Do Supplements Actually Work?

Updated July 2026

Vitamins and minerals have long been used to treat genuine nutrient deficiencies. But over the last few decades, supplements have been marketed as a path to better health and longevity for everyone, deficiency or not. It's worked: the global supplement market is now worth well over $150 billion a year and still growing, and more than half of American adults take something. Yet despite all that use, there's still no real agreement that individual vitamins, minerals, or combination supplements do anything to prevent or treat heart disease.

What does the research actually say about supplements?

For heart health, it's largely disappointing. A landmark review of nearly 180 randomized controlled trials looked at whether any common supplement helped, and the four most popular ones — multivitamins, vitamin D, calcium, and vitamin C — showed no consistent benefit for preventing heart disease, heart attack, stroke, or death from any cause. Not even a small benefit that's hard to detect. No consistent benefit at all.

Worse, two were associated with an actual increase in the risk of dying from any cause: niacin (vitamin B3) and antioxidant supplements like vitamin E. This is the part people find hardest to believe, so it's worth sitting with: a supplement isn't automatically harmless just because it's “natural” or “just a vitamin.” Every compound you put in your body has a biological effect.

Is there any supplement that does help?

One, with a big asterisk: folate (folic acid, vitamin B9). In that same body of research, folic acid alone, and B-complex vitamins that included folic acid, showed a reduction in stroke of about 20%. But that signal came from essentially a single study, the China Stroke Primary Prevention Trial, and that matters. Unlike the United States, China does not routinely fortify food with folate. So a folate supplement fills a real gap there in a way it may not for someone already eating a fortified, folate-rich American diet.

So should you take folate?

Probably not as a reflex. Before anyone heads to the warehouse store for a giant bottle of folate pills, remember that the data on food is vast, consistent, and beats supplements handily. Adding 10 grams of whole-food fiber a day, the amount in two servings of Step One Foods, has been shown to cut heart attack risk by 14% and death from any cause by 27%. Adding a single piece of fruit a day lowers stroke risk by 6%. And folate itself is easy to get from food. The recommended 400 mcg a day is well within reach: avocado toast at breakfast, half a cup of lentils in a lunch salad, and some broccoli and hummus in the afternoon gets you most of the way there. Here's where folate actually lives in food:

Reference: NIH Folate Fact Sheet

When do supplements make sense?

When you're correcting a documented deficiency, which is what supplements were designed for in the first place. If a blood test shows you're low in something, treating that is sound medicine. What the evidence argues against is the blanket, just-in-case supplementation that most people are actually doing. Worse yet might be the “bio-hacking” some people are gravitating to, taking massive doses of a compound on the promise that some isolated chemical property of that supplement will have magical effects on a body that is endlessly complex and unique.

Here's how this plays out in my own practice. When patients ask about supplements, my honest answer has long been that the data is underwhelming: they don't seem to help much, probably won't hurt if doses aren't extreme, and I'd rather we focus on food. Two things have sharpened that over the years. I now specifically look for niacin and vitamin E in a patient's supplement list and suggest dropping those, given the mortality signal. And when I review someone's diet, I pay close attention to whether they're getting enough folate from food, and only recommend a supplement for the ones who genuinely aren't.

I'll be honest about my own habits too, since patients always ask. For a while I took vitamin D because a test showed my level was low. It's since come back into the normal range, in part from my making a point of getting outside more, so I no longer take it. That's the whole philosophy in one story: test, treat a real gap if you have one, and lean on food and lifestyle for everything else.

The one truth that keeps proving itself is this: supplements may help fill a specific nutritional gap, but they are no substitute for actual nutrition.

Want to go deeper on a specific supplement?

I've written a closer look at the ones patients ask about most:

• The truth about fish oil supplements
• Should you take a vitamin D supplement?
• Are calcium supplements worth it?
• Do you need antioxidant supplements?
• Supplements for cholesterol lowering? Not so fast.
• Does collagen actually work?
• Creatine: not just for gym bros
• Magnesium and type 2 diabetes
• Does vitamin K2 help with cholesterol or coronary artery calcification?

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