Oxandrolone (Anavar)

Oxandrolone is sold under the brand name Oxandrin and is widely known as Anavar. It’s a man-made anabolic-androgenic steroid (AAS) — a drug that mimics testosterone to build muscle. You can take it as a pill. In fitness circles it has a reputation as a “mild” or “safe” steroid, but that reputation is misleading: it carries all the usual risks of an added male hormone (androgen), including the liver risks that come with its particular chemical design. It is not a peptide, and it is not a SARM.

What it is

Oxandrolone is a tweaked version of dihydrotestosterone (DHT), a natural androgen. The specific tweak — a chemical group called a 17α-alkyl group — lets it survive a first pass through the liver, which is why it works as a pill instead of an injection. Inside your cells it switches on the androgen receptor (the docking point that male hormones act through). Once switched on, that receptor tells the body to hold on to nitrogen and build more muscle protein (the muscle-building, or anabolic, effect), along with the usual male-hormone (androgenic) effects. It’s often marketed as having a high “anabolic-to-androgenic ratio,” meaning more muscle-building for less of the male-hormone baggage. But that’s only a relative difference — it’s still an androgen.

The claims

On its official FDA-approved label (as Oxandrin), it’s meant to help people regain weight they’ve lost after surgery, a long infection, or serious injury; to counter the muscle-wasting caused by long-term steroid medicines like prednisone; and to ease bone pain from osteoporosis. Beyond the label, doctors have used it for a few conditions where real clinical trials back it up: recovering from severe burns, the wasting (severe weight and muscle loss) that can come with HIV/AIDS, and short stature in Turner syndrome (a genetic condition in girls), where it’s added on top of growth hormone.

In the fitness and biohacking world, oxandrolone gets promoted for lean muscle, “cutting” and a leaner look, and strength — and it’s especially marketed to women as a “mild” or “safe” oral steroid. The evidence does not back up that “mild/safe” framing.

What the evidence actually shows

The strongest evidence is in severe burns. Several randomized controlled trials (the gold-standard study type, where people are randomly assigned to the drug or a dummy treatment) support oxandrolone for protecting lean body mass and improving recovery. Wolf et al. (2006), a study run across multiple hospitals in badly burned adults, found patients spent less time in the hospital than those given a placebo (PMID 16566555). Studies in burned children showed gains in lean mass and muscle, including when combined with exercise (Przkora/Herndon/Suman 2007, PMID 17130281; Hart et al. 2001, PMID 11303139). A 2025 review that pooled the results of many studies (a systematic review and meta-analysis, in the World Journal of Emergency Surgery, doi:10.1186/s13017-025-00648-w) found less need for surgery and shorter hospital stays.

For HIV-related weight loss and wasting, trials show that bigger doses lead to bigger gains in body weight and body cell mass (the active, working tissue in your body) — Berger et al. (1996) in 63 men with AIDS-wasting myopathy (PMID 8970686), and Grunfeld et al. (2006), a large trial of 262 men showing dose-dependent weight and body-cell-mass gains (PMID 16540931). The benefit is moderate, partly because in some trials the placebo groups also gained some weight.

For short stature in Turner syndrome, trials support a modest gain in adult height when oxandrolone is added to growth hormone. The final results of a UK placebo-controlled trial (Gault et al. 2021, Arch Dis Child) found roughly a 4.1 cm boost in final height (PMID 31862699), and a meta-analysis that combined trials confirmed a real but modest average effect of about 2.1 cm (PMID 26322078 / PMC4551522).

For performance or looks in healthy people, there’s very little solid, high-quality trial evidence showing oxandrolone actually delivers for recreational physique or performance goals. The good clinical research is in sick patients losing muscle, not in healthy athletes — and the idea that it’s uniquely “safe” comes from marketing, not from trials.

Legal and regulatory status

In the United States, anabolic steroids — oxandrolone included — are Schedule III controlled substances under the Anabolic Steroids Control Act of 1990 (and 2004 amendments). Selling them, or even having them, without a valid prescription is illegal. Oxandrolone is a prescription medicine, not an over-the-counter product or a supplement. Anything sold online as “Anavar” outside the prescription system is unregulated and is often contaminated or mislabeled (you can’t trust the label).

In sport, oxandrolone is banned at all times — both in and out of competition — as an added anabolic androgenic steroid under WADA class S1.1a (Anabolic Agents → AAS). It’s one of the steroids caught most often in doping cases. (For the record, SARMs fall under a different category, S1.2; oxandrolone is a true steroid under S1.1, not S1.2.)

Safety

The “mild oral steroid” reputation doesn’t get oxandrolone off the hook for the real risks of androgens and 17α-alkyl drugs.

• HPG-axis suppression: Because it’s an added male hormone, it tells the body to dial back its own testosterone and the hormones that drive it (LH and FSH). In men this can shrink the testicles and lower sperm production. In women it can cause masculinizing changes (virilization) — a deeper voice, extra body hair (hirsutism), and an enlarged clitoris (clitoromegaly) — some of which don’t reverse.
• Hepatotoxicity (liver harm): The same 17α-alkyl design that makes it work as a pill is what’s linked to liver injury. Documented warning signs include raised liver enzymes (transaminases), backed-up bile and direct liver-cell damage, and — with long or heavy use — blood-filled cysts in the liver (peliosis hepatis) and liver tumors, both benign and cancerous (NIH LiverTox). The 2025 burn meta-analysis specifically flagged a higher risk of liver harm in adults.
• Lipids and heart: It reliably drops HDL (“good” cholesterol) and can raise LDL (“bad” cholesterol), a shift that clogs arteries; over time this raises concern for hardened arteries, coronary artery disease, heart attack, and stroke. According to the label, the cholesterol changes generally reverse about a month after stopping.
• Other label warnings: holding on to fluid and swelling (edema), possible effects on blood sugar and insulin, prostate effects in older men, and a clear no-go in pregnancy (it can harm a developing baby and masculinize a female fetus).

To be clear, there are no oxandrolone-specific reports of blindness, a vision tint, QT prolongation (a heart-rhythm risk), or cancer from the drug itself — those belong to other compounds (like the SARMs andarine and GW-501516) and are not features of oxandrolone.

Bottom line

Oxandrolone does have a real, high-quality body of human evidence — but it’s for catabolic illness (severe burns, HIV wasting, Turner syndrome), not for recreational muscle-building or performance, where solid evidence is missing. It’s a Schedule III prescription steroid, banned in sport, and it carries genuine androgen, liver, and heart risks. The popular image of Anavar as a uniquely “safe” or “mild” steroid is marketing, not science.

Evidence grade: 8/10 · Good.

Sources

• FDA Oxandrin label (oxandrolone tablets, USP)
• NIH LiverTox — Androgenic/Anabolic Steroids
• StatPearls — Anabolic Steroids (NCBI Bookshelf)
• Wolf SE et al. 2006 — oxandrolone in severely burned, multicenter RCT (PMID 16566555)
• Przkora R, Herndon DN, Suman OE 2007 — oxandrolone + exercise in burned children (PMID 17130281)
• Hart DW et al. 2001 — anabolic effects of oxandrolone after severe burn (PMID 11303139)
• Oxandrolone for burn patients, 2025 systematic review/meta-analysis (World J Emerg Surg)
• Berger JR et al. 1996 — oxandrolone in AIDS-wasting myopathy (PMID 8970686)
• Grunfeld C et al. 2006 — oxandrolone in HIV-associated weight loss in men, RCT (PMID 16540931)
• Gault EJ et al. 2021 — UK Turner syndrome RCT, oxandrolone effect on final height (PMID 31862699)
• Meta-analysis — oxandrolone + GH on adult height in Turner syndrome (PMID 26322078 / PMC4551522)
• WADA Prohibited List (oxandrolone under S1.1 Anabolic Androgenic Steroids)