Oxymesterone is an oral anabolic-androgenic steroid (AAS). Chemically it is 4-hydroxy-17α-methyltestosterone: methyltestosterone with one extra hydroxyl (-OH) group at carbon 4. It was used in Europe in the early 1960s under the brand name Oranabol, and Italian and French reports from 1961 describe it as a new oral anabolic agent.
Oxymesterone is easy to confuse with two better-known oral steroids with similar names. It is not fluoxymesterone (Halotestin), which carries a fluorine atom at carbon 9 and a hydroxyl at carbon 11. It is also not oxymetholone (Anadrol). The three are separate drugs with separate entries on the US controlled-substance list.
The single most important fact is how little is known. We found no randomized controlled trial of oxymesterone in PubMed, no FDA label and no published human half-life. Most of the modern literature on it comes from anti-doping laboratories. This page summarizes what that literature and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | 17α-methylated anabolic-androgenic steroid (4-hydroxy derivative of methyltestosterone) |
| Chemical name | 4,17β-dihydroxy-17α-methylandrost-4-en-3-one |
| Formula / weight | C₂₀H₃₀O₃, 318.4 g/mol (PubChem) |
| Trade names | Oranabol; PubChem also lists Theranabol among synonyms |
| Route | Oral |
| Human half-life | Not reported in any source we found |
| Human trials | No randomized controlled trials found; only uncontrolled 1960s reports |
| US status | No FDA approval record (Drugs@FDA, DailyMed); Schedule III anabolic steroid |
| WADA status | Prohibited at all times (S1.1 anabolic androgenic steroid, non-Specified) |
What it is
PubChem records oxymesterone (CID 72061) as C₂₀H₃₀O₃ with a molecular weight of 318.4 g/mol (PubChem). The US Schedule III list names it as “oxymesterone (17α-methyl-4,17β-dihydroxyandrost-4-en-3-one)” (21 CFR 1308.13).
Its two changes from testosterone each have a known role:
| Change vs testosterone | What it does |
|---|---|
| 17α-methyl group (shared with methyltestosterone) | Blocks oxidation of the 17β-hydroxyl group during first-pass metabolism in the liver, which makes the steroid active by mouth. Liver toxicity is tied to this 17α-alkylated class (Kicman, Br J Pharmacol 2008). |
| 4-hydroxy group on the A-ring | The feature that makes it oxymesterone. The same 4-hydroxy group without the 17α-methyl group gives 4-hydroxytestosterone, which US law lists as a separate Schedule III steroid. |
Like other AAS, oxymesterone is assumed to act through the androgen receptor. We found no published receptor-binding study and no human data on whether it converts to estrogen, so we make no claims about either.
Not the same as fluoxymesterone or oxymetholone
The names differ by a few letters, but the molecules are different. The chemical names below are from the US Schedule III list:
| Steroid | Chemical name (21 CFR 1308.13) | Key difference from methyltestosterone |
|---|---|---|
| Oxymesterone | 17α-methyl-4,17β-dihydroxyandrost-4-en-3-one | Adds a 4-hydroxy group |
| Fluoxymesterone (Halotestin) | 9-fluoro-17α-methyl-11β,17β-dihydroxyandrost-4-en-3-one | Adds a 9-fluoro and an 11β-hydroxy group |
| Oxymetholone (Anadrol) | 17α-methyl-2-hydroxymethylene-17β-hydroxy-5α-androstan-3-one | A 5α-reduced (DHT-based) skeleton with a 2-hydroxymethylene group |
| Methyltestosterone | 17α-methyl-17β-hydroxyandrost-4-en-3-one | Parent compound |
Fluoxymesterone was an FDA-approved US drug with a label and clinical data. Oxymesterone never was, so information from the Halotestin label does not carry over to it.
About anabolic:androgenic ratios. Rat bioassays from the 1950s–1970s compared the growth of a muscle (the levator ani) with the growth of the prostate or seminal vesicles. In a table drawn from that older work, oral oxymesterone had 1.34 times the myotrophic (muscle-building) activity of oral methyltestosterone and 0.42–0.61 times its androgenic activity, for an index of 2.2–3.2 (Kicman, Br J Pharmacol 2008). These are rat figures. The same review describes the many flaws of this index. They do not show what oxymesterone does in people. A 1963 paper reported anabolic-to-androgenic ratios for oxymesterone, fluoxymesterone and two other steroids (Arnold et al., J Endocrinol 1963), but we could not access its data.
How it works in the body
No study we found reports oxymesterone’s half-life, peak blood levels or oral bioavailability in humans. What is known comes from urine studies done to improve doping tests:
| Study | Design | Main findings |
|---|---|---|
| Schänzer et al., Steroids 1992 | Excretion studies with 12 different 17α-methyl steroids, oxymesterone among them | 17α-methyl steroids are partly converted to their 17-epimers (mirror-image forms at carbon 17). How much depends on the A-ring structure. |
| Yang et al., Drug Test Anal 2016 | Human liver cells in culture, plus a single 20 mg oral dose in 2 men | Besides the known metabolite 17-epioxymesterone, found 7 new metabolites. Routes: 4-ene reduction, 3-keto reduction, 11β-hydroxylation and 16-hydroxylation. The parent steroid was not detectable; two new metabolites extended detection up to 4 days. |
| Polet et al., Drug Test Anal 2017 | Human urine after oxymesterone administration, GC-CI-MS/MS | A new long-term metabolite, 18-nor-17β-hydroxymethyl-17α-methyl-4-hydroxy-androst-4,13-diene-3-one, was detectable for up to 46 days. The traditional 17-epioxymesterone screen detected use for only 3.5 days. |
| Kratena et al., Steroids 2020 | Chemical synthesis | Made a reference standard of this long-term metabolite (“Oxy M9”), along with one for the oral Turinabol metabolite M4 |
Two practical points follow from these studies:
- Detection windows vary widely with the test method. The same use was visible for 3.5 days with an older screen and for up to 46 days with the long-term metabolite.
- The same long-term metabolite pattern appears in related steroids. The 18-nor-17-hydroxymethyl structure is also the basis of long-term detection of oral Turinabol, and one paper made reference standards for both through a common synthetic route.
Former medical use
Oxymesterone appears in the medical literature from 1961, mostly in Italian and French journals. The titles of these early reports describe:
- treatment of “osseous atrophy” (bone loss) with Oranabol, including its “protein-anabolic” effect (Quaini, Minerva Med 1961; Quaini and Valobra, Minerva Ortop 1961);
- use in a patient after surgery (Cala, Minerva Chir 1961);
- its introduction as a “new oral anabolic steroid” (Mirouze, Sem Hop 1961);
- blood cholesterol changes during long-term treatment with it and other anabolic steroids (Zeneroli, Endocrinol Sci Cost 1970).
None of these papers has an English abstract in PubMed, and none is described as a controlled trial. We could not review their doses or results, so we do not report any. No regulator has published a label, approved dose or approved indication for oxymesterone that we could find. We found no FDA application for it in Drugs@FDA and no label on DailyMed. A 1993 Australian report noted that it had never been approved in Australia (Kennedy and Lawrence, Med J Aust 1993).
What the research shows
There is almost no outcome research in humans:
- No modern clinical trials. We found no randomized or placebo-controlled trial of oxymesterone on muscle mass, strength, bone or any other outcome.
- Animal potency data only. The only quantitative “anabolic” figures are the rat bioassay ratios described above.
- Human data are metabolic. The human studies since 1990 measured urinary metabolites after small numbers of doses (for example, a single 20 mg dose in 2 men). They were designed to improve drug testing, not to measure benefit or harm.
Claims about oxymesterone’s effects on muscle, strength or endurance therefore have no controlled human evidence behind them.
Side effects and risks
No study has measured oxymesterone’s side effects systematically. The risks below come from its drug class and from case reports. They should be read as likely class effects, not as measured rates for this drug.
Liver
Oxymesterone is a 17α-alkylated oral steroid. A pharmacology review lists these liver effects for the class (Kicman, Br J Pharmacol 2008):
- cholestasis (blocked bile flow) with jaundice;
- peliosis hepatis (blood-filled cysts in the liver);
- an increased risk of liver tumors.
The same review notes that hepatotoxicity is associated with the 17α-alkylated, orally active steroids in particular.
Heart and blood lipids
The same review links AAS misuse to lower HDL (“good”) cholesterol, higher LDL cholesterol, a raised hematocrit (the share of blood made up of red cells), left ventricular hypertrophy (thickening of the heart’s main pumping chamber) and sudden cardiac death.
The only case reports naming oxymesterone describe two Australian footballers, aged 18 and 24, who died of cardiac arrest during training (Kennedy and Lawrence, Med J Aust 1993). Both men’s urine contained oxymesterone:
| Case | Age | Autopsy finding | Coronary arteries |
|---|---|---|---|
| 1 | 18 | Features of hypertrophic cardiomyopathy | Normal |
| 2 | 24 | Myocarditis (heart muscle inflammation) | Normal |
The authors wrote that a causal relationship is hard to prove. They suggested the steroid may have contributed to heart enlargement in the first man and to a rhythm disturbance in both.
Hormonal and other class effects
Kicman’s review also lists class effects that apply to AAS in general (Kicman, Br J Pharmacol 2008):
- suppression of the body’s own testosterone production;
- in women: deeper voice, unwanted body and facial hair, clitoral enlargement and menstrual changes, some of which may not reverse;
- in children and adolescents: early closure of the growth plates and stunted height;
- acne and male-pattern hair loss.
No source we found reports how strongly oxymesterone itself causes these effects.
Quality
Because no licensed oxymesterone product is available in the US, anything sold under that name comes from outside the regulated drug supply. Its identity, dose and purity cannot be assumed.
Legal status and use in sport
- United States. Oxymesterone is named in the Schedule III list of anabolic steroids, with its salts, esters and ethers (21 CFR 1308.13).
- Sport. The WADA 2026 Prohibited List names oxymesterone under S1.1 anabolic androgenic steroids. It is prohibited at all times, in and out of competition, and S1 substances are classed as non-Specified.
- Detection. Anti-doping laboratories developed long-term metabolites for oxymesterone because older tests caught use for only a few days (Polet et al., Drug Test Anal 2017).
Key takeaways
- A different drug from Halotestin. Oxymesterone is 4-hydroxy-17α-methyltestosterone. Fluoxymesterone (Halotestin) is the 9-fluoro, 11β-hydroxy analog, and oxymetholone (Anadrol) is a DHT-based steroid. Data for one do not apply to the others.
- An old European oral steroid. It was used as Oranabol from the early 1960s and has no FDA approval record.
- Almost no human evidence. We found no controlled human trials and no published human half-life. The only potency figures are rat bioassay ratios.
- Class risks apply. As a 17α-methylated oral steroid it shares the class’s liver, lipid and hormonal risks. The only case reports naming it involve two fatal cardiac arrests in young athletes.
- Controlled and banned in sport. It is a Schedule III anabolic steroid in the US and is prohibited at all times by WADA. Modern tests can detect a long-term metabolite for up to 46 days.
Sources
- National Center for Biotechnology Information. PubChem Compound Summary for CID 72061, Oxymesterone. PubChem.
- Drug Enforcement Administration. Schedules of controlled substances: Schedule III, 21 CFR 1308.13(f) Anabolic steroids. eCFR.
- World Anti-Doping Agency. The 2026 Prohibited List: International Standard. In effect January 1, 2026. WADA.
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol. 2008;154(3):502–521. PMC.
- Arnold A, Potts GO, Beyler AL. The ratio of anabolic to androgenic activity of 7:17-dimethyltestosterone, oxymesterone, mestanolone and fluoxymesterone. J Endocrinol. 1963;28:87–92. PubMed.
- Schänzer W, Opfermann G, Donike M. 17-Epimerization of 17 alpha-methyl anabolic steroids in humans: metabolism and synthesis of 17 alpha-hydroxy-17 beta-methyl steroids. Steroids. 1992;57(11):537–550. PubMed.
- Yang S, Lu J, Xu Y, Wang X. New oxymesterone metabolites in human by gas chromatography-tandem mass spectrometry and their application for doping control. Drug Test Anal. 2016;8(7):633–643. PubMed.
- Polet M, Van Gansbeke W, Geldof L, Deventer K, Van Eenoo P. Identification and characterization of novel long-term metabolites of oxymesterone and mesterolone in human urine by application of selected reaction monitoring GC-CI-MS/MS. Drug Test Anal. 2017;9(11-12):1673–1684. PubMed.
- Kratena N, Pfeffer S, Enev VS, Gmeiner G, Gärtner P. Synthesis of human long-term metabolites of dehydrochloromethyltestosterone and oxymesterone. Steroids. 2020;164:108716. PubMed.
- Kennedy MC, Lawrence C. Anabolic steroid abuse and cardiac death. Med J Aust. 1993;158(5):346–348. PubMed.
- Quaini L. On the treatment of some forms of osseous atrophy with 4-hydroxy-17 alpha-methyltestosterone (oranabol) [in Italian]. Minerva Med. 1961;52:392–393. PubMed.
- Quaini L, Valobra M. The protein-anabolic properties of 4-hydroxy-17alpha-methyltestosterone in some forms of osseous atrophy [in Italian]. Minerva Ortop. 1961;12:711–717. PubMed.
- Cala G. Treatment of an operated patient with an anabolic steroid by oral route: 4-hydroxy-17alpha-methyltestosterone [in Italian]. Minerva Chir. 1961;16:1433–1436. PubMed.
- Mirouze J. 4-Hydroxy-17alpha-methyltestosterone, new oral anabolic steroid [in French]. Sem Hop. 1961;37:2567–2571. PubMed.
- Zeneroli ML. Blood cholesterol changes in the course of prolonged treatments with methandrostenolone, oxymesterone and nandrolone [in Italian]. Endocrinol Sci Cost. 1970;31(2):107–114. PubMed.