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Oxandrolone (Anavar, Oxandrin) — oral 17α-alkylated anabolic-androgenic steroid; DEA Schedule III controlled substance
A prescription oral anabolic-androgenic steroid (AAS) — brand Anavar/Oxandrin — and a DEA Schedule III CONTROLLED SUBSTANCE. It has genuine randomized-trial evidence in formerly FDA-approved (withdrawn June 2023), supervised muscle-wasting settings: it adds lean body mass, speeds wound healing and shortens hospital stay in severe burns, raises body weight in HIV-associated wasting, and modestly increases adult height in Turner syndrome. But it is 17α-alkylated and hepatotoxic (dose-related transaminase rises, cholestasis, and — with anabolic steroids generally — peliosis and liver tumours), it sharply lowers HDL and raises LDL cholesterol, and it suppresses the hypothalamic-pituitary-testicular axis and virilizes. It is NOT a dietary supplement and NOT a longevity drug; non-medical bodybuilding use is unsupervised and carries real liver, lipid, and endocrine harm. Described for harm-reduction information only — not a recommendation.
Prescription medication — not a dietary supplement
Oxandrolone (Anavar) is a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Oxandrolone (Anavar) doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1976–2025 with a typical study size of 133 participants.
Based on 86 studies · 5 meta-analyses · 74 RCTs · 199 total participants
Confidence
High confidenceBy outcome
Oxandrolone has genuine randomized-trial evidence in its formerly FDA-approved (withdrawn June 2023), supervised muscle-wasting indications — a multicenter burns RCT and a 15-RCT meta-analysis show shorter hospital stay, faster wound healing and added lean body mass; RCTs show weight gain in HIV wasting and modest adult-height gain in Turner syndrome. But it is a 17α-alkylated, hepatotoxic, DEA Schedule III controlled substance: dose-related transaminitis (42% in one burn-unit series), cholestasis/peliosis/liver-tumour risk for AAS as a class, an adverse HDL/LDL shift, HPTA suppression and virilization. It is not a current US prescription product (approval withdrawn in 2023), not a dietary supplement and not a longevity drug, and non-medical bodybuilding use is unsupervised — so it sits in the low-mid range, weighted up by real RCTs in its former approved indications and down hard by the harms and legal status.
81 randomised trials
94% were about Oxandrolone (Anavar) in an audit of 50 of them
Every randomised or controlled trial of Oxandrolone (Anavar) indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Sep 2026
1 trial ongoing or recruiting · 13 completed on ClinicalTrials.gov
2 of the completed trials have posted results
Registered trials show research momentum for Oxandrolone (Anavar), not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Nov 2026
Under EU law (Reg. 1924/2006), EFSA reviews whether a specific health claim for Oxandrolone (Anavar) meets the evidence standard. These are independent regulatory decisions on claims — not studies, and never counted toward the evidence score above.
“Not authorised” means the specific claim wording did not meet the EU’s evidence standard — often a matter of dossier or phrasing, not proof of no effect. EFSA judges marketing claims and is kept separate from our study-based evidence score.
Source: EU Register of nutrition and health claims (European Commission / EFSA) · register snapshot Feb 2013
Oxandrolone (brand names Anavar and Oxandrin) is an oral 17α-alkylated anabolic-androgenic steroid (AAS) — a synthetic derivative of testosterone, structurally modified at the 17-alpha position so it survives first-pass metabolism and can be taken by mouth.
It was a prescription drug in the United States until FDA withdrew its approval in June 2023, and it is a Schedule III controlled substance under the Controlled Substances Act; possession or distribution without a valid prescription is a federal crime.
It was FDA-approved, until the approval was withdrawn in June 2023, as adjunctive therapy to promote weight gain after surgery, chronic infection, severe trauma, and certain cases of weight loss, and to offset the protein catabolism of prolonged corticosteroids — narrow, supervised, muscle-wasting indications, not body composition or athletics.
Unusually for the compounds in this collection, oxandrolone has real randomized-controlled-trial evidence in its formerly approved settings.
In severe burns it is the best-studied: a multicenter, double-blind RCT in adults (Wolf 2006) found oxandrolone 10 mg twice daily shortened length of hospital stay versus placebo — the trial was stopped early at interim analysis for benefit — while a randomized trial in severely burned children (Przkora/Herndon 2007) showed gains in lean body mass and strength, and a systematic review and meta-analysis of 15 RCTs in 806 burn patients (Li 2016) found oxandrolone shortened length of stay and donor-site healing time, reduced weight and nitrogen loss in the catabolic phase, and added roughly 4% lean body mass at 6 months and ~11% at 12 months.
In HIV-associated weight loss, a randomized, double-blind, placebo-controlled trial in 262 men (Grunfeld 2006) showed dose-dependent gains in body weight and body cell mass.
In Turner syndrome, a randomized, double-blind trial (Menke 2010) found that adding low-dose oxandrolone to growth hormone modestly increased adult height — though the conventional dose was discouraged because of accelerated bone maturation and virilization.
There is also a historic alcoholic-hepatitis RCT (Mendenhall, NEJM 1984) in which oxandrolone did not improve short-term survival but was associated with improved long-term survival in moderate disease. So the anabolic and catabolism-sparing signal in its formerly approved, supervised indications is real.
The honest counterweight defines the compound.
Because it is 17α-alkylated, oxandrolone is hepatotoxic: dose-related rises in hepatic transaminases are its most common adverse effect (the Wolf burns trial concluded it should be used 'while hepatic transaminases are monitored'; a retrospective burn-unit analysis (Kiracofe 2019) found transaminitis in 42% of treated patients), and anabolic-androgenic steroids as a class are associated with cholestasis, peliosis hepatis, hepatic adenoma, and hepatocellular carcinoma (Solimini 2017).
It worsens the lipid profile — the HIV trial documented significant rises in LDL and falls in HDL cholesterol on treatment — and it suppresses the hypothalamic-pituitary-testicular axis (suppressed LH, FSH, SHBG, and total and free testosterone) and causes virilization (deepened voice, hirsutism, menstrual changes) that can be irreversible in women.
The score reflects genuine, randomized evidence in formerly approved muscle-wasting indications set against documented hepatotoxicity, an adverse lipid shift, HPTA suppression and virilization, plus the reality that this is a controlled substance, not a supplement, and that non-medical use for body composition carries those same harms without medical monitoring.
Oxandrolone is a synthetic testosterone derivative that binds and activates the androgen receptor in skeletal muscle and other tissues, driving the anabolic, protein-sparing signalling that underlies its weight-gain and muscle-wasting indications.
Androgen-receptor activation increases net protein balance and lean body mass and reduces catabolic nitrogen loss — the mechanism behind the lean-mass gain, faster donor-site/wound healing and shorter hospital stay measured in burn trials.
The 17α-alkyl group that makes oxandrolone orally active also makes it hepatotoxic (transaminitis, cholestasis, and — for AAS broadly — peliosis and liver tumours). The same androgenic activity lowers HDL and raises LDL cholesterol, suppresses the hypothalamic-pituitary-testicular axis, and virilizes.
How Oxandrolone (Anavar) works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Avoid — a controlled substance whose US approval was withdrawn in 2023, not a supplement; documented hepatotoxicity, adverse lipids, HPTA suppression and virilization, and not for self-experimentation.
High caution even when prescribed — virilizing effects (voice deepening, hirsutism, clitoral enlargement) can be permanent; discontinue at the first androgenic sign.
Major interaction — requires clinician-managed anticoagulant dose reduction and frequent INR checks.
Avoid entirely — androgenic; causes fetal virilization.
Oxandrolone markedly potentiates warfarin, raising INR and bleeding risk; anticoagulant doses often need substantial reduction with close INR monitoring under a clinician.
Oxandrolone is itself hepatotoxic; combining it with other hepatotoxic agents or alcohol compounds the risk of transaminitis and cholestatic injury.
Anabolic steroids can improve insulin sensitivity and lower glucose, potentially requiring antidiabetic-dose adjustment.
Stacking androgenic agents compounds hepatic burden, HPTA suppression and the adverse lipid shift; the combined risk is additive and uncharacterised in non-medical use.
Tip: Its most common adverse effect — dose-related liver-enzyme rises (42% in one burn-unit series). Approved use requires periodic transaminase monitoring; stop and seek care for jaundice, dark urine or right-upper-quadrant pain.
Tip: Anabolic-androgenic steroids as a class are linked to peliosis hepatis, hepatic adenoma and hepatocellular carcinoma; risk rises with prolonged or high-dose use. There is no safe self-monitoring framework for non-medical use.
Tip: Lowered HDL and raised LDL cholesterol are consistent on treatment and work against cardiovascular health; reversibility depends on discontinuation.
Tip: Suppresses LH, FSH, SHBG and endogenous testosterone, and virilizes — deepened voice, hirsutism, menstrual disruption and clitoral enlargement in women may be irreversible. Stop at the first sign of voice change in women.
Oxandrolone (Anavar) has an evidence score of 4.7/10 — emerging evidence based on 86 indexed studies, including 1 meta-analysis. A prescription oral anabolic-androgenic steroid (AAS) — brand Anavar/Oxandrin — and a DEA Schedule III CONTROLLED SUBSTANCE. It has genuine randomized-trial evidence in formerly FDA-approved (withdrawn June 2023), supervised muscle-wasting settings: it adds lean body mass, speeds wound healing and shortens hospital stay in severe burns, raises body weight in HIV-associated wasting, and modestly increases adult height in Turner syndrome. But it is 17α-alkylated and hepatotoxic (dose-related transaminase rises, cholestasis, and — with anabolic steroids generally — peliosis and liver tumours), it sharply lowers HDL and raises LDL cholesterol, and it suppresses the hypothalamic-pituitary-testicular axis and virilizes. It is NOT a dietary supplement and NOT a longevity drug; non-medical bodybuilding use is unsupervised and carries real liver, lipid, and endocrine harm. Described for harm-reduction information only — not a recommendation. Representative study: PMID 26454425.
Dosing for Oxandrolone (Anavar): No self-directed dose is recommended by SupStack. Oxandrolone is a prescription-only, DEA Schedule III controlled substance; this library does NOT provide a body-composition dosing protocol. For context only: the former US label for muscle wasting (the approval was withdrawn in June 2023) gave 2.5–20 mg/day in divided doses under a physician, and trials used 10 mg twice daily in adult burns, 0.1 mg/kg/day in burned children, 20–80 mg/day in HIV wasting, and 0.03–0.06 mg/kg/day with growth hormone in Turner syndrome — all clinician-supervised with liver and lipid monitoring. That is not an endorsement of self-administration.
Timing is flexible for Oxandrolone (Anavar) — consistent daily use matters more than the time of day. Approved use is divided doses through the day under medical supervision with liver-enzyme and lipid monitoring.
No consumer dose of Oxandrolone (Anavar) is endorsed, so there is no dose at which it can be called safe. Talk to a healthcare provider before taking it. Reported side effects include peliosis hepatis / hepatic tumour (AAS class), hepatic transaminitis / cholestatic liver injury, adverse lipid shift (low HDL, high LDL), HPTA suppression & virilization. How often they occur is not established for all of them. Use caution if any of these apply to you: Anyone seeking it for body composition or athletic performance without a prescription — a DEA Schedule III controlled substance; it is not a dietary supplement, and laws on supply, possession, import and use depend on the country and circumstances; Pre-existing liver disease or elevated liver enzymes — 17α-alkylated and hepatotoxic (transaminitis, cholestasis, peliosis); Known or suspected prostate or male breast carcinoma; hypercalcemia.
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
Epicatechin
Mixed evidenceDark chocolate flavanol with consistent human evidence for improved endothelial function and modest blood pressure reduction. Muscle-building claims are not supported in humans.
Collagen
Likely helpsHydrolyzed peptides that rebuild skin elasticity, reduce joint pain, and strengthen bone density — results build over 8-12 weeks.
MSM
Too few graded studiesOrganic sulfur donor for connective tissue repair — reduces joint inflammation and supports post-exercise recovery and flexibility.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 86 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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