| Supplement | Amount | Why |
|---|
Andrographis | 48 to 60 mg andrographolides in two to three divided doses daily |  [3 stars] Andrographis, with its immune system–enhancing actions, has been shown to reduce the severity of the common cold and may prevent the onset of a cold in healthy people. |
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Multivitamin | Follow label directions | [3 stars] Taking a daily multivitamin can help prevent deficiencies that make you a target for infections. |
Vitamin E | 200 IU daily | [3 stars] Vitamin E enhances some measures of immune-cell activity in the elderly. |
|
Ashwagandha | 3 to 6 grams daily of the dried root as tea or in a capsule |  [2 stars] Ashwagandha stimulates the immune system and is considered a tonic or adaptogen—an herb with multiple actions that counteract the effects of stress and generally promote wellness. |
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Asian Ginseng | 100 mg of a standardized extract twice per day | [2 stars] Asian ginseng has a long history of use in traditional herbal medicine for preventing and treating conditions related to the immune system. |
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Beta-Carotene | 25,000 to 100,000 IU per day for nonsmokers only | [2 stars] Beta-carotene has been shown to increase immune cell numbers and activity. It has also been shown to enhance cancer-fighting immune functions in healthy people. |
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Echinacea | 3 to 5 ml of liquid extract three times per day | [2 stars] Studies have found that echinacea stimulates the function of a variety of immune cells, particularly natural killer cells. Taking it appears to speed recovery from the common cold. |
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Eleuthero | 10 ml of tincture three times per day | [2 stars] Eleuthero has historically been used to support the immune system. |
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Glutamine
(Post-Exercise Infection) | Refer to label instructions
| [2 stars] A study giving athletes glutamine, an amino acid important for immune system function, reported significantly fewer infections with glutamine. |
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Probiotics | 10 billion colony-forming units a day of acidophilus or bifidobacteria-only for intestinal infections | [2 stars] Probiotics help stimulate the intestine’s immune system and slow the growth of infectious organisms. |
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Selenium | 100 mcg daily with 20 mg zinc daily | [2 stars] Selenium supplements have been reported to help improve immune function in seniors.
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Thymus Extracts | 1 to 1.5 mg thymus polypeptides per 2.2 lbs body weight | [2 stars] The thymus gland is responsible for many immune system functions. A thymus extract known as Thymomodulin has been shown to improve immune function in some people. |
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Vitamin A | Consult a qualified healthcare practitioner | [2 stars] Vitamin A plays an important role in immune system function and helps mucous membranes, including those in the lungs, resist invasion by microorganisms. |
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Vitamin C | Consult a qualified healthcare practitioner | [2 stars] Vitamin C stimulates the immune system. While taking it has only a small effect in preventing colds, it does significantly reduce the duration of a cold when taken at the onset. |
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Astragalus | Refer to label instructions
|  [1 star] Complex polysaccharides in astragalus affect the immune system. One study showed that astragalus elevate antibody levels in healthy people. |
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Beta-Glucan | Refer to label instructions
| [1 star] Beta-glucan activates white blood cells, which in turn can recognize and kill tumor cells, correct oxidative damage, and speed up recovery of damaged tissue. |
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Cat’s Claw | Refer to label instructions
| [1 star] Substances found in cat’s claw, called oxyindole alkaloids, have been shown to stimulate the immune system. |
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Cordyceps | Refer to label instructions
| [1 star] Cordyceps has immune-strengthening actions and may be helpful in a wide range of conditions in which the immune system is weakened. |
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DHEA | Refer to label instructions
| [1 star] Supplementing with the hormone DHEA may improve immune functioning. |
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Fo-Ti | Refer to label instructions
| [1 star] Preliminary research suggests that fo-ti plays a role in a strong immune system and has antibacterial action. |
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Green Tea | Refer to label instructions
| [1 star] Green tea has stimulated production of immune cells and has shown anti-bacterial properties in some studies. |
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Ligustrum | Refer to label instructions
| [1 star] Ligustrum appears to stimulate the immune system and is often combined with astragalus in traditional Chinese medicine. |
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Lycopene | Refer to label instructions
| [1 star] Large amounts of the carotenoid lycopene have been shown to increase the activity of natural killer cells in the elderly. |
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Maitake | Refer to label instructions
| [1 star] Complex polysaccharides present in maitake appear to increase immune function. |
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Noni | Refer to label instructions
| [1 star] Studies show noni to have some immune-enhancing activity. |
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Vitamin B12 | Refer to label instructions
| [1 star] A deficiency of vitamin B12 has been associated with decreased immune function. Restoring vitamin B12 levels may improve levels of immune cells. |
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Whey Protein | Refer to label instructions
| [1 star] Whey protein appears to improve some aspects of immune function. One trial showed that whey protein increased blood glutathione levels in a group of HIV-infected people. |
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Zinc | 25 mg daily | [1 star] Zinc supplements have been reported to increase immune function. Some doctors recommend zinc supplements for people with recurrent infections. |
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