History

Oxandrolone was developed by Searle (later marketed by BTG as Oxandrin) as a 17α-alkylated derivative of dihydrotestosterone, the alkyl group conferring oral bioavailability by resisting first-pass hepatic breakdown. It received FDA approval for adjunctive use in weight gain after surgery, chronic infection, or severe trauma, to offset corticosteroid-induced protein catabolism, and for relief of osteoporotic bone pain. The branded product was later discontinued, though generic oxandrolone remains available by prescription.

Oxandrolone, sold under the brand name Oxandrin and widely known by the name Anavar, is a synthetic anabolic-androgenic steroid (AAS). It is an orally active derivative of dihydrotestosterone, and despite its reputation in fitness circles as a “mild” or “safe” steroid, it carries the full risk profile of an exogenous androgen, including the liver-injury risks tied to its 17α-alkylated structure. It is not a peptide and not a SARM.

What it is

Oxandrolone is a 17α-alkylated derivative of dihydrotestosterone (DHT). The 17α-alkyl group makes it orally bioavailable by resisting first-pass hepatic breakdown. Mechanistically, it is an agonist at the intracellular androgen receptor (AR); the activated AR acts as a transcription factor to promote nitrogen retention and skeletal-muscle protein synthesis (the anabolic effect) alongside androgenic effects. It is marketed as having a relatively high anabolic-to-androgenic ratio, but this is a relative, not absolute, separation — it remains an androgen.

The claims

The FDA-approved label uses (Oxandrin) are as an adjunct to promote weight gain after weight loss following surgery, chronic infection, or severe trauma; to offset the protein catabolism of prolonged corticosteroid use; and for relief of bone pain associated with osteoporosis. Off-label clinical use with genuine trial support includes severe burn recovery, HIV/AIDS-associated wasting, and short stature in Turner syndrome (as an adjunct to growth hormone).

In fitness and biohacking marketing, oxandrolone is promoted for lean muscle gain, “cutting” and fat-loss aesthetics, and strength, with a particular reputation as a “mild” or “safe” oral steroid marketed to women. That “mild/safe” framing is not supported by the evidence.

What the evidence actually shows

The strongest evidence base is in severe burns. Multiple randomized controlled trials support oxandrolone for preserving lean body mass and improving outcomes. Wolf et al. (2006), a multicenter RCT in severely burned adults, found shorter length of stay versus placebo (PMID 16566555). Studies in burned children showed lean-mass and muscle benefit, including in combination with exercise (Przkora/Herndon/Suman 2007, PMID 17130281; Hart et al. 2001, PMID 11303139). A 2025 systematic review and meta-analysis (World Journal of Emergency Surgery, doi:10.1186/s13017-025-00648-w) found reduced surgical burden and shorter length of stay.

For HIV-associated weight loss/wasting, RCTs show dose-dependent gains in body weight and body cell mass — Berger et al. (1996) in 63 men with AIDS-wasting myopathy (PMID 8970686), and Grunfeld et al. (2006), a large RCT of 262 men showing dose-dependent weight and body-cell-mass gains (PMID 16540931). Effect size is moderate, since placebo groups also gained some weight in some trials.

For Turner syndrome short stature, RCT evidence supports a modest adult-height gain when oxandrolone is added to growth hormone. The UK randomized placebo-controlled trial final analysis (Gault et al. 2021, Arch Dis Child) found roughly a 4.1 cm final-height increase (PMID 31862699), and a meta-analysis confirms a positive but modest pooled effect of about 2.1 cm (PMID 26322078 / PMC4551522).

For performance or aesthetic enhancement in healthy people, there is little rigorous, high-quality RCT evidence specifically validating oxandrolone for recreational physique or performance goals. The clinical literature sits in catabolic-illness populations, not healthy athletes, and claims of being uniquely “safe” are marketing rather than trial-derived.

Legal and regulatory status

In the United States, anabolic steroids — including oxandrolone — are Schedule III controlled substances under the Anabolic Steroids Control Act of 1990 (and 2004 amendments). Distribution or possession without a valid prescription is illegal. Oxandrolone is a prescription medicine, not an over-the-counter or supplement product; products sold online as “Anavar” outside the prescription system are unregulated and frequently adulterated or mislabeled.

In sport, oxandrolone is prohibited at all times (in and out of competition) as an exogenous anabolic androgenic steroid under WADA class S1.1a (Anabolic Agents → AAS). It is one of the more frequently detected AAS in doping cases. (SARMs sit under S1.2; oxandrolone is an actual steroid under S1.1, not S1.2.)

Safety

The “mild oral steroid” reputation does not exempt oxandrolone from real androgen and 17α-alkyl risks.

HPG-axis suppression: As an exogenous androgen, it suppresses endogenous testosterone and gonadotropins (LH/FSH), and can cause testicular atrophy and impaired spermatogenesis in men. In women it can cause virilization (voice deepening, hirsutism, clitoromegaly), some of which is irreversible.
Hepatotoxicity: Its 17α-alkylated structure is the feature associated with liver injury. Documented signals include elevated transaminases, cholestatic and hepatocellular injury, and — with prolonged or high exposure — peliosis hepatis and hepatic adenomas/tumors (NIH LiverTox). The 2025 burn meta-analysis specifically flagged elevated hepatotoxicity risk in adults.
Lipids and cardiovascular: It reliably lowers HDL and can raise LDL, an atherogenic shift; chronic use raises concern for atherosclerosis, coronary artery disease, MI, and stroke. Lipid changes are generally reversible roughly a month after discontinuation per labeling.
Other label warnings: fluid retention and edema, possible effects on glucose/insulin, prostate effects in older men, and contraindication in pregnancy (teratogenic and virilizing to a female fetus).

No oxandrolone-specific “blindness,” vision-tint, QT-prolongation, or carcinogenicity signals are asserted here — those map to other agents (such as the SARMs andarine and GW-501516) and are not attributes of oxandrolone.

Bottom line

Oxandrolone has a genuine, high-quality human evidence base — but for catabolic illness (severe burns, HIV wasting, Turner syndrome), not for recreational physique or performance use, where rigorous evidence is lacking. It is a Schedule III prescription steroid, banned in sport, and carries real androgenic, hepatic, and cardiovascular risks. The popular framing of Anavar as a uniquely “safe” or “mild” steroid is marketing, not science.

Evidence grade: Strong human.

Oxandrolone (Anavar)