Anavar (Oxandrolone)

• Oral

Also known as

Detailed mechanism

Oxandrolone is a synthetic DHT-derived anabolic androgenic steroid with 17-alpha-alkylation for oral bioavailability. It binds selectively to androgen receptors (AR) with high affinity, triggering AR translocation to the nucleus and upregulation of anabolic gene programs including IGF-1 expression, nitrogen retention, and myofibrillar protein synthesis. Its DHT backbone confers resistance to aromatization (no estrogen conversion), producing dry, lean anabolic effects without significant estrogenic side effects. The C-2 oxo modification makes it more metabolically stable than testosterone while preserving its anabolic activity, yielding an anabolic-to-androgenic ratio estimated at 3–6x that of testosterone.

Safety profile

Oxandrolone carries hepatotoxicity risk due to 17-alpha-alkylation; liver enzyme elevation (ALT, AST) is dose-dependent and reverses on cessation. It suppresses the hypothalamic-pituitary-gonadal axis, reducing endogenous testosterone production even at clinical doses; post-cycle gonadal recovery can take weeks to months. Lipid profile effects include HDL reduction (often 20–30%) and LDL elevation, raising cardiovascular risk with long-term use. At clinical doses (5–20 mg/day) virilization in women is lower-risk than most AAS but remains dose-dependent. Contraindicated in liver disease, prostate cancer, and pregnancy.

Clinical trials

Oxandrolone received FDA approval in 1964 (NDA 013718) for weight restoration in catabolic states. Key trials include a landmark RCT by Yeh et al. demonstrating lean mass preservation in HIV-associated wasting (NEJM 1996), and burn injury recovery studies showing accelerated rehabilitation in pediatric patients (Annals of Surgery, 2003–2012). Additional approved indications include Turner syndrome in girls and constitutional growth delay. Post-approval studies have evaluated its utility in COPD-related muscle wasting, alcoholic hepatitis, and osteoporosis, with mixed conclusions on the risk-benefit balance in non-approved populations.

Comparison context

Anavar is the mildest oral steroid, significant strength gains with minimal mass, making it popular with female athletes and weight-class competitors. Unlike Dianabol, which blows you up with water, Anavar produces lean, dry gains. Compared to Winstrol, which is harsher on joints and lipids, Anavar is the cleaner option. Primobolan is its injectable cousin for similar goals.