5 Things to Know Before You Take Any Supplement

From checking the label to talking to your physician or pharmacist, here’s expert advice on the steps to take before you seek out supplements

Donna Shryer,

AARP

Comments

En español

Published June 12, 2026

A person's hand holds a white vitamin bottle, pointing a finger at the "Supplement Facts" nutritional label to check the daily value percentages and ingredients.

Alamy Stock Photo

The supplement aisle has never been more crowded — or more confusing. Gone are the days when Flintstones chewables and adult once-daily vitamins were the only choices. Today, as many as 100,000 different supplement products are on the market, and nearly 3 out of 4 adults 60 and older take them.

But unlike prescription and over-the-counter medications, supplements don’t require federal approval for safety or effectiveness before they reach store shelves. And like any drug, they can cause side effects and interact with other medications.

With that in mind, here are a few simple steps to help you decide whether you should take a supplement and how to choose wisely.

1. You may not need it

Before buying a supplement, the most important step is to determine whether your body needs it.

Dr. Pieter Cohen, an internist and leader of the Cambridge Health Alliance Supplement Research Program, puts it plainly: “Unless you have a health condition that requires a supplement, you don't need to take one.” Yet most of his patients never ask whether they need one.

“The great majority of my patients don’t ask me,” he says. “Like everyone else, they go to the store, see something they want, they start taking it.”

And it’s a common misconception that aging alone means you need more supplements, says Alice Lichtenstein, a professor of nutrition science and policy at Tufts University’s Friedman School of Nutrition. “Nutrient requirements don’t necessarily change as we get older,” she says. Some do, she notes — certain older adults lose stomach acid and genuinely need B-12 supplementation. But it’s not true for everyone.

A healthy decision is based on an objective measure, most often a simple blood test, Lichtenstein adds. “That’s what your health care provider can tell you,” she says.

About 75 percent of American adults take a dietary supplement daily, but less than half tell their doctors, says Emily Rose Britton, senior manager at USP, an independent nonprofit that sets quality standards for supplements. “Don't be shy. Don’t be afraid of judgment. It’s encouraged to share your supplement usage with your health care providers.”

2. Supplements don’t stand in for food

If your diet isn’t great and you think a supplement can pick up the slack — not so fast.

“One should not view vitamin supplements as a substitute for maintaining a healthy dietary pattern,” says Lichtenstein. She notes that whole foods contain compounds, particularly in plants, that science doesn’t yet fully understand. These compounds work together in ways a single-ingredient pill can’t duplicate.

“It’s assumed if you consume food, you’re getting the compounds,” she says. “If you consume a nutrient supplement, you’re not,” she says.

Chad Worz, a board-certified geriatric pharmacist, agrees that no supplement can make up for a consistently poor diet. “It’s not a catchall,” he says.

Lichtenstein puts it memorably: “I don’t think we should think of dietary supplements as a ‘get out of jail free’ card and not worry about what we eat.”

3. More is not better

Knowing you need a supplement is only part of the equation. How much you take matters just as much.

“If you get 100 percent of all the vitamin A you need, I can assure you 200 percent is not going to be better for you, and over a very long period of time, it could be bad for you,” says Lichtenstein. She cautions that supplements can push levels into risky territory, especially when a balanced diet already covers much of the need.

Worz explains why some vitamins are riskier than others. “Vitamin A, D, E and K are fat-soluble vitamins, and they accumulate [in the body],” he says. "That’s part of the reason that those particular vitamins can cause high levels or potential problems — because they hang around in your body a lot longer.”

Water-soluble vitamins like C are more forgiving. “Your urine might turn orange because you’re taking so much vitamin C,” Worz says. “That’s the body’s way of telling you, ‘I’ve got enough.’ ”

Vitamin D is one example where more is not necessarily better. About 37 percent of U.S. adults 60 and older take it, often for bone health, but large trials found no clear fracture-prevention benefit, and some higher-dose regimens were linked to more falls or lower bone density.

A practical check: Look at the daily value on your supplement label. If it says 100 percent of a given vitamin, that’s the full recommended amount in a single day. If it says 200 percent or 300 percent, that’s a red flag — not a bonus.

Lichtenstein says to start with your health care provider. They can tell you whether you’re within the normal range and whether the next step is a supplement or a few changes to your diet.

4. What’s on the label isn’t always what’s in the bottle

There’s no required testing of a supplement’s quality, purity or consistency before it reaches store shelves.

Cohen’s research confirms the consequences. “Study after study, including many of ours, have demonstrated that what’s on the label is not what’s actually in the products,” he says.

The workaround: Look for the USP Verified Mark or NSF certification on the label. Specific to USP, Britton says the stamp means “what’s on the label is what’s in the bottle” and that USP has reviewed the entire manufacturing process. But with as many as 100,000 different supplement products on the market, fewer than 1 percent carry the USP Verified Mark.

Cohen recommends visiting USP’s website (usp.org) or NSF’s website (nsf.org) to find certified brands of the specific ingredient you need. He also advises sticking with single-ingredient supplements rather than proprietary blends.

If evidence is limited or unavailable for one ingredient, it’s nonexistent for a custom mixture. Cohen’s advice is simple: “Just buy supplements that list the ingredient you’re looking for on the bottle.”

And be skeptical of what’s printed on the package. Cohen warns that manufacturers can claim a supplement is good for your liver, boosts the immune system or helps with memory, “but they don’t have to have any evidence from human clinical trials to support what they’re saying.”

Britton agrees: “If a product’s claim sounds too good to be true, it probably isn’t true.”

5. Your doctor or pharmacist should weigh in

“Just because you can buy it over the counter doesn’t mean it’s inherently safe,” Worz says, “particularly if you are on other medications, and as you get older.”

One reason: kidney function gradually declines as you age, which means your body clears both supplements and medications more slowly — and that raises the risk when the two collide.

Cohen explains that supplements can change how much medication actually reaches your bloodstream, either amplifying a drug’s effect or blocking its absorption.

“Maybe the sneakiest one is vitamin E,” says Worz. “People think, It’s vitamin E; it’s good for me. But at higher doses, it can have a significant anticoagulant effect.” For someone on blood thinners like Eliquis, Xarelto or warfarin, that could dangerously thin the blood.

St. John’s wort does the opposite. Often taken for mood and depression, it speeds up the metabolism of blood thinners and reduces their effectiveness.

One supplement makes a blood thinner too strong. Another makes it too weak. That’s not something you can guess on your own.

“All this is a good reminder to bring your supplements in to your doc and ask, ‘Is this safe for me to take?’ ” Cohen says. Your pharmacist can also field questions about supplement-drug interactions.

It comes down to this: Tell your doctor and pharmacist about every supplement you take. Bring every bottle, every gummy, every powder to your next doctor’s appointment or pharmacy visit. “I have not met a pharmacist who doesn't want to talk to people about questions they have, especially with respect to medications,” says Worz. “They’ll find time if you have questions.”

%{postComment}%

Donna Shryer is a contributing writer who covers health and wellness. She is the author of two books on nutrition, and her work has appeared in McKnight's Long-Term Care News and publications for leading health systems.