The word “steroids” is used for several very different types of drugs, which is one of the main sources of confusion around the topic. This guide covers the key facts about steroids, with a focus on anabolic-androgenic steroids (AAS): what they are, how they differ from the corticosteroids prescribed for conditions like asthma, how they affect the body, how they are regulated, and what the evidence says about their risks.
What are steroids?
In chemistry, a steroid is a compound with a characteristic structure of four connected carbon rings. Many naturally occurring hormones share this structure, including cortisol, testosterone, and estradiol, all of which are made in the body from cholesterol.
As medications, “steroids” usually refers to one of two very different drug classes: corticosteroids and anabolic-androgenic steroids. They share a basic chemical structure but act on different receptors and have very different effects.
Corticosteroids
Corticosteroids, such as prednisone and dexamethasone, are synthetic versions of hormones produced by the adrenal glands. They are widely prescribed to reduce inflammation and suppress immune activity in conditions such as asthma, rheumatoid arthritis, eczema, and allergies.
Long-term corticosteroid use can cause side effects including bone loss, muscle weakness, high blood pressure, raised blood sugar, and suppression of the body’s own adrenal hormone production. Corticosteroids do not build muscle. With prolonged use, they can contribute to muscle loss.
Anabolic-androgenic steroids
Anabolic-androgenic steroids are testosterone and synthetic substances chemically and pharmacologically related to it. They are described as “anabolic” because they promote tissue building, particularly muscle, and “androgenic” because they produce male-typical characteristics.
When people talk about steroids in bodybuilding, sports, or physique enhancement, they are referring to AAS rather than corticosteroids.
Why the distinction matters
Corticosteroids and AAS have different purposes, different effects on muscle, and different risk profiles. Information about one class does not apply to the other. For example, the safety of a short course of prescribed corticosteroids says nothing about the safety of non-medical AAS use, and vice versa.
How do anabolic steroids work?
AAS act mainly by binding to androgen receptors in muscle and other tissues. This activates genes involved in muscle protein synthesis, which can increase muscle size and strength over time.
AAS can also stimulate satellite cells, the muscle stem cells that donate new nuclei to growing muscle fibers, which supports further growth. Their effects are not limited to muscle: androgen receptors are found in many tissues, including skin, hair follicles, the prostate, and the brain.
Controlled research has shown that high doses of testosterone can increase muscle size and strength even without exercise, and that the effect is larger when combined with resistance training (Bhasin et al., 1996). Different compounds vary in how strongly they produce tissue-building effects compared with male-typical effects, a distinction explained in our article on anabolic vs androgenic effects.
What are anabolic steroids used for medically?
Testosterone is approved to treat male hypogonadism, a condition in which the body does not produce enough testosterone. Some other anabolic steroids have been used medically for conditions such as certain anemias and weight loss associated with chronic illness, although many of these uses have declined as other treatments have become available.
Medical use is not the same as non-medical use
Medical treatment typically aims to restore hormone levels to the normal physiological range under clinical monitoring. Non-medical use often involves doses well above that range, multiple compounds, and products from unregulated sources.
This distinction matters when interpreting new research. In February 2025, the US Food and Drug Administration (FDA) required class-wide labeling changes for testosterone products, removing the boxed warning about increased risk of adverse cardiovascular outcomes and adding a warning about increased blood pressure. These changes were based on the TRAVERSE trial and blood pressure monitoring studies (FDA, 2025).
TRAVERSE studied testosterone replacement in men with hypogonadism and elevated cardiovascular risk (Lincoff et al., 2023). Its findings apply to medically supervised replacement therapy. They do not establish the cardiovascular safety of supraphysiological, non-medical AAS use.
Are anabolic steroids legal?
In the United States, anabolic steroids are Schedule III controlled substances under the Controlled Substances Act. Congress placed them in this category through the Anabolic Steroid Control Acts of 1990 and 2004, and the Designer Anabolic Steroid Control Act of 2014 expanded the list to address newly developed “designer” compounds (DEA, 2025).
In August 2023, the Drug Enforcement Administration (DEA) published a final rule updating its regulations to incorporate the substances added by the 2014 Act. Substances that meet the legal definition of an anabolic steroid are controlled under Schedule III even if they are not specifically named on the list (DEA, 2025).
As Schedule III substances, AAS can be legally obtained in the US only with a valid prescription. Laws differ between countries, and in competitive sport, anabolic agents are prohibited at all times under the World Anti-Doping Agency (WADA) Prohibited List. For more detail, see our article on steroid industry regulation.
How common is anabolic steroid use?
A meta-analysis of studies from around the world estimated the global lifetime prevalence of AAS use at about 3.3%, with considerably higher rates among men than women and among recreational athletes than the general population (Sagoe et al., 2014).
Among US adolescents, the Monitoring the Future survey found that 1.4% of eighth graders and 1.2% of tenth and twelfth graders reported steroid use in 2024 (DEA, 2025).
What are the risks of non-medical steroid use?
The risks of AAS use depend on the compounds, doses, duration of use, and individual factors. The evidence comes mainly from observational studies, because long-term trials of supraphysiological use would not be ethical. Even so, several effects are well documented.
Hormonal suppression
AAS suppress the hormonal signals that drive the body’s own testosterone production. After use stops, natural production may take months or longer to recover, and in some people it remains low. Our article on testosterone recovery after steroids explains this process in detail.
Fertility
The same hormonal suppression can sharply reduce sperm production. Our article on steroids and male fertility explains how AAS affect male reproductive function.
Cardiovascular effects
AAS use is associated with unfavorable changes in blood lipids, particularly lower HDL cholesterol, as well as increased blood pressure and changes in heart structure and function. Our article on how steroids affect cholesterol levels covers the lipid evidence.
Liver effects
Some orally active AAS are associated with liver strain and, more rarely, serious liver conditions. These effects are linked mainly to a chemical modification that allows these compounds to survive passage through the liver.
Psychological effects and dependence
AAS use has been associated with mood changes, irritability, and, in some individuals, aggression, although the evidence on aggression is mixed. Low mood can also occur after use stops. Research also suggests that around 30% of AAS users may develop dependence (Pope et al., 2014).
Effects in women
In women, AAS can cause virilization, including deepening of the voice, increased body and facial hair, and enlargement of the clitoris. Some of these changes, such as voice deepening, may be permanent (Pope et al., 2014).
Unregulated products
Products sold outside the regulated pharmaceutical supply may be mislabeled, contain different substances or amounts than stated, or be contaminated. This adds uncertainty beyond the effects of the drugs themselves.
Common misconceptions about steroids
Several beliefs about steroids are not supported by evidence. A muscular appearance does not prove steroid use, steroid use does not replace training or nutrition, and the effects of one compound do not apply to every compound. Our article on common steroid misconceptions examines these and other claims in detail.
The bottom line
The most important of the key facts about steroids is that the term covers different drug classes. Corticosteroids reduce inflammation and are widely prescribed, while anabolic-androgenic steroids are testosterone-related compounds that can increase muscle size and strength.
AAS have legitimate medical uses, mainly testosterone replacement for hypogonadism, but non-medical use typically involves much higher doses and is associated with hormonal, reproductive, cardiovascular, liver, and psychological risks. In the US, AAS are Schedule III controlled substances, and in competitive sport they are prohibited at all times.
Anyone with questions about steroid use, past or present, or its effects on their health should speak with a qualified healthcare professional.
References
Bhasin S, Storer TW, Berman N, et al. The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men. New England Journal of Medicine. 1996;335(1):1–7.
Drug Enforcement Administration. Anabolic steroids: drug fact sheet. DEA Diversion Control Division. Accessed October 2026.
Lincoff AM, Bhasin S, Flevaris P, et al. Cardiovascular safety of testosterone-replacement therapy. New England Journal of Medicine. 2023;389(2):107–117.
Pope HG Jr, Wood RI, Rogol A, Nyberg F, Bowers L, Bhasin S. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocrine Reviews. 2014;35(3):341–375.
Sagoe D, Molde H, Andreassen CS, Torsheim T, Pallesen S. The global epidemiology of anabolic-androgenic steroid use: a meta-analysis and meta-regression analysis. Annals of Epidemiology. 2014;24(5):383–398.
US Food and Drug Administration. FDA issues class-wide labeling changes for testosterone products. February 28, 2025.
