Anti-doping information goes stale quickly, so the date matters. As of September 26, 2026, athletes competing under the World Anti-Doping Code are operating under the 2026 WADA Prohibited List, which took effect January 1, 2026. WADA updates the list annually, and a substance can be prohibited at all times, only in competition, or only in particular sports.
That is why performance-enhancing drugs in sport cannot be reduced to a list of steroids. The anti-doping framework also covers hormones, stimulants, diuretics and masking agents, blood manipulation and other prohibited methods. Some legitimate medications require athletes to check restrictions or obtain a Therapeutic Use Exemption.
This article explains the main categories and risks without giving instructions for misuse. For an actual medication or competition decision, the current official rules should always override an article.
What counts as a performance-enhancing drug?
In everyday conversation, the term PED is often used to mean anabolic steroids. In anti-doping, the category is much broader. Prohibited substances and methods can include hormones, stimulants, agents that change blood oxygen carrying capacity, masking agents and some medications used for common medical conditions.
The World Anti-Doping Agency publishes the Prohibited List, and national anti-doping organizations such as the U.S. Anti-Doping Agency provide athlete education. A substance can be prohibited at all times, only in competition, or only in certain sports.
1. Anabolic agents and anabolic steroids
Anabolic-androgenic steroids are synthetic substances related to testosterone. In medicine, hormone therapies can have legitimate uses. In sport, anabolic agents may be misused in an attempt to increase muscle size, strength or recovery.
Potential harms associated with steroid misuse can involve the cardiovascular system, liver, reproductive system, mood and hormone regulation. The exact effects vary by substance and individual, but “performance-enhancing” does not mean medically safe.
Anti-doping rules prohibit a broad range of anabolic agents. Athletes should not assume that a product is acceptable simply because it is marketed as a supplement or obtained without a prescription.
2. Erythropoietin, or EPO
Erythropoietin is a hormone involved in red blood cell production. Medical forms of EPO are used to treat certain types of anemia. In endurance sport, EPO has been misused in an attempt to increase the blood’s oxygen-carrying capacity.
More red blood cells can improve oxygen delivery, but artificially manipulating that system can also increase serious health risks. USADA notes that blood doping involving EPO can thicken the blood and increase the risk of blood clots, stroke, heart disease and embolism.
EPO became one of the most famous doping substances because of high-profile endurance-sport cases, but its notoriety should not obscure the core issue: it is a medically powerful substance, not a harmless shortcut.
3. Blood doping
Blood doping refers to prohibited methods used to increase red blood cell mass or oxygen transport. It can involve EPO, blood transfusions or synthetic oxygen carriers.
Transfusions have legitimate medical purposes after major blood loss. In sport, using transfusions to improve endurance creates both ethical and medical concerns. USADA identifies risks including increased cardiovascular stress, clotting and, with transfusions, transmission of infectious disease if blood handling is unsafe.
Because this is a prohibited method rather than a single “drug,” it shows why anti-doping rules extend beyond the contents of a pill or injection.
4. Human growth hormone
Human growth hormone, commonly shortened to hGH, is naturally produced by the body and also exists as a prescription medication for specific medical conditions. It has been misused in sport in an attempt to influence body composition, recovery or tissue growth.
USADA lists potential effects of hGH misuse that include joint and tissue changes, high blood pressure, heart problems, diabetes and other serious complications. Claims that hGH is a safe recovery aid should therefore be treated with caution.
5. Stimulants
Stimulants can affect alertness, attention, heart rate and perception of fatigue. The category includes prescription medicines as well as other compounds. Some stimulants are prohibited in competition at specified thresholds or conditions, while others may be permitted when used appropriately.
This is an area where medication checks matter. An athlete being treated for a legitimate condition may still have anti-doping responsibilities. The correct response is not to stop prescribed medication without medical advice. It is to check the rules and, where required, follow the Therapeutic Use Exemption process.
6. Diuretics and masking agents
Diuretics increase urine production and are used medically for conditions such as hypertension and fluid retention. In sport, they may be misused to reduce body weight quickly in weight-category sports or to make other prohibited substances harder to detect.
USADA warns that unsupervised diuretic use can lead to dehydration, electrolyte problems, cramps, dizziness, loss of coordination and dangerous changes in blood pressure.
The anti-doping concern is therefore both direct and indirect: a diuretic can affect the body and can also function as a masking agent.
7. Beta-2 agonists
Beta-2 agonists are commonly used to treat asthma and other respiratory conditions. Anti-doping rules distinguish between different substances, inhaled amounts and routes of administration.
This is a good example of why athletes with legitimate health needs should use official medication-checking tools. A medicine can be medically appropriate yet still have sport-specific restrictions.
8. Hormone and metabolic modulators
Anti-doping lists also include substances that affect hormone signaling or metabolism. Some are legitimate medicines used in cancer treatment, fertility care or other clinical settings. Their presence on a prohibited list reflects the possibility that they can alter physiological pathways relevant to performance or be used to counter side effects of other doping substances.
Because this category includes many prescription drugs, athletes should never make medication decisions based only on whether a product “sounds performance enhancing.” The official list and medical guidance are more reliable than the product’s everyday purpose.
Why athletes may take performance-enhancing substances
The reasons are not always as simple as “wanting to cheat.” Pressure can come from competition, body image, contract uncertainty, rehabilitation, weight requirements, team culture or the belief that competitors are already gaining an advantage.
Understanding those pressures does not excuse rule violations. It helps explain why effective prevention requires more than testing. Education, medical access, realistic recovery expectations and cultures that do not reward dangerous shortcuts all matter.
What is a Therapeutic Use Exemption?
A Therapeutic Use Exemption, or TUE, is a formal process that can allow an athlete to use an otherwise prohibited medication or method when there is a genuine medical need and the applicable criteria are met.
The purpose is to protect both health and fair competition. Anti-doping rules should not force an athlete to go without necessary treatment, but medical need has to be documented through the appropriate process.
Requirements vary by competition level and anti-doping organization, so athletes should check well before competing whenever possible.
Supplements can create a separate doping risk
Dietary supplements deserve special attention because regulation and labeling do not always provide the certainty athletes expect. A product may contain an undeclared ingredient, a different amount than the label suggests or a substance that is prohibited in sport.
“Natural,” “herbal” and “legal” are not anti-doping classifications. Neither is “available online.” Athletes remain responsible for what enters their bodies under strict-liability anti-doping systems.
Third-party tested supplement programs can reduce risk, but no supplement strategy can make risk zero. Athletes should involve qualified sports-medicine and nutrition professionals rather than experimenting based on testimonials.
Why anti-doping rules change
Science changes, new substances emerge and sporting bodies gather new evidence. WADA updates the Prohibited List annually, with additional technical guidance and monitoring throughout the year.
That means a blog post should never be used as a final medication-clearance tool. This article can explain categories and risks, but the current official list is what matters for competition.
Anti-doping is also a sports-management issue
Doping cases affect much more than an individual athlete. They can change results, sponsorships, team reputation, legal exposure, athlete welfare and public trust.
Sports organizations therefore need clear education, medication-checking procedures, testing policies and communication plans. Coaches and support staff also need boundaries. Encouraging, facilitating or concealing prohibited use can create serious consequences.
Common anti-doping questions
Are all steroids banned in sport?
Many anabolic agents are prohibited, but anti-doping status depends on the exact substance and rules. Athletes should check the current official Prohibited List rather than generalizing from the word “steroid.”
Is caffeine a banned performance-enhancing drug?
Caffeine has been monitored by anti-doping authorities but is not currently prohibited by WADA. Rules can change, so current official sources should always be checked.
Can an athlete take asthma medication?
Often yes, but anti-doping restrictions can depend on the specific medication, route and amount. Athletes should use an official medication-checking resource and seek a TUE when required.
What is blood doping?
Blood doping is the misuse of methods or substances to increase red blood cell mass or oxygen transport, such as EPO or prohibited transfusion methods.
Can a legal supplement cause a positive test?
Yes. Supplements can be contaminated or mislabeled. Anti-doping organizations routinely warn athletes that supplement use carries risk.
The governing source is WADA’s current Prohibited List. The 2026 list is valid from January 1, 2026 and remains the current list as of this article’s September 26, 2026 review. USADA also publishes a useful health-effects overview.
This article is educational and does not provide medical, doping or medication advice. Athletes should consult qualified medical professionals and their applicable anti-doping organization.
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