Anabolic steroids

AAS — testosterone and derivatives · Androgens

Research reference only. Pepdex does not sell, supply or track this compound, and nothing here is guidance to use it — this page exists so the evidence and the risks are visible.

What it is

Synthetic derivatives of testosterone that activate androgen receptors in muscle, bone, and many other tissues. Medically used for diagnosed hypogonadism, certain anemias, and muscle-wasting disease. Non-medical use targets muscle growth and performance.

How it works

Anabolic-androgenic steroids are synthetic relatives of testosterone, and they build muscle through two routes at once. They bind the androgen receptor in muscle, which raises protein synthesis and reduces breakdown, and they also blunt the catabolic signalling that normally limits how much muscle a body will hold. The "anabolic-androgenic" name reflects an attempt to separate muscle-building from masculinising effects; no compound achieves that separation cleanly, which is why every one of them carries androgenic consequences alongside the muscle. The body reads high external androgen as a signal to shut down its own production, and that shutdown is the root of most of what follows.

What human evidence shows

The muscle effect is well documented — controlled trials (Bhasin 1996, NEJM) measured lean-mass gain at supraphysiologic doses, and the response is dose-dependent. That is not the open question. The open question, and the reason this entry exists, is what those doses cost: the harm literature below is larger and better replicated than the performance literature.

The studies, one by one

That supraphysiologic TESTOSTERONE builds muscle is not in dispute: the landmark randomised trial put 43 men into four groups for ten weeks and found substantial gains, around 6 kg of fat-free mass in the testosterone-plus-training arm. That result is about testosterone specifically and does not establish equal efficacy for every synthetic steroid in this class.
The harm evidence comes largely from cohort and imaging studies of long-term users rather than randomised trials, because randomising people to years of supraphysiologic doses would not pass an ethics committee.
The landmark cardiac imaging study compared 86 long-term users against 54 non-using weightlifters and found impaired ventricular function and greater coronary plaque associated with use, with duration the strongest correlate. It is cross-sectional, so it establishes a strong association rather than proving causation.
Cohort studies report higher mortality among identified users than matched controls. The populations are identified users rather than exclusively former users, and residual confounding by other drug use and lifestyle cannot be eliminated.
Recovery of natural testosterone production after long-term use is often prolonged, and a proportion of long-term users do not fully recover.
Beyond the endocrine and cardiac picture, documented hazards include kidney injury, blood clots, heart attack, stroke and sudden death, tendon rupture, injection-site infection, and blood-borne infection from shared equipment.

Half-life and how long it lasts

Half-lives vary enormously by ester and route, from hours for some orals to weeks for long-acting injectables, and it is prohibited in tested sport. Oral 17-alpha-alkylated compounds are chemically modified to survive first-pass liver metabolism, and that same modification is what makes them hepatotoxic. Aromatisable compounds convert to oestrogen, which drives water retention and gynaecomastia; non-aromatising compounds avoid that but tend to be harder on lipids.

Risks

Extensive and well-documented: suppression of natural testosterone production (can persist long after stopping), infertility, cardiovascular harm (adverse lipid changes, left-ventricular hypertrophy, elevated cardiac event risk in long-term users), liver stress with oral 17-alpha-alkylated compounds, gynecomastia, acne, hair loss, and psychiatric effects. Post-use hypogonadism frequently requires medical management. Counterfeit and contaminated products dominate the unregulated market.

Who should never touch it

Children and adolescents, where androgens can close growth plates prematurely and cause precocious puberty
Anyone with existing cardiovascular disease, high haematocrit, or a clotting history
Anyone with liver disease, especially considering oral compounds
Anyone who wants children in the foreseeable future
Anyone with a history of mood disorder, psychosis or aggression problems
Anyone with a family history of hormone-sensitive cancer
Women considering compounds that cause irreversible virilisation — voice deepening and clitoral enlargement do not reverse

Interactions worth knowing

Anticoagulants — steroids can potentiate warfarin, and the erythrocytosis pushes clot risk the other way. A genuinely dangerous combination to manage casually.
Insulin and diabetes medication, since androgens alter insulin sensitivity in both directions depending on compound.
Anything hepatotoxic — alcohol, paracetamol, oral SARMs — stacked with an oral 17-alpha-alkylated steroid.
Isotretinoin, which shares lipid and liver burden.
Tell any clinician treating your blood pressure that you are using it — do not adjust prescribed medicines around it yourself.

Stacking interactions

Documented interactions with other things people research. A compound not listed here does not mean the combination is safe — only that no specific interaction is on file.

CautionWinstrol