Many over-the-counter products are available for relief of musculoskeletal pain. Some are based on “dietary ingredients”—substances the Food and Drug Administration (FDA) has accepted for use in foods or dietary supplements. Such products are available in the form of capsules, tablets, powders, liquids, topical creams, and patches. The first 4 potentially qualify as dietary supplements, which (by definition) must be taken by mouth; the last 2 do not. How well do they work? Researchers at the Consortium for Health and Military Performance (CHAMP) at the Uniformed Services University recently conducted an in-depth search of the scientific literature to gather all the reliable evidence together into a resource to help you make informed choices when considering non-drug products for musculoskeletal pain.
Below are lists of ingredients grouped according to whether they have sufficient reliable evidence of possible effectiveness, lack such evidence, or have evidence showing that undesirable effects outweigh any possible benefit with regard to relieving musculoskeletal pain. Some of these ingredients do have potential benefits for other uses, so it’s important to keep in mind that this discussion is limited to the effects on musculoskeletal pain.
What’s the evidence?
A diverse group of experts, both military and civilian, with expertise in human performance, dietary supplements, nutrition, and pain reviewed the results of CHAMP’s evaluation of the literature and developed evidence-based recommendations for the Special Operations community. The results, summarized here, are also useful for Warfighters in general. The study was sponsored by the U.S. Special Operations Command’s Preservation of the Force and Family Behavioral Health Program (POTFF).
Possibly effective dietary ingredients
The following dietary ingredients might help alleviate musculoskeletal pain with little to no risk of any harmful side effects (adverse events). Some can be taken as part of a balanced diet, others as a dietary supplement, and some as a topical (cream, patch) application. Note: They should be used only after consulting a healthcare provider.
- Avocado soybean unsaponifiables (ASU) are made from one-third avocado oil and two-thirds soybean oil. ASU might reduce pain and improve function for some users. Studies have used 300–600 mg per day of ASU for 3 months to 3 years, although this is based on research with a single commercial product. Reported side effects include minor gastrointestinal complaints.
- Capsaicin is a primary constituent of the Capsicum species of chili peppers. Capsicum is grown worldwide and adds color, pungency (“heat”), and aroma to food. Studies have reported significant pain reduction within 4 weeks from using a capsaicin cream applied to the skin. Most creams contain 0.025–0.075% capsaicin and can be applied 3 or 4 times a day. Some users report burning, itching, and irritation, especially when used at higher doses such as 0.25%. Initial use should begin at a lower dose.
- Curcuma, or turmeric, is a spice that comes from a plant grown throughout India, other parts of Asia, and Central America. Turmeric root and powder are available as grocery items for cooking. Research studies using doses of 700–2,000 mg per day over 6–12 weeks have shown significant pain reduction. The only reported side effects are minor gastrointestinal complaints. Insufficient evidence exists for its effectiveness as a dietary supplement, but 500 mg 2 or 3 times a day can be incorporated into cooking.
- Ginger is a tropical plant widely used as a flavoring or fragrance in foods, beverages, soaps, and cosmetics. Common forms include fresh or dried root, tablets, capsules, liquid extracts, and teas. As a dietary supplement, it doesn’t appear to be as effective as other ingredients listed here, but it poses no additional risk when used in food or tea to help with pain. Minor complaints of bad taste or stomach upset have been reported. In research, doses of 250–1,000 mg per day over 3–12 weeks have been used, with higher doses producing greater benefits. As with curcumin, it can be incorporated into cooking.
- Glucosamine is produced naturally in the human body, but it is also available in prescription and over-the-counter products. The most effective form to reduce pain seems to be crystalline glucosamine sulfate (pCGS) at a dose of 1500 mg per day. Little reliable evidence is available for over-the-counter versions, for which dosing and formulas vary. Side effects of 1,500 mg pCGS include nausea, heartburn, diarrhea, constipation, drowsiness, skin reaction, and headache. Effectiveness and tolerance are similar to 1200 mg per day Ibuprofen, but pCGS takes longer to be effective. (The effectiveness of pCGS combined with prescription chondroitin is still unknown. Controversy concerning the use of glucosamine sulfate and combination products containing glucosamine largely reflects the differing regulatory status, labeling, and availability of medications in different regions of the world.)
- Melatonin is produced by the pineal gland and plays a role in sleep, with production and release related to time of day (that is, rising in the evening and falling in the morning). It is available as both prescription and over-the-counter sleep aids. However, the research into its use to relieve musculoskeletal pain is very limited. Studies have used 3–10 mg per day over 4–8 weeks, but lower doses of 3–5 mg per day are preferred until better evidence is available. Side effects are uncommon but include drowsiness, nausea, and headache.
- Polyunsaturated fatty acids (PUFA): Fish oil comes from a variety of fish that provide PUFAs known as omega-3 fatty acids, (alpha-linolenic acid [ALA], eicosapentaenoic acid [EPA], and docosahexaenoic acid [DHA]). Fish oil supplements contain varying amounts of EPA and DHA (18–51% and 12–32%, respectively). ALA is mainly found in green vegetables, canola oil, and soybeans. EPA and DHA almost exclusively come from fish oil and other seafoods. Omega-3 fatty acids might help relieve pain. Studies have used various combinations and doses of PUFAs (300–9,600 mg per day over 4–48 weeks). Reported side effects include fishy aftertaste, gastrointestinal complaints, and rash. Since PUFAs are already available in food, it should be considered as a dietary source. As a supplement, one should not to exceed 1200 mg per day until we have a better understanding of the various formulations.
- Vitamin D is a fat-soluble vitamin that can be obtained from sun exposure, food, and dietary supplements. Vitamin D promotes calcium absorption, is necessary for bone growth, and appears to affect skeletal muscle, immune regulation, cardiovascular health, and metabolic activities. However, some limited evidence suggests it can help reduce musculoskeletal pain when used in doses of 2,000 IU per day (but not over 4,000 IU per day). Higher doses should be used only as prescribed by a healthcare provider, since excess use can lead to vitamin D toxicity. In research studies, it has been used safely up to 2 years.
Other dietary ingredients have been marketed to reduce musculoskeletal pain, but some lack sufficient reliable evidence of effectiveness or information enabling us to weigh the desirable against undesirable effects. Among these are:
- Devil’s claw
- Methylsulfonylmethane (MSM)
- Rose hip
- Vitamin E
- Willow bark extract
Keep in mind that the above applies only to the use of these ingredients to relieve musculoskeletal pain. At least some of them are possibly effective for other uses.
When you’re considering products or ingredients to help relieve your musculoskeletal pain, remember: