What Are Supplements? Health Benefits, Risks, More
Diet & NutritionNutrients & Supplements

Supplements: Potential Benefits, Known Risks, and More

Supplements: Potential Benefits, Known Risks, and More
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Updated on October 20, 2025
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Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.

More than half of American adults take dietary supplements, according to a survey of more than 3,000 people.

 They’re nonfood products with vitamins, minerals, herbs, botanicals, amino acids, enzymes, or other ingredients intended to enhance the diet.

 Supplements come in an array of over-the-counter forms, including tablets, gummies, powders, tinctures, and more, which manufacturers claim have a wide variety of health benefits.

While certain supplements hold some evidence-backed results, others market promises unfounded by science. What’s more, some supplements may be harmful to your health if taken at improper doses or if mixed with certain prescription medicines or other drugs, and they may not contain the ingredients listed on the label. Here’s a closer look at the potential health benefits, identified risks, and everything else you should know about dietary supplements.

Potential Health Benefits of 5 Commonly Used Supplements

There are tens of thousands of studies on the potential health benefits of dietary supplements. Below are some of the more commonly used supplements and what current research has to say about them.

1. Vitamin D

Vitamin D is naturally produced in the body when exposed to sunlight, and it promotes calcium absorption to build and support strong bones. There are two forms: vitamin D2, which is found in plant-based foods, and vitamin D3, which is produced in the skin when it’s exposed to sunlight. Foods like milk can be fortified with vitamin D, but adequate levels may be difficult to get from diet alone.

 There also may be times when our bodies don’t produce sufficient amounts of vitamin D — particularly in the darker winter months — so supplementation may help.
Some research suggests that vitamin D and calcium supplementation together may help prevent osteoporosis, a disease that weakens bones as we age, making them more susceptible to fractures or breaks. One meta-analysis concluded that both dietary and supplemental forms of calcium and vitamin D increased bone mineral density in postmenopausal women, possibly lowering the risk of hip fractures.

But research is mixed. Other research found that vitamin D supplements were not useful in reducing the risk of bone fractures in middle-aged and older adults who were not specifically vitamin D deficient.

2. Vitamin C

Vitamin C is one of the building blocks of healthy blood vessels, cartilage, and muscles, and it’s long been associated with maintaining a healthy immune system.

 Many people consume sufficient amounts of vitamin C in their diet, and it’s found in citrus fruits and certain vegetables.

Research suggests that vitamin C may play an important role in preventing chronic disease. Some studies have found, for example, that vitamin C supports cardiovascular health, though more consistent research is needed to determine its effect on preventing heart disease.

 Vitamin C supplements are popular for relief from cold symptoms, but research hasn’t fully proven those effects.

3. Magnesium

Magnesium helps regulate the body’s calcium and blood sugar levels, and it also helps the body make protein. It’s found in a number of foods, including nuts, seeds, and beans, but you can also add it to your diet through supplementation.

Some research has found that magnesium supplementation may help manage type 2 diabetes, and other studies have found that magnesium may have protective benefits for the heart in patients with diabetes.

Magnesium supplementation may also help reduce symptoms of depression, according to some research.

 But not all studies on the connection between mood and magnesium have shown consistent results, so more thorough research is needed to pinpoint magnesium’s potential effects on mental health concerns.

4. B Vitamins

Vitamin B, which is made up of a group of eight vitamins, plays a vital role in allowing the body to use energy. The eight B vitamins are: B1 (also called thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxal phosphate), B7 (biotin), B9 (folic acid or folate), and B12 (cobalamin).

B vitamins have been linked with a number of possible health benefits in studies, including a reduced risk of heart disease in people with normal kidney function. But researchers note that age, gender, and genetics continue to be important factors in cardiovascular disease risk.

 Other research found that B2 supplementation may reduce the duration and frequency of migraine attacks, while different studies suggest that it may play a role in preventing cognitive decline.

5. Probiotics

Some research suggests that gut-friendly probiotics in supplement form may have positive health impacts, particularly when it comes to digestion. Probiotics may be especially helpful in preventing and treating diarrhea related to antibiotic use.

 Other studies suggest that probiotics may relieve symptoms of irritable bowel syndrome (IBS), but the latest guidance from the American Gastroenterological Association states that there isn’t enough evidence to make a recommendation on probiotics for IBS.

6. Zinc

Zinc has been linked with a number of potential health benefits, perhaps most notably a boosted immune system. One review from Singapore, for example, found that zinc supplementation via capsules or lozenges with 5 milligrams (mg) to 43 mg of zinc can potentially reduce cold duration by slightly more than two days.

Zinc supplements may also slow the progression of macular degeneration, an age-related eye disease that causes vision loss.

7. Creatine

Creatine is an amino acid (the building blocks of proteins) and helps provide energy for muscles, particularly while exercising.

 Creatine is a popular supplement among bodybuilders and athletes. Many people take it after a workout to help with muscle growth, and there’s some research to support that practice.
A scoping review, in which authors looked at 16 randomized controlled clinical trials, concluded that creatine supplementation may have efficiently supported muscle growth in healthy, younger people, but additional, larger trials are recommended.

Other research suggests that creatine may be beneficial for older adults. A research review published in Canada determined that the use of creatine supplements, either with or without resistance training, can increase muscle mass and prevent falls in older adults.

To start your supplement journey, you may want to stock up on the most common one: vitamin D. We worked with experts to round up the best Vitamin D supplements here.

Weight Loss Effect of Supplements

According to a Gallup poll, 55 percent of American adults expressed a desire to slim down.

 Many of these would-be dieters turn to dietary supplements for a weight loss assist. But while numerous supplements claim to aid with weight loss, no magic one exists to melt extra pounds away.
Common ingredients in weight loss supplements include:

Research for various weight loss supplements ranges from small to large clinical trials, and those are of varying quality and sample size. Further, the findings show everything from no effect on body weight to a possible modest effect on body weight.

“There is no substantial scientific evidence that supplements for weight loss work,” explains Jodie Pepin, PharmD, clinical pharmacist at Harbor Health in Round Rock, Texas, and a clinical assistant professor of pharmacy at the University of Texas in Austin. “There really is no substitute for a healthy diet and regular exercise.”

Proceed with caution and speak to your doctor if you want to create a sustainable weight loss plan that’s tailored for your specific needs.

Potential Risks and Side Effects of Common Supplements

While supplements offer potential health benefits, it's important to consider their downsides: risks, side effects, and possible interactions with medications and chronic conditions.

Risks

Supplements may interact with prescription medications or other supplements, so tell your doctor and pharmacist about any other drugs you're taking before you try one.

Supplements are also not regulated by the FDA before they hit the market, so there’s a risk of mislabeling and contamination. Some research has shown that 14 to 50 percent of dietary supplements taken by athletes contain prohibited substances.

 Purchasing supplements that are verified by a third party is the best way to avoid buying inert or dangerous products.

Supplements can also be expensive, and they might not support your individual dietary and health needs. Always consult your physician to see if you should be taking a supplement before you do.

Side Effects

Every supplement comes with its own set of short-term and long-term risks and potential side effects, which should be discussed with your physician prior to taking them. These are some of the side effects that can occur from supplements, particularly if taken at too high of a dose:

Looking to bulk up your supplement supply? We've got recs — like our picks for the 8 best zinc supplements, recommended by RDs.

Forms of Supplements

Dietary supplements come in a number of forms. You can find them in the following formats, although this list isn’t exhaustive:

  • Tablets
  • Capsules
  • Gummies
  • Powders
  • Gel caps
  • Softgels
  • Liquids
  • Bars

How to Select and Store Supplements

Best practices for selecting and storing dietary supplements depend on the types and forms you take. Here are a few general tips to keep in mind.

Selection

When choosing a dietary supplement, check the label for a mark from one of the independent organizations that test these products for quality and safety. Look for those that say USP, NSF, or ConsumerLabs Approved. This means the product has undergone third-party testing for quality and purity.

If you have any questions about which brands to choose, ask your doctor or pharmacist. They may be able to advise you, such as whether it’s better to choose an isolated supplement or multiple supplements in combination.

Storage

To make sure you're storing your supplements appropriately, always check the product packaging for specific instructions from the manufacturer. As with all medicines, store them in a place where children can’t reach them, in a place that’s not too hot or cold.

“It is best for any product to avoid extremes of temperature such as freezing or high heat conditions,” says Lara Zakaria, PharmD, a registered pharmacist and a certified nutrition specialist based in New York City. She advises against storing supplements in your bathroom medicine cabinet. “Temperature fluctuations and humidity can damage the integrity of capsules, causing them to lose efficacy,” she says.

Avoid taking supplements past the expiration date, as they may lose their potency and expose you to potential risks not yet studied or regulated.

Dosage of Supplements

One of the biggest risks of supplements is improper dosing.

“Prior to starting a supplement, consult your physician on the dosing,” says Kathy Nguyen, MD, a primary care sports medicine physician with Memorial Hermann Medical Group in Sugar Land, Texas. “Just like any medication prescription or over-the-counter item, all supplements have a side effect profile, and too much may be harmful.” Follow your doctor’s instructions for dosage and consumption, and pay close attention to the directions on the label.

If a magnesium supplement sounds like it may make sense for you, but you're not sure which one to buy, we can help. Our list of the best magnesium supplements, recommended by experts, is a great place to start.

The Takeaway

  • According to survey data, more than half of American adults regularly take dietary supplements, which are nonfood products with vitamins, minerals, herbs, botanicals, amino acids, enzymes, or other ingredients purported to have health benefits.
  • They may be beneficial for people who are unable to meet their nutritional needs through diet alone. Supplements are also sometimes used as an integrative approach for a wide variety of health concerns, although more research is typically needed to establish the dosage and effectiveness.
  • Supplements can come with risks, including interactions with prescription medications or other supplements, and potentially dangerous side effects if the dosage is too high.
  • Always talk to your doctor, dietitian, or pharmacist before starting any new supplement, check the label for third-party testing to ensure quality and purity, and closely follow the directions on the label for safe use and storage.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Three-Quarters of Americans Take Dietary Supplements; Most Users Agree They Are Essential to Maintaining Health, CRN Consumer Survey Finds. Council for Responsible Nutrition. October 5, 2023.
  2. FDA 101: Dietary Supplements. U.S. Food and Drug Administration. June 2, 2022.
  3. Vitamin D. National Institutes of Health Office of Dietary Supplements. June 27, 2025.
  4. Liu C et al. Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials. Food & Function. December 2020.
  5. Migliorini F et al. Vitamin D and calcium supplementation in women undergoing pharmacological management for postmenopausal osteoporosis: a level I of evidence systematic review. European Journal of Medical Research. March 14, 2025.
  6. Myths and Truths about Vitamin C. Harvard Health Publishing. January 22, 2025.
  7. Vitamin C. Mayo Clinic. August 10, 2023.
  8. Morelli M et al. Vitamin C and Cardiovascular Disease: An Update. Antioxidants. December 2020.
  9. Vitamin C and Colds. MedlinePlus. February 8, 2024.
  10. Soriano-Perez L et al. Magnesium and type 2 diabetes mellitus: Clinical and molecular mechanisms. Health Sciences Review. September 2022.
  11. Cheng Y et al. Nonprescription Magnesium Supplement Use and Risk of Heart Failure in Patients With Diabetes: A Target Trial Emulation. Journal of the American Heart Association. March 26, 2025.
  12. Maobedi M et al. Magnesium supplementation beneficially affects depression in adults with depressive disorder: a systematic review and meta-analysis of randomized clinical trials. Frontiers in Psychiatry. December 21, 2023.
  13. Miao Y et al. The effect of B-vitamins on the prevention and treatment of cardiovascular diseases: a systematic review and meta-analysis. Nutrition Reviews. October 2024.
  14. Chen Y et al. Effect of Vitamin B2 supplementation on migraine prophylaxis: a systematic review and meta-analysis. Nutritional Neuroscience. September 2022.
  15. Jatoi S et al. Low Vitamin B12 Levels: An Underestimated Cause Of Minimal Cognitive Impairment And Dementia. Cureus. February 2020.
  16. Goodman C et al. Probiotics for the prevention of antibiotic-associated diarrhoea: a systematic review and meta-analysis. BMJ Open. August 2021.
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  19. Wang MX et al. Zinc Supplementation Reduces Common Cold Duration Among Healthy Adults: A Systematic Review of Randomized Controlled Trials With Micronutrients Supplementation. American Journal of Tropical Medicine and Hygiene. April 27, 2020.
  20. Blasiak J et al. Zinc and Autophagy in Age-Related Macular Degeneration. International Journal of Molecular Sciences. July 15, 2020.
  21. Creatine. Cleveland Clinic. April 26, 2023.
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  23. Candow DG et al. Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation. Journal of Clinical Medicine. April 11, 2019.
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