Supplement Research Guides
Read claim-specific research summaries and safety cautions. Results from a study do not establish that a supplement treats every related condition or is suitable for you.
Articles have not all received independent clinical or statistical review. We do not claim firsthand product testing or independently reproduced original meta-analyses. Learn about our editorial process and rating limitations, or browse supplement articles.
Supplements We've Rated
Collagen
Joint pain evidence is solid. Skin benefits look good until you remove industry-funded studies. Gut health claims have …
Creatine
Strong evidence for strength and muscle mass from massive meta-analyses. Emerging evidence for cognition, especially in …
Curcumin
Strong evidence for lowering inflammation markers and relieving joint pain. Comparable to NSAIDs for osteoarthritis with …
Magnesium
Strong evidence for small blood pressure reductions. Modest evidence for sleep. Suggestive for anxiety. Doesn't prevent …
Melatonin
Strong evidence for faster sleep onset and jet lag prevention. Modest evidence for sleep quality. Low doses (0.5-3mg) …
Omega-3 / Fish Oil
Strong evidence for reducing heart disease risk, triglycerides, and inflammation. Moderate evidence for depression, but …
Probiotics
Strong evidence for IBS symptoms across 72+ RCTs. Proven for AAD and C. difficile prevention. Cochrane-backed for …
Vitamin D
Strong evidence for immune function, respiratory infections, and fall prevention at 800-1000 IU daily. Daily dosing may …
Zinc
Strong evidence for immune function and shortening colds. Moderate evidence for acne, especially topical. No real …
Ashwagandha
Some preparations may help stress and insomnia; NCCIH says evidence for anxiety is unclear. Safety, preparation and the …