Types of performance-enhancing substances

Athletes use performance-enhancing substances to augment training adaptations and improve sport performance. Ideally, these substances also support health and adhere to the ethical and regulatory guidelines of their sport. However, concerns regarding unfair competitive advantages and potential adverse effects have led most athletic governing bodies to maintain lists of banned substances. Athletes caught using these substances risk suspension, forfeiture of medals, or lifetime bans in repeated violations.

While many substances are prohibited, various nutritional supplements and ergogenic aids are permissible and commonly used to maximize performance. Athletes must be informed about the legality and safety of any substance before use.

Distinction between drugs and dietary supplements

The key distinction between a drug and a dietary supplement is FDA approval for safety and effectiveness. Drugs require extensive testing before they can be marketed, while dietary supplements can be sold with minimal regulation unless a health risk is identified.

Dietary supplements may provide macronutrients, micronutrients, or bioactive compounds (such as protein, creatine, or caffeine) that can influence health or performance. Nutritional strategies, such as carbohydrate loading before competition, are considered part of an athlete’s diet, whereas a carbohydrate product in tablet or powder form is classified as a dietary supplement.

Definition of products that can be sold as dietary supplements

Dietary supplements in the U.S. must meet the following criteria:

1. The product (excluding tobacco) must supplement the diet and contain one or more of the following:
   • A vitamin
   • A mineral
   • An herb or botanical
   • An amino acid
   • A dietary substance intended to increase total dietary intake
   • A concentrate, metabolite, constituent, extract, or combination of the above ingredients
2. The product must be intended for ingestion and cannot be marketed as a conventional food or a sole item within a meal.

The FDA regulates dietary supplements under the Dietary Supplement Health and Education Act (DSHEA) of 1994, which prohibits the marketing of adulterated or misbranded supplements. Manufacturers are responsible for ensuring compliance with DSHEA and FDA labeling regulations.

Supplement labels cannot claim to diagnose, treat, or cure diseases. Structure–function claims are permitted but must include an FDA disclaimer.

Banned substances and doping regulations

​​The World Anti-Doping Agency (WADA) oversees international doping regulations and maintains a standardized list of prohibited substances. In the United States, the United States Anti-Doping Agency (USADA) governs doping control for the U.S. Olympic and Paralympic movement. Professional sports leagues may establish their own anti-doping policies, which can differ from WADA and USADA standards.

Other organizations, including Major League Baseball (MLB), the National Collegiate Athletic Association (NCAA), and the National Football League (NFL), maintain separate lists of banned substances and associated penalties. Athletes, coaches, and strength and conditioning professionals must stay informed about these regulations.

Commonly prohibited substances in athletic competition

The following categories of substances are subject to anti-doping regulations. Exact rules may vary depending on the governing body (e.g., WADA, NCAA, or professional leagues).

• Stimulants: Amphetamine, ephedrine, and methamphetamine are banned. Caffeine is not prohibited by WADA but is monitored, while the NCAA bans caffeine at high urine concentrations (≥15 µg/mL). Anabolic agents: Testosterone, nandrolone, stanozolol, and other anabolic steroids.
• Alcohol and beta-blockers: Prohibited in sports requiring fine motor control, such as archery and shooting, typically during in-competition testing only. Diuretics and masking agents: Substances that can alter drug test results or manipulate body weight.
• Substances of abuse and cannabinoids: Includes heroin, cocaine, and synthetic cannabinoids. Cannabis (THC) is prohibited in-competition. Peptide hormones and analogs: Growth hormone (hGH), erythropoietin (EPO), and related compounds. Anti-estrogens: Tamoxifen, formestane, and other agents used to counteract estrogenic effects.
• Beta-2 agonists: Medications such as salbutamol and formoterol. Some inhaled forms are permitted at defined therapeutic doses or with a therapeutic use exemption (TUE).