Performance enhancement drugs — evidence-based review (for educational purposes only, not medical advice)

This article reviews what is known — and what remains uncertain — about performance enhancement drugs (PEDs). It is intended for general education. It does not promote or recommend the use of any substance. Decisions about medications or supplements should be made with a qualified healthcare professional.

Quick summary

• “Performance enhancement drugs” include a wide range of substances: anabolic steroids, stimulants, hormones, and some prescription medicines used off-label.
• Some substances can increase muscle mass, strength, endurance, or alertness — but often with significant health risks.
• For many commonly used PEDs, short-term effects are better studied than long-term safety.
• Non-medical use is illegal in many countries and banned in most organized sports.
• Lifestyle factors (training, sleep, nutrition) have stronger safety profiles and are foundational for performance.

What is known

1. Anabolic-androgenic steroids (AAS)

Anabolic steroids are synthetic derivatives of testosterone. In clinical medicine, testosterone is prescribed for clearly defined conditions (for example, diagnosed hypogonadism) under strict supervision.

Evidence shows:

• AAS can increase muscle mass and strength beyond training alone.
• They can suppress the body’s natural testosterone production.
• They are associated with increased risks of cardiovascular disease (heart attack, stroke), high blood pressure, abnormal cholesterol, and blood clots.
• Psychiatric effects (mood swings, aggression, depression) and dependence can occur.
• In men: infertility, testicular shrinkage, gynecomastia (breast tissue growth). In women: voice deepening, menstrual disruption, irreversible virilization.

Major medical bodies (e.g., Endocrine Society, American Heart Association) warn against non-medical steroid use because of these risks.

2. Stimulants (e.g., amphetamines, ephedrine, high-dose caffeine)

Stimulants increase alertness and reduce fatigue. Some are prescription medications for ADHD or narcolepsy. Others are found in supplements.

Evidence shows:

• Short-term improvements in reaction time and perceived energy are possible.
• Risks include arrhythmias, high blood pressure, anxiety, sleep disruption, overheating, and in rare cases sudden cardiac events.
• Dependence and withdrawal symptoms can occur with some stimulants.

High caffeine intake is common in sport; moderate doses may improve endurance performance in some individuals, but effects vary widely.

3. Erythropoiesis-stimulating agents (e.g., EPO)

Erythropoietin (EPO) stimulates red blood cell production and is used medically for certain types of anemia.

Evidence shows:

• Increasing red blood cells can improve oxygen delivery and endurance performance.
• Thickened blood increases the risk of clots, stroke, heart attack, and sudden death.

Non-medical use is considered particularly dangerous and is banned in competitive sports.

4. Human growth hormone (hGH)

hGH is approved for specific medical conditions (e.g., growth hormone deficiency).

Evidence shows:

• It may change body composition (reduced fat mass, modest increase in lean mass).
• Clear performance benefits in healthy adults are not well established.
• Risks include joint pain, swelling, insulin resistance, and possibly increased cancer risk with long-term misuse.

5. Selective androgen receptor modulators (SARMs)

SARMs are experimental compounds designed to target muscle and bone tissue. None are approved for performance enhancement.

• Some studies show increases in lean mass.
• Long-term safety data are lacking.
• Product contamination and inaccurate labeling are common in the supplement market.

6. “Natural” supplements marketed for performance

Creatine monohydrate is one of the most studied legal supplements. Evidence supports its benefit for high-intensity, short-duration exercise in many people, with a generally favorable safety profile when used as directed.

However, many other supplements marketed as “testosterone boosters” or “fat burners” have limited or poor-quality evidence. Some have been found to contain undeclared prescription drugs or steroid-like substances.

What is unclear / where evidence is limited

• Long-term outcomes: Many studies focus on weeks or months. The impact of years of non-medical PED use is less well studied but concerning case reports and observational data suggest serious harm.
• Real-world dosing patterns: Research often uses controlled doses; actual use may involve stacking (combining multiple drugs) at higher doses, increasing risk.
• Women and adolescents: Much of the research is based on adult men. Data in women and younger individuals are more limited, and risks may differ.
• New compounds: Designer steroids and SARMs frequently enter the market before proper safety evaluation.

Overview of approaches

“Performance enhancement drugs” is a broad category rather than a single medication. Approaches range from:

• Prescription hormones used for diagnosed medical conditions (e.g., testosterone replacement under endocrine supervision).
• Illicit anabolic steroid cycles used for bodybuilding or strength sports.
• Stimulant misuse for alertness or weight loss.
• Legal supplements such as creatine, beta-alanine, and caffeine.

For approved medications (e.g., testosterone, EPO), dosing and indications are defined in official prescribing information from regulatory authorities such as the U.S. Food and Drug Administration (FDA) or the European Medicines Agency (EMA). Non-medical use outside these indications carries additional risk.

If your interest is related to body composition or metabolic health, you may find our overview on hormonal balance and metabolic function helpful. For cardiovascular safety considerations, see heart health and exercise risk assessment.

Table: Key statements and confidence level

Statement	Confidence level	Why
Anabolic steroids increase muscle mass and strength	High	Supported by randomized trials and clinical observations
Non-medical steroid use increases cardiovascular risk	High	Consistent findings from observational studies and mechanistic data
hGH significantly improves athletic performance in healthy adults	Low–Medium	Mixed evidence; modest body composition changes but unclear functional gains
SARMs are safer than anabolic steroids	Low	Insufficient long-term safety data; reports of liver toxicity and suppression
Creatine is effective for high-intensity performance	High	Multiple meta-analyses support benefit with good safety profile

Practical recommendations

Safer general measures for performance

• Structured, progressive training with adequate recovery.
• Sleep 7–9 hours per night for hormonal and cognitive performance.
• Evidence-based nutrition: sufficient protein intake, balanced carbohydrates, adequate hydration.
• Periodized training and rest to avoid overtraining.

Our guides on sports nutrition basics and safe muscle building strategies provide practical, lower-risk alternatives.

When to see a doctor

• Chest pain, shortness of breath, or palpitations.
• Severe mood changes, depression, or aggression.
• Unexplained fatigue, sexual dysfunction, infertility concerns.
• Abnormal lab results (e.g., liver enzymes, cholesterol).

How to prepare for a consultation

• List all substances used (prescription, over-the-counter, supplements).
• Note duration, frequency, and any side effects experienced.
• Bring recent laboratory results if available.
• Be honest — clinicians are focused on safety, not punishment.

Sources

• Endocrine Society Clinical Practice Guidelines (Testosterone Therapy in Men with Hypogonadism).
• American Heart Association scientific statements on anabolic steroid and cardiovascular risk.
• World Anti-Doping Agency (WADA) Prohibited List and medical information.
• U.S. Food and Drug Administration (FDA) drug safety communications on SARMs and anabolic steroids.
• European Medicines Agency (EMA) product information for erythropoiesis-stimulating agents and growth hormone.
• International Society of Sports Nutrition (ISSN) position stand on creatine supplementation.

Note: The safest and most sustainable performance improvements usually come from training, recovery, and nutrition — not from high-risk pharmacological shortcuts.