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Sports Nutrition Supplements: Do They Work?

Sportsman putting protein powder in shaker after working out

Whether you’re a serious athlete looking to gain a competitive edge or a non-athlete who would like to get more out of your fitness regimen, you may have wondered if sports nutrition supplements are worth taking. Sports nutrition supplements include powders, pills, drinks and snack bars intended to boost athletic performance in some way, usually through building muscle, increasing energy, improving endurance or assisting in weight loss.

The effectiveness of some sports supplements – namely protein, creatine and caffeine supplements – is well-known and backed by strong research. But not all sports supplements may live up to the claims on their labels. Elizabeth Traxler, RD, LD, a Registered Clinical Dietitian with the Clinical Nutrition Department at University Hospitals, weighs in on the benefits of some of the more popular sports supplements.

Protein Supplements

Usually promoted as a way to build muscle, protein supplements are made from either milk- or plant-based protein. These supplements are typically sold as powders that can be mixed with water, milk, a milk substitute or other liquids. A significant benefit of protein supplements is their convenience. For example, it’s easier and quicker to drink a protein shake after a workout than to prepare and eat a healthy high-protein meal.

“For resistance training, studies have shown that protein supplements can help increase muscle production and lessen post-workout muscle soreness and fatigue,” says Traxler. “However, most people can obtain all the protein they need from their diet. Whole foods like eggs, fish, chicken, turkey, beans, dairy products and soy are preferred protein sources. These foods also contain other nutrients, healthy fats, carbohydrates and fiber for additional health benefits.”

Milk-Based vs. Plant-Based Protein Powders

Milk-based protein powders such as whey and casein are popular due to their high concentration of certain essential amino acids that stimulate muscle growth. However, milk-based protein powders may not be appropriate for people who have milk allergies or follow plant-based diets. In those cases, a soy- or pea-based proteins powders would be preferred.

Whey protein has a high content of leucine, the essential amino acid needed for muscle repair, and is digested quickly to help with muscle repair after activity. Soy protein is digested at a similarly fast rate and also has a complete amino acid profile.

Traxler says, “The main difference between whey and soy protein is that soy protein has a lower leucine content. However, most existing research comparing the effects of taking either whey or soy protein has not shown any significant differences in performance benefits for muscle gain or increased strength, particularly in individuals engaged in recreational exercise and fitness rather than competitive sports.”

Can You Have Too Much Protein Powder?

Excess protein in your diet can reduce the diversity of good fiber-fermenting bacteria in your gut while increasing the presence of protein-fermenting bacteria. The latter promote inflammation and make people more susceptible to type 2 diabetes, obesity and other diseases. For this reason, Traxler says protein supplementation should be personalized to one’s specific needs based on age, sex, weight, height, activity level, dietary intake and other factors.

Are Protein Powders Regulated?

Like other types of dietary supplements, protein powders are not regulated for safety and quality by the Food and Drug Administration. Studies have shown that many protein powders on the market contain elevated levels of heavy metals, bisphenol-A (BPA), pesticides and other contaminants linked to cancer and other health conditions.

In particular, studies have reported higher levels of contaminants in weight gainer protein supplements. Weight gainers, also called mass gainers, are high-calorie dietary supplements that contain protein, carbohydrates and fat and are intended to promote healthy weight gain. Studies have not found significant levels of contaminants in standard whey protein supplements, which are safe if consumed in moderation or as directed.

However, Traxler cautions consumers to research any protein supplement they take to find out if it has been tested and reviewed by a third-party agency such as the National Science Foundation (NSF), which provides information on the safety, purity and quality of the ingredients in such products. Brands that are not third-party tested and those with concerning test results should be avoided.


Creatine monohydrate, more commonly known as creatine, is an organic substance involved in the production of energy for muscle contractions. Although creatine can be obtained from food sources such as meat or fish, some individuals may have difficulty getting the right amount of creatine from foods alone to optimize their athletic performance.

A popular sports supplement, man-made creatine is available as a powder or pill and in energy bars and drink mixes. Studies indicate that creatine supplements can increase lean muscle mass, strength and exercise performance. According to the International Society of Sports Nutrition (ISSN), creatine is safe to use at recommended doses and does not cause long-term detrimental effects.


Another substance that has strong and consistent research showing positive effects on exercise performance is caffeine. Consuming caffeine prior to physical activity may help delay the depletion of carbohydrates used during exercise, improving endurance. Other potential benefits of caffeine include improved strength, reduced fatigue and better mood during exercise.

Traxler says, “The benefits of using caffeine to boost athletic performance may not be noticeable if a person regularly drinks caffeinated beverages. Consuming more than 400 mg of caffeine per day is unsafe and will not produce any additional benefits.”

Other Sports Nutrition Supplements

The many sports nutrition supplements available today also include multivitamins, branched-chain amino acids (leucine), omega-3 fatty acids, glucosamine, glutamine, beta-alanine, beetroot and green tea extract, each of which is purported to offer different performance benefits. However, research supporting the effectiveness of most of these supplements is still limited at this time.

Do Athletes Need to Take Sports Nutrition Supplements?

Traxler advises that most athletes and non-athletes should examine their diets and eating habits before they begin taking dietary supplements.

“In general, it’s better to get your protein, carbohydrates, healthy fats, vitamins and minerals from food sources. Also, people can often boost their athletic performance by changing the timing of their meals to align better with the timing of their athletic activity or exercise.”

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The Clinical Nutrition Department at University Hospitals provides comprehensive nutrition services to improve the health and quality of life for patients. Learn more.