Metenolone acetate

Metenolone acetate, or methenolone acetate, sold under the brand names Primobolan and Nibal, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of anemia due to bone marrow failure.^{[1][2][3][4][5][6]} It is taken by mouth.^[5] Although it was widely used in the past, the drug has mostly been discontinued and hence is now mostly no longer available.^[4][5][2] A related drug, metenolone enanthate, is given by injection into muscle.^[5]

Metenolone acetate

Clinical data
Trade names	Primobolan, Primobolan S, Primonabol, Nibal
Other names	Methenolone acetate; NSC-74226; SH-567; SQ-16496; Methenolone 17β-acetate; 1-Methyl-δ1-4,5α-dihydrotestosterone 17β-acetate; 1-Methyl-δ1-DHT acetate; 1-Methylandrost-1,4-dien-17β-ol-3-one 17β-acetate
Routes of administration	By mouth
Drug class	Androgen; Anabolic steroid; Androgen ester
Identifiers
IUPAC name [(5S,8R,9S,10S,13S,14S,17S)-1,10,13-Trimethyl-3-oxo-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl] acetate
CAS Number	434-05-9
PubChem CID	252372
ChemSpider	221129
UNII	W75590VPKQ
CompTox Dashboard (EPA)	DTXSID40963004
ECHA InfoCard	100.006.453
Chemical and physical data
Formula	C22H32O3
Molar mass	344.495 g·mol−1
3D model (JSmol)	Interactive image
SMILES CC1=CC(=O)C[C@H]2[C@]1([C@H]3CC[C@]4([C@H]([C@@H]3CC2)CC[C@@H]4OC(=O)C)C)C
InChI InChI=1S/C22H32O3/c1-13-11-16(24)12-15-5-6-17-18-7-8-20(25-14(2)23)21(18,3)10-9-19(17)22(13,15)4/h11,15,17-20H,5-10,12H2,1-4H3/t15-,17-,18-,19-,20-,21-,22-/m0/s1 Key:PGAUJQOPTMSERF-QWQRBHLCSA-N

Side effects of metenolone acetate include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.^[5] The drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).^[5][7] It has moderate anabolic effects and weak androgenic effects, as well as no estrogenic effects or risk of liver damage.^[5][7] Metenolone enanthate is a metenolone ester and a prodrug of metenolone in the body.^[5]

Metenolone acetate was introduced for medical use in 1961.^[8][5] In addition to its medical use, metenolone acetate is used to improve physique and performance.^[5] The drug is a controlled substance in many countries and so non-medical use is generally illicit.^[5] It remains marketed for medical use only in a few countries, such as Japan and Moldova.^[4][5]

Side effects

See also: Anabolic steroid § Adverse effects

Pharmacology

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Androgenic vs. anabolic activity ratio
of androgens/anabolic steroids

Medication	Ratioa
Testosterone	~1:1
Androstanolone (DHT)	~1:1
Methyltestosterone	~1:1
Methandriol	~1:1
Fluoxymesterone	1:1–1:15
Metandienone	1:1–1:8
Drostanolone	1:3–1:4
Metenolone	1:2–1:30
Oxymetholone	1:2–1:9
Oxandrolone	1:3–1:13
Stanozolol	1:1–1:30
Nandrolone	1:3–1:16
Ethylestrenol	1:2–1:19
Norethandrolone	1:1–1:20
Notes: In rodents. Footnotes: a = Ratio of androgenic to anabolic activity. Sources: See template.

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Parenteral durations of androgens/anabolic steroids

Medication	Form	Major brand names	Duration
Testosterone	Aqueous suspension	Andronaq, Sterotate, Virosterone	2–3 days
Testosterone propionate	Oil solution	Androteston, Perandren, Testoviron	3–4 days
Testosterone phenylpropionate	Oil solution	Testolent	8 days
Testosterone isobutyrate	Aqueous suspension	Agovirin Depot, Perandren M	14 days
Mixed testosterone estersa	Oil solution	Triolandren	10–20 days
Mixed testosterone estersb	Oil solution	Testosid Depot	14–20 days
Testosterone enanthate	Oil solution	Delatestryl	14–28 days
Testosterone cypionate	Oil solution	Depovirin	14–28 days
Mixed testosterone estersc	Oil solution	Sustanon 250	28 days
Testosterone undecanoate	Oil solution	Aveed, Nebido	100 days
Testosterone buciclated	Aqueous suspension	20 Aet-1, CDB-1781e	90–120 days
Nandrolone phenylpropionate	Oil solution	Durabolin	10 days
Nandrolone decanoate	Oil solution	Deca Durabolin	21–28 days
Methandriol	Aqueous suspension	Notandron, Protandren	8 days
Methandriol bisenanthoyl acetate	Oil solution	Notandron Depot	16 days
Metenolone acetate	Oil solution	Primobolan	3 days
Metenolone enanthate	Oil solution	Primobolan Depot	14 days
Note: All are via i.m. injection. Footnotes: a = TP, TV, and TUe. b = TP and TKL. c = TP, TPP, TiCa, and TD. d = Studied but never marketed. e = Developmental code names. Sources: See template.

Chemistry

See also: List of androgens/anabolic steroids and List of androgen esters

Metenolone acetate, or metenolone 17β-acetate, is a synthetic androstane steroid and a derivative of DHT.^[1][2][5] It is the C17β acetate ester of metenolone, which itself is 1-methyl-δ¹-4,5α-dihydrotestosterone (1-methyl-δ¹-DHT) or 1-methyl-5α-androst-1-en-17β-ol-3-one.^[1][2][5]

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Structural properties of major anabolic steroid esters

Anabolic steroid	Structure	Ester				Relative mol. weight	Relative AAS contentb	Durationc
		Position	Moiety	Type	Lengtha
Boldenone undecylenate		C17β	Undecylenic acid	Straight-chain fatty acid	11	1.58	0.63	Long
Drostanolone propionate		C17β	Propanoic acid	Straight-chain fatty acid	3	1.18	0.84	Short
Metenolone acetate		C17β	Ethanoic acid	Straight-chain fatty acid	2	1.14	0.88	Short
Metenolone enanthate		C17β	Heptanoic acid	Straight-chain fatty acid	7	1.37	0.73	Long
Nandrolone decanoate		C17β	Decanoic acid	Straight-chain fatty acid	10	1.56	0.64	Long
Nandrolone phenylpropionate		C17β	Phenylpropanoic acid	Aromatic fatty acid	– (~6–7)	1.48	0.67	Long
Trenbolone acetate		C17β	Ethanoic acid	Straight-chain fatty acid	2	1.16	0.87	Short
Trenbolone enanthated		C17β	Heptanoic acid	Straight-chain fatty acid	7	1.41	0.71	Long
Footnotes: a = Length of ester in carbon atoms for straight-chain fatty acids or approximate length of ester in carbon atoms for aromatic fatty acids. b = Relative androgen/anabolic steroid content by weight (i.e., relative androgenic/anabolic potency). c = Duration by intramuscular or subcutaneous injection in oil solution. d = Never marketed. Sources: See individual articles.

History

Metenolone acetate was first introduced for medical use in West Germany in 1961 under the brand name Primobolan and in the United States in 1962.^[8][5]

Society and culture

Generic names

Metenolone acetate is the generic name of the drug and its INNTooltip International Nonproprietary Name, while methenolone acetate is its USANTooltip United States Adopted Name and BANMTooltip British Approved Name.^{[1][2][3][4][5]}

Brand names

Metenolone acetate is or has been marketed under a number of brand names including Primobolan, Primobolan S, Primonabol, and Nibal.^{[1][2][3][4][5]}

Availability

Metenolone acetate is marketed in Japan and Moldova.^[4][5]