Metenolone enanthate
Clinical data
Trade namesNibal Injection, Primobolan Depot
Other namesMethenolone enanthate; Metenolone heptanoate; Metenolone 17β-enanthate; NSC-64967; SH-601; SQ-16374; 1-Methyl-4,5α-dihydrotestosterone 17β-heptanoate; 1-Methyl-DHT heptanoate; 1-Methyl-5α-androst-1-en-17β-ol-3-one 17β-heptanoate
Routes of
administration		Intramuscular injection
Drug classAndrogen; Anabolic steroid; Androgen ester
Legal status
Legal status
Pharmacokinetic data
Elimination half-lifeIMTooltip Intramuscular injection: 10.5 days[1]
Identifiers
  • [(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] heptanoate
CAS Number
PubChem CID
ChemSpider
UNII
CompTox Dashboard (EPA)
ECHA InfoCard100.005.584 Edit this at Wikidata
Chemical and physical data
FormulaC27H42O3
Molar mass414.630 g·mol−1
3D model (JSmol)
  • O=C2\C=C(\C)[C@@]3([C@H]1CC[C@@]4([C@@H](OC(=O)CCCCCC)CC[C@H]4[C@@H]1CC[C@H]3C2)C)C
  • InChI=1S/C27H42O3/c1-5-6-7-8-9-25(29)30-24-13-12-22-21-11-10-19-17-20(28)16-18(2)27(19,4)23(21)14-15-26(22,24)3/h16,19,21-24H,5-15,17H2,1-4H3/t19-,21-,22-,23-,24-,26-,27-/m0/s1 checkY
  • Key:TXUICONDJPYNPY-FRXWOFFRSA-N checkY
 ☒NcheckY (what is this?)  (verify)

Metenolone enanthate, or methenolone enanthate, sold under the brand names Primobolan Depot and Nibal Injection, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of anemia due to bone marrow failure.[2][3][4][5][6][7] It is given by injection into muscle.[6] Although it was widely used in the past, the drug has mostly been discontinued and hence is now mostly only available on the black market. [5][6][3] A related drug, metenolone acetate, is taken by mouth.[6]

Side effects of metenolone enanthate include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.[6] 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).[6][8] It has moderate anabolic effects and weak androgenic effects, as well as no estrogenic effects or risk of liver damage.[6][8] Metenolone enanthate is a metenolone ester and a long-lasting prodrug of metenolone in the body.[6]

Metenolone enanthate was introduced for medical use in 1962.[6] In addition to its medical use, metenolone enanthate is used to improve physique and performance.[6] The drug is a controlled substance in many countries and so non-medical use is generally illicit.[6] It remains marketed for medical use only in a few countries, such as Spain and Turkey.[5][6]

Medical uses

Metenolone enanthate has been studied in the treatment of breast cancer.[9][10]

Side effects

See also: Anabolic steroid § Adverse effects

Pharmacology

Pharmacodynamics

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.

As a derivative of DHT, metenolone, the active form of metenolone enanthate, is not aromatized, and so has no propensity for producing estrogenic side effects like gynecomastia.[6] As an AAS, metenolone enanthate is antigonadotropic and can suppress the hypothalamic–pituitary–gonadal axis and produce reversible hypogonadism and infertility.[6][11]

Pharmacokinetics

The biological half-life of metenolone enanthate is reported to be about 10.5 days by intramuscular injection.[1]

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 enanthate, or metenolone 17β-enanthate, is a synthetic androstane steroid and a derivative of DHT.[2][3][6] It is the C17β enanthate (heptanoate) 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.[2][3][6]

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 enanthate was introduced for medical use in 1962 in the United States under the brand name Nibal Depot.[6] It was soon discontinued in the United States and was marketed instead in Europe in the 1960s and 1970s under the brand name Primobolan Depot.[6]

Society and culture

Generic names

Methenolone enanthate is the USANTooltip United States Adopted Name of metenolone enanthate, and methenolone is the BANTooltip British Approved Name of its active form, metenolone.[2][3][4][5] Conversely, metenolone is the INNTooltip International Nonproprietary Name of metenolone.[2][3][4][5]

Brand names

Metenolone enanthate is or has been marketed under the brand names Nibal Injection and Primobolan Depot.[2][3][6][5]

Availability

Metenolone enanthate is marketed in Spain and Turkey.[5][6]

Doping in sports

See also: List of doping in sport cases § Metenolone esters

There are known cases of doping in sports with metenolone enanthate by professional athletes.

References

  1. ^ a b Westreich LM (2011). "Anabolic-Androgenic Steroids". In Ruiz P, Strain EC (eds.). Lowinson and Ruiz's Substance Abuse: A Comprehensive Textbook. Lippincott Williams & Wilkins. pp. 358–. ISBN 978-1-60547-277-5.
  2. ^ a b c d e f Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 784–. ISBN 978-1-4757-2085-3.
  3. ^ a b c d e f g Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. pp. 659–661. ISBN 978-3-88763-075-1.
  4. ^ a b c Morton IK, Hall JM (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. pp. 178–. ISBN 978-94-011-4439-1.
  5. ^ a b c d e f g "List of Androgens and anabolic steroids".
  6. ^ a b c d e f g h i j k l m n o p q r s t William Llewellyn (2011). Anabolics. Molecular Nutrition Llc. pp. 633–. ISBN 978-0-9828280-1-4.
  7. ^ Handelsman DJ (25 February 2015). "Androgen Physiology, Pharmacology, and Abuse". In Jameson JL, De Groot LJ (eds.). Endocrinology: Adult and Pediatric E-Book. Elsevier Health Sciences. pp. 2388–. ISBN 978-0-323-32195-2.
  8. ^ a b Kicman AT (2008). "Pharmacology of anabolic steroids". Br. J. Pharmacol. 154 (3): 502–21. doi:10.1038/bjp.2008.165. PMC 2439524. PMID 18500378.
  9. ^ Kennedy BJ, Yarbro JW (February 1968). "Effect of methenolone enanthate (NSC-64967) in advanced cancer of the breast". Cancer. 21 (2): 197–201. doi:10.1002/1097-0142(196802)21:2<197::AID-CNCR2820210207>3.0.CO;2-R. PMID 4952912.
  10. ^ Notter G (December 1975). "Treatment of disseminated carcinoma of the breast by metenolone enanthate". Acta Radiologica. 14 (6): 545–551. doi:10.3109/02841867509132696. PMID 1224996.
  11. ^ van Breda E, Keizer HA, Kuipers H, Wolffenbuttel BH (Apr 2003). "Androgenic anabolic steroid use and severe hypothalamic-pituitary dysfunction: a case study". Int J Sports Med. 24 (3): 195–196. doi:10.1055/s-2003-39089. PMID 12740738. S2CID 260166539.

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Androgen receptor modulators
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