Sports Supplements

Product Oversight and Marketing

Dietary Supplement Health and Education Act of 1994 (DSHEA)

Food and Drug Administration (FDA)

  • Regulates dietary supplements under separate regulations from those that cover “conventional” foods and drug products (prescription and over the counter).

  • Considers “dietary ingredients” a vitamin, mineral, herb, or botanical; amino acid; substance to increase total dietary intake; or a concentrate, metabolite, constituent, or various combinations or derivatives of the aforementioned categories.

  • Under the DSHEA, a dietary supplement manufacturer is responsible for ensuring that the product is safe before it is marketed.

  • Is responsible for taking action against any unsafe product after it reaches the market. They are not authorized to review supplements for safety and effectiveness before hitting the market.

  • Unlike other drugs, manufacturers need not register or get approval from the FDA before producing or selling dietary supplements.

  • It is the manufacturer’s responsibility to make sure that product label information is truthful and not misleading; manufacturer also dictates product purity.

  • Established a Dietary Supplements guideline in 2007 to require Current Good Manufacturing Practices (CGMP) for dietary supplements. Established guidelines require that dietary supplements be produced in a quality manner, not contain contaminants or impurities, and have accurate labeling.

  • Postmarketing responsibilities of the FDA include monitoring safety (voluntary dietary supplement adverse event reporting) and inspecting product information (claims, labeling, package inserts, and accompanying literature). These guidelines do not address the underlying safety of the supplement itself and remain nonbinding to the manufacturer.

  • The Federal Food, Drug, and Cosmetic Act (1997), with updated draft guidance published in 2016, requires manufactures to notify the FDA of marketing supplements with New Dietary Ingredients (NDIs). The NDI term applies to dietary ingredients not marketed in the United States before October 15, 1994. The company must provide information at least 75 days before hitting the market with supplemental information demonstrating why they feel this new ingredient will be reasonably safe. Between 1995 and 2014, the FDA has evaluated over 750 NDI notifications.

Federal Trade Commission (FTC)

  • Responsible for overseeing truth in dietary supplement advertising.

  • Requires that claims on products be symptom specific, not disease oriented. For example, statements such as “supplement X can stimulate the immune system” are acceptable. Even then, these supplements must additionally include: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent disease.”

  • Despite FTC requirement that claims on products be symptom specific, not disease oriented, one study that analyzed websites to assess the nature of marketing claims for the eight best-selling herbal products found that this rule is not always followed. The study revealed that most available information derives from vendor sites and half of these sites claim that these products can treat, prevent, diagnose, or cure specific diseases. Physicians should be aware that these claims were on the first page of the most commonly used Internet search engines.

Center for Food Safety and Applied Nutrition Adverse Event Reporting System (CAERS)

  • The Center for Food Safety and Applied Nutrition (CFSAN) maintains an adverse event (AE) monitoring system known as CAERS (CFSAN Adverse Events Reporting System).

  • Primary reporting system established by the FDA is a voluntary reporting system; less than 1% of all AEs are reported through CAERS per a report by the Office of the Inspector General.

  • Dietary supplements are not evaluated for safety, and manufacturers are not required to prove safety. Is FDA’s responsibility to prove harmful consequences.

  • In 2006, the Dietary Supplement and Nonprescription Act mandated reporting of serious AEs by supplement manufacturers (deaths or life-threatening events, initial hospitalizations or prolongations of stay, disabilities or permanent impairments, congenital anomalies or birth defects), requiring supplement labels to include the manufacturer’s contact information.

  • Between January 2018 and March 2020, the FDA received over 14,000 reported AEs related to a wide variety of supplements. Though there was broad heterogeneity in the types of AEs reported, clinicians and consumers alike should closely scrutinize dietary supplements prior to consumption. Particularly at-risk populations include those who are pregnant or breastfeeding, and in children, unless specifically noted.

  • Consumers and providers are encouraged to additionally report adverse reactions on the FDA Safety Reporting Portal ( ).

Other Oversight

  • The US Pharmacopoeia (USP) has set standards for natural product potency ranges. Their goal is “to improve global health through public standards and related programs that help ensure the quality, safety, and benefit of medicines and foods.”

  • Currently only 18 brands of dietary supplements are verified by the USP.

  • ConsumerLab ( ) is a helpful site that tests the supplements of various companies and reports their potencies.


  • In a 2018 survey, at least 70% of the population in every age group stated they used dietary supplements, with usage increasing with age.

  • Dietary supplements are estimated to be a US$349 billion industry worldwide by 2026 (US$62 billion in the United States).

  • Supplements are marketed to athletes’ fears. Many athletes believe that they have to use supplements to stay equal to competitors or to gain a “competitive edge.” They frequently fear that competitors are using supplements. More than 50% of Olympic-caliber athletes stated that they would take a banned substance if it meant they would win every competition for the next 5 years, even if they would then die from adverse effects of the substance. Among elite athletes, performance differences are minuscule between first-place and fourth-place winners; even minor enhancements may mean the difference between victory and defeat.

  • Marketing companies rely heavily on testimonials of personal experiences, especially from famous people and athletes. Many companies successfully sell unproven products. Supplement manufacturers often sponsor supplement studies, and negative findings may not be published. Word of mouth and hopes to gain a “competitive edge” help fuel sales.

  • Sports supplements frequently have no “instant” effects, so companies often add stimulants to give an “energy boost.” Despite a new FDA label law to ensure accuracy in labeling of dietary supplements, there continues to be inaccurate labeling. In one FDA analysis of ephedra supplements, between 6 and 20 other ingredients were found. Cases have been reported of legal supplements containing trace amounts of illegal supplements. Is truly a “buyer beware” market ( Box 6.1 ).

    BOX 6.1

    • Most ergogenic aids lack scientific proof.

    • Most supplements have not been tested adequately for efficacy, purity, or safety.

    • Be careful of misleading product information.

    • “Natural” does not mean safe.

    • “More” is seldom better.

    • Nothing replaces a well-balanced diet that includes a variety of high-quality foods.

    • Athletes use supplements at their own risk.

Commonly Used Athletic Performance Supplements

  • Optimal dose and long-term side effects of most supplements are not known.

  • Manufacturers recommend doses and durations that have been tested, and claimed side effects apply to these instructions.

  • Many athletes may use higher doses than recommended and/or use them for longer periods, which raises concern for unknown effects.

  • Most supplements try to enhance the normal effects of exercise on the body.


  • Claims:

    • Acutely improve exercise capacity; chronic effect results from stimulation of muscle protein synthesis and anabolism of muscle protein.

    • Soy, sesame, and peanut proteins are an excellent source of arginine.

  • Mechanism:

    • May promote secretion of endogenous growth hormone (GH). Precursor in the synthesis of creatine.

    • Augments the production of nitric oxide.

    • Increased vasodilation can speed up removal of metabolic waste products, such as ammonia and lactate.

  • Efficacy:

    • Little scientific evidence available to support claims of promoting and increasing functional capacity in healthy, athletic participants.

    • A 2016 systematic review did not support using arginine, either on its own or with creatine or caffeine, for enhanced recovery or athletic performance.

    • Particularly in well-trained athletes, no effect on nitric oxide concentration, blood flow, or exercise metabolites.

    • Significantly increases muscle blood volume but does not affect strength performance.

    • Effects on muscle protein synthesis are likely a net effect in combination with nitric oxide, as well as concurrent elevation of other amino acids.

  • Side effects:

    • May result in gastrointestinal (GI) distress (bloating, anorexia, diarrhea) or cardiovascular effects (lowering of blood pressure).

    • Flushing reported occasionally with intravenous (IV) administration.

  • Dosage: 2–20 g daily is used in studies.

Bovine Colostrum (BC)

  • Claims:

    • BC supplementation may increase insulin-like growth factor-1 (IGF-1) levels.

    • May positively influence exercise performance characterized by short bursts of activity.

    • Improvement in body composition (e.g., gaining fat-free mass) shown in nonelite athletes, not found in elite athletes.

    • Claims include increased immune function after exercise.

  • Mechanism:

    • Stimulates growth factors, including structurally identical IGF-1, which has an anabolic effect and is involved in the regulatory feedback of GH.

    • GH stimulates hepatic production of IGF-1, which provides negative feedback to reduce pituitary production of GH.

  • Efficacy:

    • Limited studies show consistent beneficial effects on recovery and exercise performance and improved immune function in special athletic populations.

    • Mixed results on improvements in lean body-mass gains and no evidence of changes in either GH or testosterone levels were noted in a 2014 systematic review.

  • Side effects:

    • Occasional minor GI complaints, including flatulence and nausea.

    • High percentage of participants complained about the “unattractive” taste of the beverage.

  • Dosage: 20–60 g daily.

Branched-Chain Amino Acids (BCAAs)

  • Claims:

    • Important source of energy in prolonged endurance exercise.

    • Proposed to increase endurance in long tennis matches, soccer, marathons, long-distance swimming, and cycling activities.

    • May contribute to increased body fat loss and maintenance of a high level of exercise performance.

    • Claims to decrease chronic fatigue/overtraining symptoms.

  • Mechanism:

    • Replenishes loss of BCAAs (leucine, isoleucine, and valine) used as fuel, increases protein synthesis and GH secretion, shifts leucine metabolism to fat metabolism, stimulates fat metabolism over glycogen in hypocaloric diets, and prevents decrease in plasma glutamine.

    • Inhibits dietary tryptophan transport across blood-brain barrier, leading to decreased brain serotonin (associated with several brain regions that control central fatigue).

  • Efficacy:

    • Most studies show neither beneficial nor detrimental effect of BCAAs.

    • A 2019 meta-analysis indicated that there was a large decrease in delayed onset of muscle soreness when utilizing BCAAs compared with placebo.

    • Studies of effect of BCAAs in hypocaloric states are limited.

    • Have not been shown to reduce chronic fatigue/overtraining symptoms, and preworkout/event BCAA loading has no effect on performance.

  • Side effects: Fatigue and ergolytic effects have been reported.

  • Dosage:

    • Usually combined with other amino acids.

    • Range: 5–20 g daily or before exercise. May be safe to take a total of 40 grams daily.


  • Claims:

    • Most widely used stimulant in the world and is present in beverages such as coffee, teas, colas, some energy drinks, foods containing chocolate, energy bars, and over-the-counter medications sold to increase alertness.

    • Central nervous system (CNS) stimulant that increases alertness and can make intense exercise feel easier.

    • Preworkout formulas usually contain caffeine.

    • Mildly elevates fat-burning and metabolic rate.

    • Some claims state that mild caffeine consumption may decrease risk for diabetes.

  • Mechanism:

    • Lipid-soluble compound metabolized by the liver and through enzymatic action results in three metabolites: paraxanthine, theophylline, and theobromine.

    • Due to its lipid solubility, crosses the blood-brain barrier.

    • Acts on the CNS as an adenosine antagonist but may also have an effect peripherally on substrate metabolism and neuromuscular function.

  • Efficacy:

    • Potential improvement in endurance exercise, high-intensity team sports, and strength-power performance.

    • Studied in special force operations where military personnel routinely undergo training and real-life operations in sleep-deprived conditions. Vigilance maintained or enhanced with caffeine in addition to run times and completion of an obstacle course.

    • May also be ergogenic by enhancing lipolysis and decreasing reliance on glycogen utilization.

    • Most likely to help with endurance events but not with shorter events like sprinting or weightlifting.

    • The American College of Sports Medicine (ACSM) in 2018 specifically recommended against consuming energy drinks before, during, or after strenuous exercise due to the lack of safety and efficacy data.

  • Side effects:

    • Lethal dose in adult humans is estimated to be 10 g.

    • Higher doses of caffeine may induce mild tremor, tachycardia, insomnia, GI upset, chest pain, arrhythmias, and nervousness at doses over 600 mg/day.

  • Dosage:

    • Single doses of ∼200 mg improve cognitive function and 2–6 mg/kg body weight doses 15–60 minutes before exercise.

    • The National Collegiate Athletic Association (NCAA) limits athletes to 15 mcg/mL appearing in their urine, which is equal to consuming 6–8 cups of coffee 2–3 hours before competition. The International Olympic Committee (IOC) limits athletes to 12 mcg/mL.

Carbohydrate Supplements

  • Claims:

    • Used to restore muscle glycogen after exercise, maintain plasma glucose during endurance events (especially those lasting more than 90 minutes), and maximize muscle glycogen before significant glycogen-depleting exercise (e.g., marathon, long-course triathlon).

    • Various sugars are used, including sucrose, glucose, fructose, and maltodextrin (popular among ultraendurance athletes).

  • Mechanism:

    • Increased blood glucose stimulates insulin production and GLUT-4 translocation in muscle, which results in increased glucose uptake and glycogen storage in muscle.

    • Carbohydrates with high glycemic index increase plasma glucose quickly and serve as a fuel source in sustained exercise.

  • Efficacy:

    • Reviews are mixed for pre-exercise supplementation and carbohydrate loading.

    • Benefits of supplementation after exercise and during long events (more than 90 minutes) are well supported.

  • Side effects: Individual GI tolerance varies with different types of carbohydrate supplements, and some athletes may experience dyspepsia and GI upset.

  • Dosage:

    • The ACSM released their latest position statement in 2016 regarding nutrition and athletic performance, which includes guidance for daily needs and acute fueling strategies.

    • Low-intensity athletes should aim for 3–5 g/kg daily, and those with very high-intensity demands lasting 4–5 hours per day should take in 8–12 g/kg daily.

    • Before exercise: 1–4 g/kg 1–4 hours pre-exercise; carbohydrate loading for events of greater than 90 minutes of sustained activity requires 10 g/kg/day of carbohydrates for 1.5–2 days before the event. For multiple sessions with fewer than 8 hours to recover, can consume 1–1.2 g/kg/h for 4 hours, then resume daily needs.

    • During exercise: 30–60 g/h for events lasting 1–2.5 hours. Exercise lasting longer than 2.5 hours may require up to 90 g/h. Sources include sports drinks (5–10 oz/15 min), sports gels or candies (2 gels with water), or gummy candy (a handful per hour with water).

    • Though not addressed in the ACSM position statement, recommendations after exercise: 0.7–1 g/kg every 2 hours for the first 4 hours after exercise (first 90 minutes postexercise is most important). Best if started within 30 minutes of stopping exercise. Use a food source with a high glycemic index. Addition of protein to carbohydrate supplement increases glycogen production.


  • Claims:

    • Trace mineral used for weight loss and for enhancement of glycemic control in the treatment of diabetes.

    • Proposed for the treatment of hyperlipidemia and hypercholesterolemia.

    • Used by athletes in attempts to gain muscle and lose fat.

  • Mechanism:

    • Functions in carbohydrate, protein, and fat metabolism as a cofactor that enhances action of insulin and uptake of amino acids into muscles.

    • Food sources include broccoli, grape juice, and English muffins.

    • Improves lipid profile and is theorized to sensitize insulin receptors in the brain, resulting in appetite suppression and downregulation of insulin secretion.

    • Glycogen synthesis increases in chromium-deficient individuals.

    • Exercise may result in loss of chromium, but athletes conserve chromium and probably do not become deficient.

  • Efficacy:

    • Possibly effective when used to reduce cholesterol, but probably ineffective for weight loss.

    • Mild hypoglycemic effect caused by a mechanism similar to metformin.

    • Considerable scientific evidence indicates that chromium has no effect on body composition when taken in supplement form.

  • Side effects:

    • Chromium interferes with iron metabolism and zinc absorption.

    • Though there are theoretical adverse effects with long-term use, the Institute of Medicine determined there is no upper intake limit for chromium. This does not mean that no toxic effects might be associated with high intake.

    • Commercial preparations containing ephedrine are restricted; low doses of the combined preparation have been found to cause hypertension, stroke, and death.

  • Dosage:

    • Chromium picolinate is more easily absorbed than other forms of chromium; chromium is complexed to picolinate to facilitate absorption.

    • Dietary recommendation is 35 mcg/day for adult males and 25 mcg/day for adult females, with supplements generally containing 200–600 mcg.

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