Using Dietary Supplements Wisely

What are dietary supplements?

Dietary supplements include vitamins, minerals, herbal products, and protein supplements meant to provide additional nutrition to the diet. These products are available in a wide variety of formulations including liquids, powders, drinks, energy bars, tablets, and capsules. You do not need a prescription to buy dietary supplements. They are sold over-the-counter in grocery stores and pharmacies across the United States.

Why do people take dietary supplements?

People take supplements for several reasons. Some people take supplements when they think they are not eating properly. These people may benefit from a multivitamin or nutritional supplement if they are not able to get enough nutrients in their diet alone.

Some supplements may help to decrease the risk of developing certain diseases or improve symptoms caused by certain medications or medical conditions. For example, many women take calcium supplements to reduce the risk of developing osteoporosis, especially if they have a low body weight, are post-menopausal, or have been taking steroid medications such as prednisone.

It is important to remember that dietary supplements are not meant to prevent, treat, or cure diseases. They can be beneficial to your health when taken with your pharmacist or health provider's guidance.

Are supplements regulated?

The Food and Drug Administration (FDA) regulates dietary supplements, but under a different set of rules than those that cover food and medications. The FDA monitors ingredients, checks labeling, and ensures that there are no false claims made about efficacy of a particular supplement.

Some supplement manufacturers volunteer for increased scrutiny for good manufacturing practices. If a company meets these stricter regulations, then a special symbol and the letters GMP (Good Manufacturing Practices) will appear on the supplement's label indicating the ingredients contained in the supplement are in the amount stated on the label and the supplement does not contain harmful containments. A supplement verified by the U.S. Pharmacopeial Convention will have the USP Verified mark on the label. However, these stricter manufacturing practices not imply that these supplements will work better or should be substituted for medical advice.

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Can supplements be harmful?

Supplements may cause health problems and could worsen some health conditions or have unintended consequences. For example, some supplements can cause skin sensitivity and adverse reactions in people undergoing radiation treatment for cancer. There is also evidence that taking too much or even normal doses of a supplement may cause problems such as stomach upset, diarrhea, constipation, or rash.

Supplements can also interact with your prescription medications. This can be dangerous because many people forget to tell their doctor or pharmacist about any over-the-counter products they take. For example, St. John's Wort (one of the most common herbal supplements) has been reported to have 247 major interactions with other medications. Gingko biloba, garlic, fish oil, and ibuprofen can put patients taking blood thinners at a higher risk of bleeding. Taking too much protein supplementation can decrease kidney function, especially if you don't drink enough water or fluids. Taking certain supplements may also alter your lab test results.

Steps to considering a dietary supplement

If you are having symptoms or notices changes in your health, you should first see your doctor or pharmacist before taking a dietary supplement for your condition. You may need medical treatment or medication, rather than a dietary supplement.

Your pharmacist is a valuable resource because they know which medications can interact with supplements, and they can help you understand the benefits and possible harm of taking a supplement. Tell your pharmacist about your allergies; the current medications you are taking, including prescription and over-the-counter products; and any health conditions such as high blood pressure or diabetes.

In conclusion, supplements can be beneficial for some patients. Although they are easily purchased over-the-counter, there are some risks associated with their use. Always talk to your pharmacist or healthcare provider before taking a supplement.

See also:

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AHFS® Patient Medication Information is used with permission. ©2025, the American Society of Health-System Pharmacists, Inc. (ASHP). The ASHP Data is a part of the AHFS Drug Information®️; ASHP is not responsible for the accuracy of transpositions from the original context.