Evidence reviews of dietary supplements and related health claims.
WhatEvidence.Health claim check Claim checked: taking L-theanine improves stress, anxiety, sleep, and focus. WEH Verdict: Promising, not proven L-theanine may modestly help short-term stress and perceived sleep quality, but it is not proven to treat anxiety disorders, insomnia, ADHD, or poor focus. Claim type Supplement benefit Best evidence Human RCTs and systematic reviews Population General…
Vitamin D is essential. But “essential” does not mean that extra vitamin D prevents every disease. WEH Verdict: Mixed Evidence Supported for deficiency. Not supported as a broad wellness cure-all. Claim type Supplement benefit Best evidence Guidelines, RCTs, meta-analyses Population General readers Last reviewed 10 June 2026 Bottom line Vitamin D is proven to help…
WhatEvidence.Health Claim Check A careful look at the human evidence behind one of longevity medicine’s most popular supplement claims. WEH Verdict: Uncertain NMN can raise NAD+ related markers in humans, but no human trial has shown that NMN or NAD+ supplementation slows aging or extends lifespan. Claim checkedNMN/NAD+ slows aging PopulationAdults Evidence typeHuman RCTs +…
Claim checked: “Omega-3 supplementation with EPA and DHA reduces fasting triglycerides in adults.” WEH Verdict: Supported Yes, for this narrow claim. EPA and DHA reliably lower fasting triglycerides, especially at higher doses and in adults whose triglycerides are already elevated. CategorySupplements Best EvidenceMeta-analyses of RCTs Evidence GradeHigh for triglycerides Last Reviewed31 May 2026 Bottom Line…
Claim checked: “Taking magnesium before bed improves sleep quality, helps you fall asleep faster, and treats insomnia.” C Weak Evidence Possible small benefit, not a sleep cure. The best evidence suggests magnesium may help some people a little, but the effect is modest and the studies are still too small and mixed to call it…
WEH evidence verdict Uncertain as a general claim Probiotics are not one treatment. Some preparations appear useful for specific conditions, while others have failed in large trials. The strain, product, route, population and outcome all matter. The claim being checked Claim: “Probiotics work and are worth taking for common gut and infection-related problems.” This claim…
WhatEvidence.Health · Claim Review Lion’s Mane mushroom improves memory, focus, mood, and overall brain function in humans. C Weak Evidence Plausible and interesting — but not proven. The best human evidence shows small, preliminary signals, mainly in older adults or people with cognitive symptoms. It does not yet prove a reliable “brain boost” for healthy…
PLAUS- IBLE GRADE B EVIDENCE VERDICT Berberine produces real, measurable improvements in blood sugar and cholesterol in people with metabolic disease — backed by dozens of RCTs. Weight-loss effects are modest and do not support the viral “nature’s Ozempic” label. Significant drug interactions and limited long-term safety data require medical supervision before use. At a…
Creatine has real evidence behind it. The benefit is narrower than the online hype suggests. WEH Verdict: Supported for strength and power Good evidence for short-burst performance. Not a general anti-aging or brain-health supplement. Claim type Supplement benefit Best evidence RCTs, meta-analyses, NIH summary Evidence grade Moderate for strength/power Last reviewed 19 June 2026 Bottom…