If you exercise regularly, and especially if you are an athlete and compete in sporting events, you should know that a well-balanced diet and plenty of fluids are important for maximizing your physical performance. However, you may be wondering if dietary supplements could help you train better, improve your performance, or gain a competitive advantage.

These products are sometimes referred to as “ergogenic aids or supplements,” but in this fact sheet we will refer to them simply as “performance-enhancing supplements. Merchants of these supplements may claim that their products improve strength or endurance, help you reach your performance goal faster, or increase your tolerance for more intense training. They may also claim that their supplements may help prepare your body to improve exercise, reduce your risk of injury during training, or help with recovery after exercise.

Performance-enhancing supplements cannot replace a healthy diet, but some of them may have some value, depending on the type and intensity of your activity. Other supplements don’t seem to work, and a few may be harmful to health.

If you are thinking about taking a supplement to improve your physical performance, consult a health professional. If you have a trainer with knowledge of sports medicine, ask about performance-enhancing supplements. It is important to talk to an expert if you are a teenager or have a medical condition. It’s also important to know if the medications you take might interact with the performance-enhancing supplements you’re considering.

What are the ingredients in supplements to improve exercise and physical performance?

Performance-enhancing supplements can have many ingredients, such as vitamins and minerals, proteins, amino acids, and herbs, in different amounts and in many combinations. These products are on the market in several ways, including capsules, tablets, liquids and powders.

This fact sheet below describes the ingredients found in performance-enhancing supplements in alphabetical order. You’ll learn about the efficacy and safety of consuming each of the ingredients and find expert advice on their use. Please note, however, that many performance-enhancing supplements on the market contain more than one ingredient, and ingredients may act differently when combined. Because combinations of most ingredients have not been studied, we do not know how safe and effective they are when it comes to improving performance.

You may be surprised to learn that, in general, manufacturers of these supplements don’t do studies on people to find out if their products really work and are safe. When studies (mainly by researchers at universities) are done on the ingredients and combinations of ingredients in supplements to improve physical performance, they usually involve a small number of people who are taking the supplements for only a few days, weeks, or months. Much of this research is done on healthy young men, but not women, middle-aged adults, older adults, or teenagers. And often, studies have not investigated the use of the ingredients or their combinations in people who engage in the same physical activities as you. For example, the results of a study with weightlifters do not apply to you if you are a distance runner.