Drostanolone enanthate, sold outside medicine as “Masteron Enanthate,” is drostanolone with a seven-carbon enanthate (heptanoate) ester attached. Drostanolone itself is an anabolic-androgenic steroid (AAS) made by adding a methyl group to dihydrotestosterone (DHT). The enanthate is the long-ester counterpart of drostanolone propionate, the form that was once a prescription breast cancer drug.
The most important fact is that we found no record of drostanolone enanthate ever being an approved medicine. FDA’s drug database lists only one drostanolone product, Lilly’s Drolban, which contained the propionate ester and is discontinued (Drugs@FDA). No published study has measured the enanthate’s pharmacokinetics, its effects on muscle, or its safety in people. What is known comes from its chemistry, from other enanthate-ester drugs, from laboratory studies and from forensic and anti-doping testing.
This page summarizes what chemistry databases, regulators, laboratory studies and testing data report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | Anabolic-androgenic steroid; 2α-methyl derivative of DHT, as the enanthate (heptanoate) ester |
| Other names | Dromostanolone enanthate; 2α-methyl-3-oxo-5α-androstan-17β-yl heptanoate; CAS 13425-31-5 |
| Approval | No approved product found; the only FDA-listed drostanolone product (Drolban) used the propionate ester and is discontinued |
| Route | Injectable; no approved label exists, so there is no labeled dose |
| Formula and weight | C₂₇H₄₄O₃, 416.6 g/mol |
| Drostanolone content | ≈73% of the ester’s weight (304.5 of 416.6 g/mol) |
| Half-life | No published human data; inferred only by analogy with other enanthate esters |
| Aromatizes to estrogen | Not expected (5α-reduced, DHT-type structure); identified human metabolites are androgens |
| US status | Schedule III anabolic steroid (drostanolone and its esters) |
| WADA status | Prohibited at all times (S1.1 anabolic androgenic steroids) |
What it is
Drostanolone’s chemical name is 17β-hydroxy-2α-methyl-5α-androstan-3-one (21 CFR 1308.13). In plain terms, it is DHT with a methyl group added at carbon 2 of the A-ring. It is not 17α-alkylated, the chemical change that makes oral steroids such as oxandrolone survive the liver.
The enanthate version attaches heptanoic acid to the 17β-hydroxyl group. PubChem lists it under the name dromostanolone enanthate (PubChem). The ester has no hormonal activity of its own. Enzymes cleave it after injection, releasing the same free drostanolone that the propionate releases. The only difference between the two products is how fast that happens, and how much of each milligram is the actual hormone:
| Form | Ester length | Formula | Molecular weight | Drostanolone by weight |
|---|---|---|---|---|
| Drostanolone (free steroid) | None | C₂₀H₃₂O₂ | 304.5 g/mol | 100% |
| Drostanolone propionate | 3 carbons | C₂₃H₃₆O₃ | 360.5 g/mol | ≈84% |
| Drostanolone enanthate | 7 carbons | C₂₇H₄₄O₃ | 416.6 g/mol | ≈73% |
Formulas and weights from PubChem (drostanolone; propionate; enanthate).
So 100 mg of the enanthate contains about 73 mg of drostanolone, versus about 84 mg in 100 mg of the propionate.
Because the active hormone is identical, the receptor pharmacology, metabolism, the old breast cancer trials, and the debunked “anti-estrogen” and anabolic:androgenic ratio claims are covered on the drostanolone propionate page. A related but different drug is mesterolone (Proviron), which carries its methyl group at carbon 1 instead of carbon 2 (de Boer et al., J Steroid Biochem Mol Biol 1992).
About the “anticancer steroid” label. A laboratory paper on the enanthate calls it an “anti-cancer steroid” in its title (Choudhary et al., Front Pharmacol 2017). The same authors note in their introduction that it was the propionate ester that was used to treat breast cancer. We found no clinical study of the enanthate in cancer or any other disease.
Pharmacokinetics
No human pharmacokinetic study of drostanolone enanthate has been published. Its absorption rate, peak timing and half-life in people are unknown, and any specific half-life quoted for it is an extrapolation from other drugs.
What the enanthate ester does
The general behavior of long esters is well documented for testosterone and nandrolone, and is the basis for the assumption that drostanolone enanthate acts longer than the propionate:
- Testosterone enanthate label. Esterifying the 17β-hydroxyl group “increases the duration of action,” and the ester is hydrolyzed to free hormone in the body. Esters in oil injected into muscle are absorbed slowly from the oil, so testosterone enanthate can be given every 2–4 weeks (testosterone enanthate label).
- Duration after one injection. In hypogonadal men, a single 200 mg intramuscular dose of testosterone enanthate kept testosterone in the normal range through day 11, and a 100 mg dose through day 7 (Sokol et al., Fertil Steril 1982).
- Ester length changes the curve. In a randomized study of 23 healthy men given 100 mg nandrolone, the shorter phenylpropionate ester produced higher and earlier peaks than the longer decanoate ester. Injection site and injection volume also changed blood levels (Minto et al., J Pharmacol Exp Ther 1997).
These studies used testosterone and nandrolone, not drostanolone. They support the direction of the effect (slower, longer release than the propionate) but not any specific number for drostanolone enanthate.
Metabolism and detection
Once the ester is removed, the body handles drostanolone the same way whatever ester it came from. Its main urinary metabolite is 2α-methyl-androsterone, with the parent drug and 3α,17β-diol metabolites also found, all conjugated to glucuronic acid (de Boer et al., 1992).
| Study | Finding |
|---|---|
| One male volunteer, intramuscular injection (Liu et al., Steroids 2016) | 11 urinary metabolites; two new markers detectable for up to 24 days |
| Two excretion studies (Albertsdóttir et al., Drug Test Anal 2020) | Main glucuronide metabolite detectable for up to 29 days; a sulfate metabolite for up to 24 days |
| Post-mortem hair testing (Gheddar et al., J Anal Toxicol 2023) | Intact drostanolone enanthate found in head hair (26–5 pg/mg across segments), alongside drostanolone and drostanolone propionate |
The two urine abstracts do not state which drostanolone ester was given. These are detection windows for sensitive anti-doping tests, not elimination half-lives. Finding a trace metabolite weeks later does not mean the drug is still active.
Medical use and regulatory status
Drostanolone enanthate has no approved medical use. Drostanolone’s medical history belongs to the propionate ester, which was used to treat breast cancer (Choudhary et al., 2017). The US propionate product, Drolban (50 mg/mL), is listed as discontinued (Drugs@FDA). That history and the trials behind it are covered on the propionate page.
What the research shows
In people
No clinical trial, case series or pharmacology study has tested drostanolone enanthate in people for any outcome. No study has measured muscle mass, strength, body composition or athletic performance with drostanolone in any ester form. Claims that it “hardens” the physique, or that the enanthate gives a steadier effect than the propionate, are not based on published data.
In the laboratory
The only published studies that used the enanthate itself are chemistry papers from one research group. They used fungi to convert the drug into new metabolites and then tested those compounds on cells:
- Fungal biotransformation. Two fungi converted drostanolone enanthate into eight metabolites, five of them new (Choudhary et al., 2017). A second study with two other microbial cultures produced seven new metabolites (Hussain et al., RSC Adv 2020). These are microbial products, not a description of human metabolism.
- Cancer cell lines. In cell culture, the parent drug’s IC₅₀ (the concentration that halves cell growth) was 54.7 μM against cervical cancer (HeLa) cells, 96.2 μM against prostate cancer (PC-3) cells and 3.1 μM against colon cancer (HCT116) cells. Several of the fungal metabolites were more active (Choudhary et al., 2017).
These are results in cell culture. They do not show that the drug has any anticancer effect in people.
Side effects and risks
Because drostanolone enanthate has never been studied in people, its side-effect rates are unknown. The risks below are those documented for anabolic steroids as a class.
Effects shared with other anabolic steroids
A major pharmacology review lists these class effects (Kicman, Br J Pharmacol 2008):
- Hormones and fertility: suppression of the body’s own testosterone production and testicular shrinkage. Recovery of fertility can take months up to about a year after stopping.
- Heart and blood: higher LDL cholesterol, lower HDL cholesterol, a higher hematocrit (the share of blood made up of red cells), and a higher risk of thrombotic events such as heart attack and stroke. Heart damage, including left ventricular hypertrophy, has been linked to long-term use.
- Skin: cystic acne, which can be severe on the chest, back and face.
- Breast: gynecomastia in men. The review notes that it can occur even with steroids that resist conversion to estrogen.
- Injection: serious infection associated with injected drugs.
The same review ties liver toxicity mainly to 17α-alkylated oral steroids. Drostanolone enanthate is not 17α-alkylated, but its liver safety has not been studied.
Why a long ester matters for side effects
With a long ester, blood levels fall slowly after the last injection. In the nandrolone study, the longer decanoate ester (given as a 1 mL gluteal injection) produced the most sustained suppression of the men’s own testosterone, while the shorter phenylpropionate ester produced the briefest (Minto et al., 1997). By analogy, unwanted effects of an enanthate ester would be expected to take longer to wear off than those of a propionate. This has not been measured for drostanolone.
Virilization in women
In women, anabolic steroids can cause deepening of the voice and clitoral growth, and the review describes both as irreversible (Kicman, 2008). A long-acting ester leaves no way to stop exposure quickly once such changes begin.
Deaths and case reports
In one forensic case, a 29-year-old man who trained regularly and used anabolic drugs was found dead at home after an unremarkable autopsy. Hair and nail testing found more than ten anabolic steroids and esters, including drostanolone enanthate, and the experts attributed the death to massive repetitive steroid use over the previous months (Gheddar et al., 2023). A case like this cannot show which drug, if any, caused death.
Quality and contamination
Every drostanolone enanthate product comes from outside the regulated drug supply, so dose, sterility and identity are not controlled by any regulator. Testing of seized products shows what that means in practice:
- Denmark: of 764 performance and image-enhancing products seized by police from December 2019 to December 2020, 60% contained anabolic steroids. In 25–34% of products, the active ingredient was missing or different from the label, although only 7–10% contained no active ingredient or one from a different drug class (Heinsvig et al., Drug Test Anal 2023).
- Brazil: of 40 seized injectable and capsule steroid products, including drostanolone propionate products, 8 did not contain the labeled active ingredient. Others were under-dosed or adulterated, and 4 contained sildenafil (Ribeiro et al., Steroids 2018).
Legal status and use outside medicine
In the US, drostanolone is listed by name as a Schedule III anabolic steroid, and the listing covers its salts, esters and ethers, which includes the enanthate (21 CFR 1308.13).
Drostanolone is named in section S1.1 (anabolic androgenic steroids) of the World Anti-Doping Agency 2026 Prohibited List. It is prohibited at all times, in and out of competition, and is a non-Specified Substance (WADA 2026 Prohibited List).
Drostanolone is among the most commonly detected steroids in testing:
- Anti-doping researchers describe it as one of the most frequently detected AAS in doping control (Liu et al., 2016).
- In 21,172 samples tested at a Swedish drug-abuse laboratory from 2014 to 2023, the most common AAS detected were consistently testosterone, nandrolone and drostanolone (Bohlin et al., Drug Test Anal 2025).
Routine urine tests detect drostanolone metabolites, so they generally cannot tell which ester was used.
Key takeaways
- Same hormone, longer ester. The enanthate releases the same drostanolone as the propionate. It is about 73% drostanolone by weight, versus about 84% for the propionate.
- Never an approved medicine. We found no approved product; the only FDA-listed drostanolone drug used the propionate ester and is discontinued.
- No human data on kinetics or effects. Its half-life in people has never been measured, and no study has tested it for muscle, strength or any medical use.
- “Longer-acting” is an inference. Studies of testosterone and nandrolone esters show that longer esters release more slowly and suppress natural testosterone for longer, but the numbers have not been measured for drostanolone.
- Class risks apply, for longer. Expect suppressed natural testosterone, unfavorable lipid changes and, in women, virilization that may be permanent, with effects that wear off slowly after the last dose.
- Controlled, banned and unregulated. It is Schedule III in the US and prohibited at all times by WADA, and every product on the market is unregulated.
Sources
- Food and Drug Administration. Drugs@FDA: NDA 012936, Drolban (dromostanolone propionate) injection, 50 mg/mL, Lilly. Drugs@FDA.
- National Center for Biotechnology Information. Dromostanolone enanthate, PubChem CID 13014314; dromostanolone, CID 6011; dromostanolone propionate, CID 224004. PubChem (enanthate); PubChem (drostanolone); PubChem (propionate).
- Drug Enforcement Administration. 21 CFR 1308.13(f), Schedule III anabolic steroids. Electronic Code of Federal Regulations. eCFR.
- World Anti-Doping Agency. The 2026 Prohibited List, in force January 1, 2026. WADA 2026 Prohibited List.
- Hikma Pharmaceuticals USA. Testosterone Enanthate Injection, USP, prescribing information. DailyMed.
- Sokol RZ, Palacios A, Campfield LA, Saul C, Swerdloff RS. Comparison of the kinetics of injectable testosterone in eugonadal and hypogonadal men. Fertil Steril. 1982;37(3):425–430. PubMed.
- Minto CF, Howe C, Wishart S, Conway AJ, Handelsman DJ. Pharmacokinetics and pharmacodynamics of nandrolone esters in oil vehicle: effects of ester, injection site and injection volume. J Pharmacol Exp Ther. 1997;281(1):93–102. PubMed.
- de Boer D, de Jong EG, Maes RA, van Rossum JM. The methyl-5 alpha-dihydrotestosterones mesterolone and drostanolone; gas chromatographic/mass spectrometric characterization of the urinary metabolites. J Steroid Biochem Mol Biol. 1992;42(3-4):411–419. PubMed.
- Liu Y, Lu J, Yang S, Zhang Q, Xu Y. New drostanolone metabolites in human urine by liquid chromatography time-of-flight tandem mass spectrometry and their application for doping control. Steroids. 2016;108:61–67. PubMed.
- Albertsdóttir AD, Van Gansbeke W, Coppieters G, et al. Searching for new long-term urinary metabolites of metenolone and drostanolone using gas chromatography-mass spectrometry with a focus on non-hydrolysed sulfates. Drug Test Anal. 2020;12(8):1041–1053. PubMed.
- Gheddar L, Blanchot A, Ameline A, Arbouche N, Raul JS, Kintz P. The power of keratinous matrices (head hair, body hair and nail clippings) analysis in a case of death involving anabolic agents. J Anal Toxicol. 2023;46(9):e307–e313. PubMed.
- Choudhary MI, Siddiqui M, Atia-Tul-Wahab, et al. Bio-catalytic structural transformation of anti-cancer steroid, drostanolone enanthate with Cephalosporium aphidicola and Fusarium lini, and cytotoxic potential evaluation of its metabolites against certain cancer cell lines. Front Pharmacol. 2017;8:900. PubMed; PMC.
- Hussain Z, Atia-Tul-Wahab, Hussain N, et al. Seven new metabolites of drostanolone heptanoate by using Beauveria bassiana, and Macrophomina phaseolina cell suspension cultures. RSC Adv. 2020;10(1):451–460. PubMed.
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol. 2008;154(3):502–521. PubMed; PMC.
- Heinsvig PJ, Christiansen AV, Ayoubi D, Heisel LS, Lindholst C. Do you get what you see? The illicit doping market in Denmark—an analysis of performance and image enhancing drugs seized by the police over a 1-year period. Drug Test Anal. 2023;15(6):668–677. PubMed.
- Ribeiro MVM, Boralle N, Felippe LG, Pezza HR, Pezza L. 1H NMR determination of adulteration of anabolic steroids in seized drugs. Steroids. 2018;138:47–56. PubMed.
- Bohlin KP, Villén T, Hopcraft O, Pohanka A, Ekström L. 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.