Which Supplements Actually Work? An Evidence Review
Updated: 1 day ago
The short answer
For healthy, well-fed adults, most popular supplements do little or nothing to prevent heart disease, cancer, or early death, and a few carry real harm. The clear wins are narrow: fish oil helps most if you rarely eat fish, and correcting a proven deficiency in vitamin D, B12, or iron genuinely helps. Beta-carotene, high-dose vitamin E, high-dose vitamin A, and niacin taken with a statin belong on the stop list, not the shelf. The honest rule is food first, and a pill only to fix a gap a blood test has actually found. There is no single king supplement. There is a short list that helps, a long list that does nothing, and a real list that can hurt you.
What we cover
The 2022 US Preventive Services Task Force review of 84 trials and more than 739,000 people that found little or no prevention benefit (JAMA, 2022)
Fish oil in the VITAL randomized trial, where total heart attacks fell about 28 percent, with the biggest benefit in people who rarely eat fish (New England Journal of Medicine, 2019)
When fixing a real deficiency in vitamin D, B12, or iron helps, and why B12 runs low in older and mostly plant-based eaters
Why routine multivitamins and high-dose vitamin D show no prevention benefit for well-nourished people (Journal of the American College of Cardiology, 2021)
The stop list with possible harm: beta-carotene and lung cancer risk in smokers, high-dose vitamin E, high-dose vitamin A, and niacin taken with a statin
Why calcium plus vitamin D together showed a possible rise in stroke risk (Annals of Internal Medicine, 2019)
Where alpha-lipoic acid actually fits, and how to shop the pharmacy aisle without getting sold
Timestamps
00:00 Which supplements actually work
01:00 84 trials and 739,000 people
02:11 Supplements worth taking
03:25 Supplements that are a waste of money
04:15 Supplements to stop taking
05:57 Is alpha-lipoic acid the new king
06:57 How to be a smart supplement buyer
07:58 Check your cabinet tonight
References
US Preventive Services Task Force recommendation on vitamin and mineral supplements for preventing heart disease and cancer. Evidence review and guideline. JAMA, 2022.
VITAL, a randomized trial of marine omega-3 fatty acids in nearly 26,000 adults. Randomized trial. New England Journal of Medicine, 2019.
JACC Focus Seminar on supplemental vitamins and minerals for cardiovascular disease. Systematic review and meta-analysis. Journal of the American College of Cardiology, 2021.
Umbrella review of nutritional supplements and dietary interventions on cardiovascular outcomes. Umbrella review of randomized trials. Annals of Internal Medicine, 2019.
When to see a doctor
If you have kidney disease or take prescription medications, review any supplement with your own doctor before you start it, because some can raise potassium or phosphorus or interact with your prescriptions. Get tested first, so any supplement you take is fixing a gap a lab has confirmed rather than one you are only hoping to close.
Want the evidence without the hype? Get my free metabolic health guide at guides.selfprinciple.org/metabolic.
This content is for educational purposes only and is not medical advice. Always consult your healthcare provider for individual care. The views expressed are Dr. Sean Hashmi's own and do not represent his employer.
Never start, stop, or change the dose of any prescription medication without consulting your physician.
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