History

Oxymetholone was developed by Syntex in the early 1960s and remains FDA-approved with a labeled indication for the treatment of anemias caused by deficient red cell production — specifically acquired and congenital aplastic anemia, myelofibrosis, and the hypoplastic anemias due to administration of myelotoxic drugs. Historically it was also studied for other wasting and catabolic states, but many of those uses have been superseded by safer agents such as recombinant erythropoietin for anemia. It remains a niche but legitimately marketed prescription drug in the United States under the brand name Anadrol-50.

Oxymetholone, sold under the brand name Anadrol-50 (and historically Anapolon), is a synthetic anabolic-androgenic steroid (AAS). It is an orally active derivative of dihydrotestosterone, and it is a steroid — not a peptide and not a SARM. It has a real FDA-approved medical use in certain anemias and a genuine controlled-trial record in wasting illness, but it is also one of the more potent and hepatotoxic oral steroids, with serious documented effects on the liver, blood lipids, and the hormonal axis.

What it is

Oxymetholone is 2-hydroxymethylene-17α-methyl-dihydrotestosterone — a derivative of dihydrotestosterone (DHT). The methyl group at the C17 position (17α-alkylation) lets it resist hepatic first-pass metabolism, making it orally bioavailable; Anadrol is an oral tablet, not an injectable ester. That same 17α-alkylation is the structural feature responsible for the hepatotoxicity characteristic of oral AAS.

Mechanistically, like other AAS it acts as an agonist of the intracellular androgen receptor (AR), driving anabolic effects (protein synthesis, nitrogen retention, lean/muscle mass) alongside androgenic effects. As a DHT derivative it is not a substrate for aromatase, yet oxymetholone is notable for producing estrogenic-type side effects (such as gynecomastia and fluid retention) despite not aromatizing — a clinically observed but incompletely explained property thought to involve intrinsic estrogen-receptor or progestogen-like activity. Its hematologic benefit is attributed to stimulation of erythropoiesis; the FDA label states it enhances the production and urinary excretion of erythropoietin in patients with anemia due to bone marrow failure.

The claims

The FDA-approved label use is the treatment of anemias caused by deficient red cell production — acquired aplastic anemia, congenital aplastic anemia, myelofibrosis, and the hypoplastic anemias due to administration of myelotoxic drugs. Beyond the label, it has been investigationally studied for HIV-associated wasting and for insulin sensitivity and muscle wasting in maintenance hemodialysis patients.

In bodybuilding and athletic use (non-medical and illicit), oxymetholone is promoted to rapidly increase body weight, lean and muscle mass, and strength, and as a “kickstart” agent. Those uses are off-label, illegal without a prescription, and constitute doping in sport.

What the evidence actually shows

The strongest human evidence comes from clinical wasting and catabolic populations, not from healthy athletes.

For HIV-associated wasting, Hengge et al. (2003) ran a double-blind, randomized, placebo-controlled phase III trial in eugonadal men and women (n=89, 16 weeks). Oxymetholone produced statistically significant weight gain (3.0 ± 0.5 kg and 3.5 ± 0.7 kg in the two active arms versus 1.0 ± 0.7 kg with placebo) and increased body cell mass, with improved appetite and well-being (PMID 12646793, AIDS 2003;17(5):699–710; a distinct full-length report of the same trial appears in HIV Clinical Trials 2003;4(3):150–163, PMID 12815555). The dominant adverse signal was liver-associated toxicity: transaminase or GGT elevations greater than 5× baseline occurred in 43% of one active group and 25% of the other, versus 8% of placebo. An earlier open pilot study (Hengge et al. 1996, n=30 treated vs matched controls, 30 weeks) reported that oxymetholone was safe and promoted weight gain in advanced HIV-1 infection (PMID 8785183, Br J Nutr 1996;75(1):129–138).

For maintenance hemodialysis patients, Aramwit, Kobpipat, Satirapoj, Kopple, and Supasyndh (2009) conducted an RCT (n=44, 24 weeks) in which oxymetholone improved insulin sensitivity (lower HOMA index), increased fat-free/lean mass, and reduced fat mass versus placebo — again with elevated liver enzymes among treated patients (PMID 19356374, Clin Nephrol).

For healthy-athlete hypertrophy and strength, the data are limited and lower quality. The robust controlled efficacy evidence comes from clinical wasting and catabolic populations rather than rigorous trials in healthy athletes; the consistent finding is gains in body weight and lean/body-cell mass, accompanied by hepatic and lipid adverse effects. A narrative review (Pavlatos, Fultz, Monberg, Vootkur 2001, Clin Ther 23(6):789–801, PMID 11440282) summarizes the FDA-approved anemia use and other investigational applications in the context of its hepatic risks.

So the evidence that oxymetholone reliably increases weight and lean mass in humans is strong — but it is strongest in sick, catabolic populations, and it comes bundled with a consistent liver-toxicity signal.

Legal and regulatory status

In the United States, anabolic steroids are Schedule III controlled substances under the Controlled Substances Act, placed there by the Anabolic Steroids Control Act of 1990 (Pub. L. 101-647; effective Feb 27, 1991) and expanded by the Anabolic Steroid Control Act of 2004 (Pub. L. 108-358), which broadened the statutory definition at 21 U.S.C. 802(41). Oxymetholone is one of the enumerated anabolic steroids and is Schedule III. Non-prescription possession, distribution, or non-medical use is illegal. (For contrast, clenbuterol is not FDA-approved for human use and is not a scheduled controlled substance, and human growth hormone is governed separately under 21 U.S.C. 333(e) rather than via CSA scheduling.)

In sport, oxymetholone is on the WADA Prohibited List under S1 (Anabolic Agents), subcategory S1.1 (Anabolic Androgenic Steroids), and is prohibited at all times (in and out of competition), in force on the 2026 Prohibited List effective January 1, 2026. By contrast, clenbuterol and SARMs sit under S1.2 (“Other Anabolic Agents”), and HGH and hCG fall under S2 (peptide hormones and related substances) — oxymetholone is an actual steroid under S1.1.

Safety

The medical pedigree does not make oxymetholone a gentle drug; it carries the full and serious risk profile of a potent 17α-alkylated oral androgen.

Hepatotoxicity (major, characteristic of 17α-alkylated orals): dose- and duration-dependent transaminase elevations; cholestatic jaundice; peliosis hepatis (liver and splenic tissue replaced by blood-filled cysts, which can be life-threatening); and liver cell tumors (most often benign and androgen-dependent, but fatal malignant tumors have been reported). The FDA label carries explicit warnings about peliosis hepatis and liver cell tumors with prolonged use, and advises periodic liver function testing and discontinuation on hepatic dysfunction.
Cardiovascular and lipids: marked adverse lipid changes — decreased HDL (“good”) cholesterol and sometimes increased LDL — a recognized class effect of oral 17α-alkylated AAS that is associated with increased atherosclerotic risk per the FDA label. Fluid and sodium retention can worsen edema, hypertension, and heart failure.
HPTA suppression and fertility: suppression of the hypothalamic-pituitary-testicular axis with reduced endogenous testosterone, testicular atrophy, impaired spermatogenesis, and infertility; suppression may persist after discontinuation.
Estrogenic effects: despite being a non-aromatizing DHT derivative, oxymetholone is notable for causing gynecomastia and fluid retention.
Virilization (especially in women and children): hirsutism, deepening of the voice (which may be irreversible), clitoral enlargement, and menstrual irregularities; in children, premature epiphyseal closure and accelerated bone maturation.
Hematologic: the intended erythropoietic effect can overshoot into polycythemia or elevated hematocrit, raising thrombotic risk.
Other: acne, oily skin, male-pattern hair loss, mood and aggression changes, and potential prostate effects in older men. It is contraindicated in pregnancy (teratogenic and virilizing), in prostate or male breast carcinoma, and in significant hepatic dysfunction.

Bottom line

Oxymetholone is a real, FDA-approved anabolic-androgenic steroid with a genuine, controlled-trial evidence base for increasing weight and lean mass — but that evidence sits in wasting and catabolic illness (HIV wasting, hemodialysis), not in healthy recreational users, and it travels with a consistent and serious liver-toxicity signal. It is a Schedule III prescription steroid, banned at all times in sport (WADA S1.1), and one of the more hepatotoxic oral steroids, with documented risks to the liver, blood lipids, hormonal axis, and (in women and children) irreversible virilization. It is a steroid, not a peptide.

Evidence grade: Strong human.

Oxymetholone (Anadrol)