Stenbolone acetate is a synthetic anabolic-androgenic steroid (AAS) built on the dihydrotestosterone (DHT) skeleton. It is the 17β-acetate ester of stenbolone, a DHT derivative with a double bond between carbons 1 and 2 and a methyl group at carbon 2. The US Adopted Names (USAN) council gave it its official name, and the National Library of Medicine lists Anatrofin as a synonym.
The most important fact about this compound is how little is known about it in people. We found no controlled clinical trial of stenbolone acetate for any outcome. The human literature consists of a 1969 Mexican report on the ovary and two 1990s drug-testing studies that each gave a single dose to volunteers to map its urinary metabolites. It is not an FDA-approved drug, it is named as a Schedule III anabolic steroid in US law, and it is banned in sport at all times.
This page summarizes what chemistry databases, the few published studies and regulators report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | Anabolic-androgenic steroid; DHT derivative (2-methyl-Δ1-DHT), 17β-acetate ester |
| Names | Stenbolone acetate (USAN); stenbolone is the INN for the parent steroid; Anatrofin listed as a synonym |
| Approval | No FDA-approved product; no current labeled use found |
| Route studied in humans | Oral, single 50 mg dose, in metabolism studies only |
| Formula and weight | C₂₂H₃₂O₃, 344.5 g/mol (stenbolone itself: C₂₀H₃₀O₂, 302.5 g/mol) |
| Steroid content | ≈88% of the ester’s weight is stenbolone |
| Half-life | Not published in any source we could find |
| US status | Schedule III (stenbolone and its esters, 21 CFR 1308.13) |
| WADA status | Prohibited at all times (S1.1 anabolic androgenic steroids) |
What it is
Stenbolone’s chemical name is 17β-hydroxy-2-methyl-5α-androst-1-en-3-one (21 CFR 1308.13). The acetate ester, 17β-acetoxy-2-methyl-5α-androst-1-en-3-one, has the formula C₂₂H₃₂O₃ and a molecular weight of 344.5 g/mol (PubChem CID 10315500). The free steroid weighs 302.5 g/mol (PubChem CID 234454), so about 88% of the ester’s weight is stenbolone.
The FDA’s substance registry lists “stenbolone acetate” as the USAN name and “stenbolone” as the International Nonproprietary Name (INN) of the parent steroid (FDA GSRS: stenbolone acetate; FDA GSRS: stenbolone). The NLM’s MeSH vocabulary lists “Anatrofin” as an alternate name for the acetate (MeSH C069086). We could not find a primary source documenting who marketed it, in which countries or when, so we do not repeat those claims here.
Stenbolone belongs to a small family of Δ1 (“1-ene”) DHT derivatives. They differ only in where small methyl groups sit:
| Steroid | Chemical name | Difference from 1-testosterone |
|---|---|---|
| Δ1-DHT (“1-testosterone”) | 17β-hydroxy-5α-androst-1-en-3-one | Reference structure |
| Methenolone (Primobolan) | 1-methyl-17β-hydroxy-5α-androst-1-en-3-one | Methyl at carbon 1 |
| Stenbolone | 17β-hydroxy-2-methyl-5α-androst-1-en-3-one | Methyl at carbon 2 |
| Methylstenbolone | 2,17α-dimethyl-17β-hydroxy-5α-androst-1-en-3-one | Methyl at carbon 2 plus a 17α-methyl group |
Names for the first three from 21 CFR 1308.13; methylstenbolone from Cavalcanti et al., Steroids 2013.
The acetate group itself has no hormonal activity. As with other steroid esters, it is expected to be cleaved in the body to release free stenbolone. Stenbolone acetate is not 17α-alkylated, which separates it from its oral cousin methylstenbolone, a “designer” steroid that has been linked to cholestatic liver injury in case reports (Agbenyefia et al., 2014). Its closest well-studied relative is methenolone, available on this site as Primobolan acetate and Primobolan enanthate.
Because stenbolone is already a 5α-reduced DHT derivative, it is not expected to be converted to estrogen by aromatase. No published study has measured this directly.
About potency claims. Online sources describe stenbolone as a “mild,” “dry” or highly anabolic steroid and quote anabolic:androgenic ratios. We could not trace any of these figures to a published assay in animals or humans, so we do not repeat them. No controlled data on its muscle, strength or body-composition effects exist.
How it behaves in the body
The only human pharmacology data come from a Canadian drug-testing laboratory. In 1991, Goudreault and Massé gave a single 50 mg oral dose of stenbolone acetate to one male volunteer and collected urine (Goudreault & Massé, J Steroid Biochem Mol Biol 1991):
| Finding | Result |
|---|---|
| Volunteers | 1 man, single 50 mg oral dose |
| Metabolites identified in urine | 9 |
| Unchanged stenbolone detectable | More than 120 h after the dose |
| Unchanged stenbolone recovered | 6.6% of the dose (cumulative) |
| Main conjugate | Glucuronides; only 16-hydroxylated metabolites appeared as sulfates |
| Unconjugated (free) metabolites | None detected |
The main metabolic routes were oxidation of the 17β-hydroxyl group, reduction of the A-ring double bond and 3-keto group, and hydroxylation at carbon 16. The authors noted that these routes closely match those of methenolone acetate.
A follow-up from the same group gave single 50 mg doses of stenbolone, methenolone and mesterolone to human subjects. It found an additional 18-hydroxylated metabolite of stenbolone in urine (Massé & Goudreault, J Steroid Biochem Mol Biol 1992).
These studies were designed to help anti-doping labs detect the drug. They did not measure blood levels, so they give no half-life, peak time or bioavailability. Detection in urine for over 120 hours after one dose is a detection window, not a half-life. We found no published pharmacokinetic data at all for the acetate given by injection.
Medical use and regulatory status
We found no approved medical use for stenbolone acetate:
- United States. No stenbolone product appears in FDA’s Drugs@FDA or National Drug Code databases (openFDA). Stenbolone is named in the Schedule III list of anabolic steroids, which covers “its salts, esters and ethers,” so the acetate is a Schedule III controlled substance (21 CFR 1308.13).
- Sport. Stenbolone is named under S1.1 anabolic androgenic steroids on the WADA list, which also covers their esters. It is prohibited in and out of competition and is a non-specified substance (WADA 2026 Prohibited List).
What the research shows
There are no controlled human trials of stenbolone acetate for muscle mass, strength, body composition, wasting or any other outcome. The human literature we could find is:
- A 1969 Mexican report titled “Effects of a new anabolic (stenbolone acetate) on the physiology of the normal ovary” (Villanueva Gasca et al., Ginecol Obstet Mex 1969). It is in Spanish, has no indexed abstract, and we could not review its methods or results.
- The two single-dose metabolism studies described above, which were built for doping detection, not to test effects.
Any claim about how much muscle stenbolone builds, how it compares with other steroids, or what dose is “effective” has no published human data behind it.
Side effects and risks
No study has systematically recorded side effects of stenbolone acetate in people. What can be said is limited to what is known for anabolic-androgenic steroids as a class, and to what the lack of data means.
Class effects of anabolic steroids
An Endocrine Society scientific statement links non-medical use of performance-enhancing drugs, mainly AAS, with a higher risk of death and with cardiovascular, psychiatric, metabolic, endocrine, liver, kidney and musculoskeletal disorders (Pope et al., Endocr Rev 2014). The statement also notes that users often take very high doses and combine several drugs, which makes individual compounds hard to study.
Hormonal suppression and fertility
Androgens shut down the body’s own testosterone and sperm production by suppressing the pituitary signals LH and FSH. A review of anabolic steroid-induced hypogonadism (low testosterone after stopping steroids) found it can cause symptoms that may need medical treatment, and that the risk likely depends on the dose, duration and type of steroid (Rahnema et al., Fertil Steril 2014). No study has measured how strongly stenbolone itself suppresses these hormones.
Product identity and quality
Because there is no approved product, anything sold as stenbolone acetate comes from outside the regulated drug supply. Its identity, dose and sterility cannot be assumed. Use does turn up in testing. When a Swedish drugs-of-abuse laboratory reanalyzed 310 urine samples from 2022–2023 with a broader steroid panel, 86 contained AAS. Stenbolone was found in 1 of them, compared with 57 for testosterone and 3 for methylstenbolone (Bohlin et al., Drug Test Anal 2025).
Key takeaways
- A DHT derivative with almost no human data. Stenbolone is 2-methyl-Δ1-DHT, a close structural relative of methenolone; the acetate is its 17β-ester and is about 88% stenbolone by weight.
- No clinical trials. Published human data are limited to a 1969 report we could not review and two single-dose urine metabolism studies.
- No known half-life. After one 50 mg oral dose, unchanged stenbolone was detectable in urine for more than 120 hours, but no study has measured blood levels.
- Not 17α-alkylated. It should not be confused with methylstenbolone, the oral 17α-methyl designer steroid linked to liver injury in case reports.
- Controlled and banned. It has no FDA approval, is Schedule III in the US as an ester of stenbolone, and is prohibited at all times under WADA rules.
- Unverified folklore. Claims about its potency, “dryness” or anabolic:androgenic ratio have no traceable primary source.
Sources
- National Center for Biotechnology Information. Stenbolone acetate, PubChem CID 10315500. PubChem.
- National Center for Biotechnology Information. Stenbolone, PubChem CID 234454. PubChem.
- US Food and Drug Administration. Global Substance Registration System: stenbolone acetate (UNII 36HF75V9XI) and stenbolone (UNII 3Q6FKA848S). GSRS; GSRS.
- National Library of Medicine. Medical Subject Headings supplementary concept: stenbolone acetate (C069086). MeSH.
- Goudreault D, Massé R. Studies on anabolic steroids–6. Identification of urinary metabolites of stenbolone acetate (17 beta-acetoxy-2-methyl-5 alpha-androst-1-en-3-one) in human by gas chromatography/mass spectrometry. J Steroid Biochem Mol Biol. 1991;38(5):639–655. PubMed.
- Massé R, Goudreault D. Studies on anabolic steroids–11. 18-hydroxylated metabolites of mesterolone, methenolone and stenbolone: new steroids isolated from human urine. J Steroid Biochem Mol Biol. 1992;42(3-4):399–410. PubMed.
- Villanueva Gasca A, Bravo Gutiérrez R, Conde BI, et al. Effects of a new anabolic (stenbolone acetate) on the physiology of the normal ovary [in Spanish]. Ginecol Obstet Mex. 1969;25(149):301–310. PubMed.
- Cavalcanti GA, Leal FD, Garrido BC, et al. Detection of designer steroid methylstenbolone in “nutritional supplement” using gas chromatography and tandem mass spectrometry: elucidation of its urinary metabolites. Steroids. 2013;78(2):228–233. PubMed.
- Agbenyefia P, Arnold CA, Kirkpatrick R 3rd. Cholestatic jaundice with the use of methylstenbolone and dymethazine, designer steroids found in Super DMZ Rx 2.0 “nutritional supplement”: a case report. J Investig Med High Impact Case Rep. 2014;2(2):2324709614532800. PubMed.
- US Food and Drug Administration. openFDA Drugs@FDA query for stenbolone (no matching products). openFDA.
- Code of Federal Regulations. 21 CFR 1308.13, Schedule III, paragraph (f) anabolic steroids. eCFR.
- World Anti-Doping Agency. The 2026 Prohibited List, International Standard. In effect January 1, 2026. WADA.
- Pope HG Jr, Wood RI, Rogol A, et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev. 2014;35(3):341–375. PubMed.
- Rahnema CD, Lipshultz LI, Crosnoe LE, et al. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertil Steril. 2014;101(5):1271–1279. PubMed.
- Bohlin KP, Villén T, Hopcraft O, et al. Prevalence of AAS-positive samples at Drug Abuse Laboratory Sweden between 2014 and 2023 and sub-study of dual use of AAS and narcotics. Drug Test Anal. 2025;17(12):2421–2428. PubMed.