Performance enhancement drugs: evidence-based review (for educational purposes only)

Disclaimer: This article is for general educational purposes and does not provide medical advice. Performance-enhancing drugs (PEDs) can carry significant health risks and legal consequences. Always consult a qualified healthcare professional before making decisions about your health.

Quick summary

• “Performance enhancement drugs” (PEDs) refer to substances used to improve physical strength, endurance, muscle mass, focus, or recovery.
• Some PEDs (e.g., anabolic-androgenic steroids, erythropoietin) can increase performance but are linked to serious short- and long-term health risks.
• Many products marketed as “boosters” or “legal steroids” lack strong scientific evidence and may contain undeclared ingredients.
• Use without medical supervision increases the risk of heart disease, hormonal disorders, psychiatric effects, and liver damage.
• Safer, evidence-based alternatives often include structured training, nutrition optimization, sleep, and addressing underlying medical conditions.

What is known

1. Anabolic-androgenic steroids (AAS) increase muscle mass and strength

Anabolic-androgenic steroids are synthetic derivatives of testosterone. Clinical and experimental studies show that they can significantly increase muscle size and strength, especially when combined with resistance training.

However, evidence from long-term observational studies links non-medical AAS use to:

• Increased risk of heart attack and stroke
• High blood pressure and abnormal cholesterol levels
• Liver toxicity (especially with oral forms)
• Hormonal suppression (leading to infertility and testicular shrinkage in men)
• Mood disorders, aggression, and dependence

Major medical organizations, including the Endocrine Society and the American Heart Association, warn against non-prescribed use due to these risks.

2. Erythropoietin (EPO) and blood manipulation improve oxygen delivery

Erythropoietin is a hormone that stimulates red blood cell production. In medicine, it is prescribed for specific types of anemia. When misused in sports, it increases oxygen-carrying capacity, potentially improving endurance performance.

Evidence shows that artificially raising red blood cell levels increases the risk of:

• Blood clots (deep vein thrombosis, pulmonary embolism)
• Stroke and heart attack
• Dangerously thickened blood (polycythemia)

Because of these risks, its use without medical indication is considered unsafe and is banned in competitive sports.

3. Stimulants may enhance alertness and short-term performance

Stimulants such as amphetamines and certain prescription ADHD medications can improve attention, reaction time, and perceived energy. Caffeine—legal and widely used—also has evidence supporting modest improvements in endurance and focus.

However, stronger stimulants carry risks:

• Elevated heart rate and blood pressure
• Arrhythmias
• Anxiety, insomnia, and dependence
• Risk of overdose

Use without medical supervision increases the likelihood of misuse and adverse outcomes.

4. Growth hormone (GH) has limited performance benefits in healthy adults

Human growth hormone is approved for certain medical conditions. In healthy adults, evidence suggests it may change body composition slightly (e.g., reduce fat mass), but consistent improvements in strength or athletic performance are not well established.

Documented risks include joint pain, swelling, insulin resistance, and possible increased cancer risk with prolonged misuse.

5. Many over-the-counter “performance enhancers” are poorly regulated

Dietary supplements marketed for muscle growth or endurance often contain multiple ingredients. Independent testing has found that some products contain undeclared anabolic steroids or stimulants.

Regulatory agencies such as the U.S. Food and Drug Administration (FDA) warn that supplements are not reviewed for effectiveness before marketing. Quality and safety can vary widely.

What is unclear / where evidence is limited

• Long-term outcomes: Many studies focus on short- to medium-term effects. The full lifetime cardiovascular and psychiatric impact of non-medical PED use is still being studied.
• Low-dose or intermittent use: Some users claim that “cycling” or lower doses reduce harm. High-quality clinical data confirming safety with these patterns are lacking.
• Stacking (combining drugs): Many users combine multiple substances. There is limited controlled research on the interaction effects, making risk prediction difficult.
• New compounds: Selective androgen receptor modulators (SARMs) and novel peptides are marketed online, but human safety data are limited. Regulatory agencies have issued warnings about potential liver toxicity and cardiovascular risk.

Overview of approaches

“Performance enhancement drugs” is a broad category rather than a single medication. Approaches vary depending on the goal (muscle gain, endurance, cognitive focus, recovery).

• Hormonal agents: Anabolic steroids, testosterone derivatives, growth hormone. These alter endocrine systems and carry systemic risks.
• Blood-boosting strategies: EPO, blood transfusions (illegal in sport). Increase oxygen delivery but raise clotting risk.
• Stimulants: Prescription ADHD medications, illicit stimulants, high-dose caffeine products.
• Supplements: Creatine (supported by evidence for strength and high-intensity performance), beta-alanine (modest endurance benefits), protein supplementation (useful when dietary intake is insufficient).

Unlike prescription drugs for diagnosed conditions, most non-medical performance enhancement lacks a favorable risk–benefit balance. Evidence-based sports nutrition and training strategies are generally safer and supported by stronger data.

For broader health context, see our overview of cardiovascular risk factors and how lifestyle influences long-term outcomes. You may also find our guide to hormonal health basics helpful in understanding endocrine effects.

Legal and ethical considerations

Most competitive sports organizations, including the World Anti-Doping Agency (WADA), ban many PEDs. Non-medical possession or distribution of certain substances may also be illegal depending on local laws.

Evidence summary table

Statement	Confidence level	Why
Anabolic steroids increase muscle mass and strength.	High	Supported by randomized trials and observational data.
Non-medical AAS use increases cardiovascular risk.	High	Consistent associations in cohort studies and mechanistic evidence.
EPO improves endurance but increases clot risk.	High	Clear physiological mechanism and documented adverse events.
Growth hormone substantially improves athletic performance in healthy adults.	Low to medium	Limited and inconsistent performance data.
“Cycling” or stacking reduces health risks.	Low	No high-quality controlled studies confirm safety.
Some supplements contain undeclared active drugs.	High	Documented by regulatory agency testing and recalls.

Practical recommendations

Safer general measures for performance

• Follow a structured, periodized training plan.
• Ensure adequate protein and total calorie intake based on activity level.
• Prioritize sleep (7–9 hours for most adults).
• Address iron deficiency, thyroid disorders, or low testosterone only after medical evaluation.
• Consider evidence-supported supplements (e.g., creatine monohydrate) after discussing with a healthcare professional.

When to see a doctor

• Chest pain, shortness of breath, or fainting during or after exercise
• Unexplained mood changes, aggression, or depression
• Sexual dysfunction or infertility
• Abnormal lab results (liver enzymes, cholesterol, hematocrit)

How to prepare for a consultation

• List all substances and supplements taken (including doses and duration).
• Note changes in mood, sleep, libido, or physical performance.
• Bring prior lab results if available.

If you are concerned about substance safety, our article on medication safety principles provides general guidance. For readers exploring general wellness topics, visit our Uncategorized health resources section for broader educational materials.

Sources

• Endocrine Society Clinical Practice Guidelines (testosterone therapy, hormone use).
• American Heart Association scientific statements on cardiovascular risk.
• World Anti-Doping Agency (WADA) Prohibited List and health consequences documents.
• U.S. Food and Drug Administration (FDA) warnings on bodybuilding and sexual enhancement supplements.
• National Institute on Drug Abuse (NIDA): Anabolic Steroids and Other Appearance and Performance Enhancing Drugs (APEDs).
• International Olympic Committee consensus statements on dietary supplements and athlete health.