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Oxandrolone (Anavar): medical history, research and risks
Educational information, not personal medical advice. AI-assisted research and editorial preparation by AnabolicRX. Sources checked 23 October 2026. No independent clinical review has been completed. This library is associated with a supplies store; it does not sell steroids or provide instructions for nonmedical use.
Identity: a name is not a safety category
Oxandrolone is an anabolic-androgenic steroid, also encountered under the historical brand names Anavar and Oxandrin. Its anabolic effects concern tissue-building processes; androgenic effects concern sex-hormone activity. These are not completely separable properties. The historical US label specifically cautioned that separating anabolic from androgenic effects had not been achieved. Calling a drug “mild” therefore does not describe its full risk profile. Historical Oxandrin prescribing information, 2005
The brand alias here helps readers recognize terminology. It is not an authentication guide for products carrying that name, and no products are offered through this educational profile.
Medical history and the change in US status
Oxandrin's original US approval dates to 1964. Historical indications included helping regain weight after certain illnesses or injuries, countering corticosteroid-related protein breakdown and relieving osteoporosis-related bone pain. In 2023, FDA withdrew approval; its September determination states that withdrawal was for safety or effectiveness reasons. The notice discusses serious liver and lipid concerns and the agency's assessment of the evidence. An old approved label should consequently be read as a historical document, not proof of present US authorization. FDA determination, Federal Register, 13 September 2023
This distinction also matters when reading an older scientific paper. A study remains part of the evidence record after a regulatory change, but its existence does not reverse that change or establish that the overall balance of benefits and harms is favourable today.
How researchers investigated its effects
A mechanistic study examined muscle protein handling in 26 children after severe burns, using stable-isotope measurements. The investigators studied whether oxandrolone changed the response to amino-acid provision during recovery. This is a useful example of the difference between a biological mechanism and an outcome a patient experiences: a measurement of protein turnover can help explain an effect, but cannot by itself prove better long-term health, independence or survival. Muscle protein-turnover study, 2011
Disease context is central to interpreting anabolic research. The studies discussed below concern major burns, significant illness-associated weight loss or a defined chromosomal condition. They do not describe interchangeable versions of ordinary exercise recovery.
Human evidence: benefits within specific populations
Recovery after severe burns in children
A single-centre randomized trial followed 222 children with burns affecting more than 30% of body surface area. Seventy received oxandrolone and 152 received placebo. Follow-up extended to five years after injury. Investigators reported improvements in height and bone mineral content; lean mass and strength benefits were reported with an exercise programme. No harmful effects were attributed to treatment in that study.
These findings help explain the clinical interest in burn rehabilitation. They do not establish that rare harms are absent: a study with 70 treated participants has limited ability to detect uncommon outcomes. Its specialist-care setting, age group and severity of injury also limit generalization to adults or healthy people. Porro and colleagues, Journal of the American College of Surgeons, 2012
Bone measurements are not the same as fewer fractures
A later single-centre randomized study included 119 severely burned children and followed growth and bone measurements for five years. Oxandrolone was associated with improvements in bone mineral content, bone density and height velocity. The publication discusses implications for future fracture risk, but the reported outcomes are principally measurements of bone and growth. A reader should not translate them into a proven reduction in fractures without a study measuring that outcome. The trial is also not evidence for treating routine osteoporosis in adults. Reeves and colleagues, Shock, 2016
Illness-associated weight loss in men with HIV
A randomized placebo-controlled trial enrolled 262 men with HIV-associated weight loss or low body mass index. During the blinded period, weight increased in every group, including placebo. Only some oxandrolone groups improved particular weight or body-cell-mass outcomes more than placebo. The investigators also observed suppression of reproductive hormones, increased liver enzymes, higher LDL cholesterol and lower HDL cholesterol.
The comparison with placebo is essential. Improvement from baseline alone does not establish a drug effect when the comparison group improves too. This older trial also reflects its treatment era and population; it does not establish oxandrolone's role within current HIV care or support use in people without wasting illness. Grunfeld and colleagues, JAIDS, 2006
Turner syndrome: a specific growth question
The final analysis of a UK randomized trial assessed 92 girls with Turner syndrome who had also received growth hormone. The estimated difference in final height associated with oxandrolone was 4.1 cm, with a 95% confidence interval of 1.6–6.6 cm. That is evidence about a particular intervention in a defined condition, not a general claim that oxandrolone makes children taller.
Whether an intervention is appropriate today requires current specialist guidance, safety assessment and regulatory context in addition to a historic trial result. This profile does not supply a paediatric treatment recommendation. Gault and colleagues, Archives of Disease in Childhood, 2021; published online 2019
Newer adult burn evidence changes the interpretation
The 2024 RE-ENERGIZE secondary analysis used data from 1,200 severely burned adults. Although the parent trial randomized glutamine, receipt of oxandrolone was not randomized. Greater oxandrolone exposure was associated with slower discharge alive, while adjusted analyses did not find a significant association with in-hospital or six-month mortality. Residual confounding, treatment selection and missing muscle-function endpoints limit causal interpretation. It would be incorrect to describe this as a randomized oxandrolone trial or as proof that the medicine caused a worse outcome. Full report, methods, results and limitations
A 2026 MASCOTS conference report included 527 adults. Its matched comparison did not detect a significant difference in the specified inpatient weight-loss outcome between pooled anabolic-treatment recipients and controls. That pooled, observational result cannot establish that oxandrolone and testosterone are individually equivalent or ineffective. A later journal record was located but its full results remain unverified; the conference report is not treated as an independent second cohort. Conference report Later journal record
Risks: several systems need attention
Liver
The FDA's 2023 notice identifies serious concerns including blood-filled liver lesions known as peliosis hepatis, liver tumours and cholestatic hepatitis. Some of these problems can be severe. These are not adequately summarized by the idea that a tablet is convenient or that an agent has a comparatively favourable reputation. FDA determination, 2023
In a multicentre retrospective study of 309 oxandrolone-treated adult burn patients, 128 developed elevated transaminases under the study definition. The study associated some concurrent medicines and patient characteristics with this outcome. Because it was observational and involved seriously ill people, the 41.4% figure is not an individual risk estimate for another population, nor does it establish how much was independently caused by oxandrolone. It does demonstrate why reports of reassuring findings from one study cannot close the liver-safety question. Kiracofe and colleagues, Journal of Burn Care & Research, 2019
Cardiovascular and metabolic health
The HIV trial's adverse lipid changes are clinically relevant safety signals. A study measuring cholesterol cannot establish the exact long-term probability of heart attack or stroke for a particular person. Conversely, lack of such an outcome in a short trial cannot establish protection from it. Grunfeld and colleagues, 2006
Hormones, growth, pregnancy and fluid balance
The historical label warns about suppression of endogenous hormone function, virilization that can be irreversible, fetal harm, accelerated bone maturation and fluid retention. People with cardiac, kidney or liver disease may be especially vulnerable to complications of fluid retention. These warnings make “safe for women” or “safe because studied in children” poor summaries of the evidence. Historical Oxandrin label, 2005
Interactions
The historical label highlights a potentially substantial interaction with warfarin, affecting clotting measurements and bleeding risk. Corticosteroids or ACTH may increase fluid retention when used concurrently. This is a reason for a complete medication review, not for a reader to adjust medicines independently. Historical Oxandrin label, 2005
Canadian context and unresolved questions
Oxandrolone is named in Schedule IV, item 23, of Canada's Controlled Drugs and Substances Act. Classification is distinct from a product's authorization and market status. This review has not verified a currently authorized Canadian oxandrolone product, and it does not claim that none exists. Department of Justice, Schedule IV
Health Canada identifies oxandrolone among anabolic steroids encountered in bodybuilding products and explains that authorized prescription products carry a Drug Identification Number. A name, professional-looking package or online testimonial does not substitute for checking an actual regulatory record. Health Canada, Using bodybuilding products
What this evidence can and cannot tell us
There is real clinical research here, including randomized studies with meaningful findings in selected patients. There are also important harms, regulatory changes and unanswered questions. A useful profile keeps those facts together. Neither dismissing every study nor treating every favourable result as a general endorsement gives readers a reliable account.
Scope and limitations
Current Canadian product authorization has not been established here. Historical labels and foreign approvals are identified as such. Some evidence was checked at abstract level; where full results were unavailable, no additional findings are inferred. The article is not a current treatment guideline or a complete account of all possible adverse effects.