Oxandrolone (Anavar)

What oxandrolone is

Oxandrolone is a synthetic steroid that works as a tablet. In the US it was approved in 1964 as Oxandrin: as adjunctive therapy for weight gain after weight loss due to major surgery, chronic infections or severe trauma, against protein breakdown during long-term corticosteroid therapy, and against bone pain in osteoporosis. Effective June 28, 2023, the FDA withdrew the approval of all oxandrolone tablets. In Germany, no product is approved.

This places oxandrolone between nandrolone and trenbolone: there are real clinical trials and almost six decades of medical use, but no approval any more, and the authority that had approved it considers the potential problems serious enough to take it off the market.

How it works

Oxandrolone binds to the androgen receptor and increases protein synthesis in muscle and tissue. So that it works as a tablet, it is chemically modified at carbon atom 17; it is 17α-alkylated. It is precisely this group of steroids that is most closely associated with cholestasis, peliosis hepatis and liver tumors.

Like other androgens, oxandrolone suppresses the hormone axis. In a randomized trial with HIV patients, LH, FSH, the transport protein SHBG and total and free testosterone fell.

What the studies show

Lou 2025: meta-analysis in burn patients

14 randomized trials from the years 2005 to 2025 with 2,822 patients were analyzed. With oxandrolone, fewer operations were needed (standardized mean difference −1.25), and the hospital stay was shorter relative to the burned body surface area; fat-free mass and weight increased more. There was no difference in mortality (relative risk 1.04) or infections. In adults, liver values rose more often, in 19 versus 5 percent. The studies differ greatly from one another, and the authors urge cautious interpretation.

Grunfeld 2006: HIV-related weight loss

262 men with HIV and marked weight loss received placebo or oxandrolone at three dose levels for 12 weeks in a double-blind design. Weight and body cell mass rose in all groups, including on placebo. Weight increased more than on placebo in only one of the three dose groups, body cell mass in two. At the same time, LH, FSH, SHBG and testosterone fell, liver values and LDL rose, and HDL fell.

Schroeder 2004: older men

32 healthy men aged 60 to 87 received oxandrolone or placebo for 12 weeks. Fat-free mass rose by 3.0 kg, thigh muscle increased, strength rose by 5 to 9 percent depending on the exercise, and body fat fell by 1.9 kg; at the same time body water rose by 2.9 kg. Twelve weeks after stopping, fat-free mass and strength were no longer above baseline; the fat loss largely persisted.

Bulger 2004: ventilated patients

41 ventilated surgical and trauma patients received oxandrolone or placebo in a double-blind design. Contrary to expectations, the patients on oxandrolone stayed on the ventilator longer, on average 21.7 versus 16.4 days, and longer in the intensive care unit. The authors suspect that oxandrolone promotes the formation of connective tissue in the lungs.

Gault 2011: Turner syndrome

106 girls with Turner syndrome on growth hormone were randomized; 82 reached final height. Oxandrolone increased it by 4.6 cm compared with placebo. This is a treatment of children under medical supervision and says nothing about adults in training.

Where the data stop

• No study in young, healthy people who train. All data come from sick or injured people, children or older people. For the purpose for which oxandrolone is mostly traded today, there is no controlled study.
• Mass is not the same as benefit. In burn patients, mortality did not fall; in ventilated patients, ventilation was prolonged. An FDA committee found no proof of efficacy in 1984.
• The gain does not last. In older men, mass and strength were back at baseline three months after stopping.
• Mental health and heart not specifically studied. There are no controlled long-term data on psychological effects or cardiac events under oxandrolone. Registry data on steroids as a whole show markedly increased cardiac risks, see anabolic steroids.
• Origin of the products. There is no approved product in Germany, nor in the US since 2023. What is traded comes from the gray market and is not what was tested in the studies.

Status, approval and legal

Oxandrolone was approved as a medicine in the US from 1964 to 2023. An FDA advisory committee concluded unanimously as early as 1984 that there was no proof of efficacy. Effective June 28, 2023, the FDA withdrew the approval of all oxandrolone tablets; the manufacturers had themselves requested the withdrawal after the agency classified the potential problems as serious enough to take the drug off the market.

In Germany, no oxandrolone product is approved; finished medicinal products may only be placed on the market here with an approval (§ 21 German Medicines Act). Oxandrolone is listed by name in the annex of the German Anti-Doping Act: acquiring, possessing and bringing into the country non-small quantities for doping in sport are prohibited, as are trading and supplying for doping purposes. In sport it is on the WADA Prohibited List under S1.1 and is banned at all times.

Safety

Liver: from the prescribing information, the FDA cites peliosis hepatis, that is, blood-filled cavities in the liver, sometimes with liver failure and bleeding into the abdominal cavity, as well as liver cell tumors, sometimes fatal, and cholestatic hepatitis. In the meta-analysis in burn patients, liver values rose in 19 percent of adults, versus 5 percent on placebo. Blood lipids: in the HIV study, HDL fell and LDL rose significantly; according to the FDA, these are changes associated with an increased risk of atherosclerosis. Hormonal: LH, FSH, SHBG and testosterone are suppressed. Further warnings: elevated calcium in breast cancer as well as prostate enlargement and prostate cancer in older people. Mental health: not specifically studied for oxandrolone.

Before any step, a conversation with a physician belongs here, not as a formality but because of effects on the liver and blood vessels that you will not notice yourself.

Sources

• FDA, Federal Register June 28, 2023 – withdrawal of approval of Oxandrin and all oxandrolone tablets
• Lou et al., World J Emerg Surg 2025 – meta-analysis of 14 randomized trials in burn patients
• Grunfeld et al., J Acquir Immune Defic Syndr 2006 – randomized trial in HIV-related weight loss, 262 men
• Schroeder et al., J Appl Physiol 2004 – 32 older men: effects and their persistence after stopping
• Bulger et al., Ann Surg 2004 – ventilated surgical patients: longer ventilation on oxandrolone
• Gault et al., BMJ 2011 – Turner syndrome: final height on oxandrolone, randomized and placebo-controlled
• LiverTox (NIH) – Androgenic Steroids: liver injury from 17α-alkylated steroids
• German Medicines Act (AMG), § 21 marketing authorization requirement
• German Anti-Doping Act (AntiDopG), annex – anabolic-androgenic steroids (oxandrolone)
• Prohibited list in sport: anabolic-androgenic steroids, S1.1 (WADA Prohibited List)