with sciatica-type leg pain had significant improvement in several measures in one trial,¹¹ while another found the enzymes were not much more effective than a placebo.¹² These trials included chronic low back conditions, so their relevance to acute LBP alone may be limited.

Several animal studies and some research involving humans suggest that a synthetic version of the natural amino acid phenylalanine called D-phenylalaline (DPA), reduces pain by decreasing the enzyme that breaks down endorphins.¹³ It is less clear whether DPA may help people with LBP, though there are a small number of reports to that effect,¹⁴ including one uncontrolled report of 27 of 37 people with LBP experiencing “good to excellent relief.”¹⁵ In a double-blind trial, University of Texas researchers found that 250 mg of DPA four times per day for four weeks was no more effective than placebo for 30 people with various types of chronic pain; 13 of these people had low back pain.¹⁶ In a Japanese clinical trial, 4 grams of DPA per day was given to people with chronic low back pain half an hour before they received acupuncture.¹⁷ Although not statistically significant, the results were good or excellent for 18 of the 30. The most common supplemental form of phenylalanine is D,L-phenylalanine (DLPA). Doctors typically recommend 1,500–2,500 mg per day of DLPA.

A combination of vitamin B1, vitamin B6, and vitamin B12 has proved useful for preventing a relapse of a common type of back pain linked to vertebral syndromes,¹⁸ as well as reducing the amount of anti-inflammatory medications needed to control back pain, according to double-blind trials.¹⁹ Typical amounts used have been 50–100 mg each of vitamins B1 and B6, and 250–500 mcg of vitamin B12, all taken three times per day.^20,21 Such high amounts of vitamin B6 require supervision by a doctor.

Willow bark is traditionally used for pain and conditions of inflammation. According to one controlled clinical trial, use of high amounts of willow bark extract may help people with low back pain. One trial found 240 mg of salicin from a willow extract to be more effective than 120 mg of salicin or a placebo for treating exacerbations of low back pain.²⁵

Proteolytic enzymes, including bromelain, papain, trypsin, and chymotrypsin, may be helpful in healing minor injuries because they have anti-inflammatory activity and are capable of being absorbed from the gastrointestinal tract.^26,27,28 Several preliminary trials have reported reduced pain and swelling, and/or faster healing in people with a variety of conditions who use either bromelain^29,30,31 or papain.^32,33,34

Topical cayenne pepper has been used for centuries to reduce pain, and more recently, to diminish localized pain for a number of conditions,³⁵ including chronic pain,³⁶ although low back pain has not been specifically investigated. Cayenne creams typically contain 0.025–0.075% capsaicin.³⁷ While cayenne cream causes a burning sensation the first few times used, this decreases with each application. Pain relief is also enhanced with use as substance P, the compound that induces pain, is depleted.³⁸ To avoid contamination of the mouth, nose, or eyes, hands should be thoroughly washed after use or gloves should be worn. Do not apply cayenne cream to broken skin.

One double-blind trial found that devil’s claw capsules (containing 800 mg of a concentrated extract taken three times per day) were helpful in reducing acute low back pain in some people.³⁹ Another double-blind trial (using 200 mg or 400 mg of devil’s claw extract three times daily) achieved similar results in some people with exacerbations of chronic low back pain.⁴⁰

Herbalists often use ginger to decrease inflammation and the pain associated with it, including for those with low back pain. They typically suggest 1.5 to 3 ml of ginger tincture three times per day, or 2 to 4 grams of the dried root powder two to three times per day. Some products contain a combination of curcumin and ginger. However, no research has investigated the effects of these herbs on low back pain.

A combination of eucalyptus and peppermint oil applied directly to a painful area may help. Preliminary research indicates that the counter-irritant quality of these essential oils may decrease pain and increase blood flow to afflicted regions.⁴¹ Peppermint and eucalyptus, diluted in an oil base, are usually applied several times per day, or as needed, to control pain. Plant oils that may have similar properties are rosemary, juniper, and wintergreen.

Herbalists often use ginger to decrease inflammation and the pain associated with it, including for those with low back pain. They typically suggest 1.5 to 3 ml of ginger tincture three times per day, or 2 to 4 grams of the dried root powder two to three times per day. Some products contain a combination of curcumin and ginger. However, no research has investigated the effects of these herbs on low back pain.

Several preliminary trials have reported reduced pain and swelling, and/or faster healing in people with a variety of conditions using either bromelain,⁴² papain from papaya, ^43,44 or a combination of trypsin and chymotrypsin.⁴⁵ Double-blind trials have reported faster recovery from athletic injuries, including sprains and strains, and earlier return to activity using eight tablets daily of trypsin/chymotrypsin,^46,47,48,49 four to eight tablets daily of papain,⁵⁰ eight tablets of bromelain (single-blind only),⁵¹ or a combination of these enzymes.⁵² However, one double-blind trial using eight tablets per day of trypsin/chymotrypsin to treat sprained ankles found no significant effect on swelling, bruising, or overall function.⁵³

A combination of eucalyptus and peppermint oil applied directly to a painful area may help. Preliminary research indicates that the counter-irritant quality of these essential oils may decrease pain and increase blood flow to afflicted regions.⁵⁴ Peppermint and eucalyptus, diluted in an oil base, are usually applied several times per day, or as needed, to control pain. Plant oils that may have similar properties are rosemary, juniper, and wintergreen.

Turmeric is another herb known traditionally for its anti-inflammatory effects, a possible advantage for people suffering from low back pain. Several preliminary studies confirm that curcumin, one active ingredient in turmeric, may decrease inflammation in both humans⁵⁵ and animals.^56,57 In one double-blind trial, a formula containing turmeric, other herbs, and zinc significantly diminished pain for people with osteoarthritis.⁵⁸ Standardized extracts containing 400 to 600 mg of curcumin per tablet or capsule are typically taken three times per day. For tinctures of turmeric, 0.5 to 1.5 ml three times per day are the usual amount.

A preliminary report in 1964 suggested that 500–1,000 mg per day of vitamin C helped many people avoid surgery for their disc-related low back pain.⁵⁹ No controlled research has been done to examine this claim further.