Chemistry:Metenolone

Short description: Chemical compound

Metenolone

Clinical data
Trade names	Primobolan, Nibal (as metenolone acetate); Primobolan Depot, Nibal Injection (as metenolone enanthate)
Other names	Methenolone; Methylandrostenolone; 1-Methyl-δ1-4,5α-dihydrotestosterone; 1-Methyl-δ1-DHT; 1-Methyl-5α-androst-1-en-17β-ol-3-one
AHFS/Drugs.com	International Drug Names
Routes of administration	By mouth (as metenolone acetate), intramuscular injection (as metenolone enanthate)
Drug class	Androgen; Anabolic steroid
ATC code	A14AA04 (WHO)
Legal status
Legal status	BR: Class C5 (Anabolic steroids) CA: Schedule IV US: Schedule III
Identifiers
IUPAC name (5S,8R,9S,10S,13S,14S,17S)-17-hydroxy-1,10,13-trimethyl-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one
CAS Number	153-00-4 Y
PubChem CID	3037705
ChemSpider	2301378 Y
UNII	9062ZT8Q5C
Chemical and physical data
Formula	C20H30O2
Molar mass	302.458 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C2\C=C(\C)[C@@]3([C@H]1CC[C@@]4([C@@H](O)CC[C@H]4[C@@H]1CC[C@H]3C2)C)C
InChI InChI=1S/C20H30O2/c1-12-10-14(21)11-13-4-5-15-16-6-7-18(22)19(16,2)9-8-17(15)20(12,13)3/h10,13,15-18,22H,4-9,11H2,1-3H3/t13-,15-,16-,17-,18-,19-,20-/m0/s1 Y Key:ANJQEDFWRSLVBR-VHUDCFPWSA-N Y

Metenolone, or methenolone, is an androgen and anabolic steroid (AAS) which is used in the form of esters such as metenolone acetate (brand name Primobolan, Nibal) and metenolone enanthate (brand name Primobolan Depot, Nibal Injection). Metenolone esters are used mainly in the treatment of anemia due to bone marrow failure. Metenolone acetate is taken by mouth, while metenolone enanthate is given by injection into muscle.

Side effects of metenolone esters include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire. Metenolone esters are synthetic androgens and anabolic steroids and hence are agonists of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT). They have moderate anabolic effects and weak androgenic effects, as well as no estrogenic effects or risk of liver damage. Metenolone esters are androgen esters and prodrugs of metenolone in the body.

Metenolone esters were introduced for medical use in the early 1960s. In addition to their medical use, metenolone esters are used to improve physique and performance. The drugs are controlled substances in many countries and so non-medical use is generally illicit. They have mostly been discontinued for medical use and have limited availability.

Medical uses

Metenolone, as its esters, is used almost exclusively in the treatment of anemia due to bone marrow failure. It has also been used to treat wasting syndromes due to major surgery, infection, long-term corticosteroid therapy, malnutrition, or other causes. It has also been used to treat osteoporosis and sarcopenia, to inhibit the natural loss of muscle mass with aging, and to promote weight gain in underweight premature infants and children.

Side effects

Side effects of metenolone and its esters include virilization among others.

Pharmacology

Pharmacodynamics

Androgenic vs. anabolic activity
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.

Due to its double bond between the C1 and C2 positions, metenolone is resistant to metabolism by 3α-hydroxysteroid dehydrogenase (3α-HSD). As such, unlike DHT and the closely related DHT derivatives mestanolone (17α-methyl-DHT) and mesterolone (1α-methyl-DHT), metenolone has considerable anabolic effects.

Pharmacokinetics

Metenolone has very low affinity for human serum sex hormone-binding globulin (SHBG), about 16% of that of testosterone and 3% of that of DHT.

Chemistry

Metenolone, also known as 1-methyl-4,5α-dihydro-δ¹-testosterone (1-methyl-δ¹-DHT) or as 1-methyl-5α-androst-1-en-17β-ol-3-one, is a synthetic androstane steroid and derivative of dihydrotestosterone (DHT). A closely related AAS is mesterolone (1α-methyl-DHT).

Society and culture

Generic names

Metenolone is the generic name of the drug and its INN, while methenolone is its BAN. It has also been referred to as methylandrostenolone. This synonym should not be confused with methandrostenolone, which is another name for a different AAS known as metandienone.

Doping in sports

Metenolone and its esters are banned from use in sports governed by the World Anti-Doping Agency. The NBA and NBPA also banned the use of metenolone and its esters under the Anti-Drug Program. There are known cases of doping in sports with metenolone esters by professional athletes.

External links

• Primobolan (methenolone acetate) - William Llewellyn's Anabolic.org
• Primobolan Depot (methenolone enanthate) - William Llewellyn's Anabolic.org

{{Navbox

| name = Androgens and antiandrogens
| title = Androgens and antiandrogens
| state = collapsed
| listclass = hlist
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| group1 = Androgens
(incl. AAS)

| list1 =

AR agonists

Testosterone derivatives: Androstenediol dipropionate Boldenone undecylenate Clostebol Clostebol acetate Clostebol caproate Clostebol propionate Cloxotestosterone acetate Prasterone (dehydroepiandrosterone, DHEA) Prasterone enanthate (DHEA enanthate) Prasterone sulfate (DHEA sulfate) Quinbolone Testosterone# Testosterone esters (e.g., testosterone cypionate, testosterone enanthate]], testosterone propionate]], testosterone undecanoate]], testosterone ester mixture]]s (Deposterona, Omnadren, Sustanon, Testoviron Depot)) Dihydrotestosterone derivatives: Androstanolone (stanolone, dihydrotestosterone, DHT) Androstanolone esters Bolazine capronate Drostanolone propionate (dromostanolone propionate) Epitiostanol Mepitiostane Mesterolone Metenolone acetate (methenolone acetate) Metenolone enanthate (methenolone enanthate) Stenbolone acetate 19-Nortestosterone derivatives: Bolandiol dipropionate Nandrolone esters (e.g., nandrolone decanoate, nandrolone phenylpropionate) Norclostebol Norclostebol acetate Oxabolone cipionate (oxabolone cypionate) Trenbolone acetate Trenbolone hexahydrobenzylcarbonate (trenbolone cyclohexylmethylcarbonate) 17α-Alkylated testosterone derivatives: Bolasterone Calusterone Chlorodehydromethyltestosterone (CDMT) Fluoxymesterone Formebolone Metandienone (methandienone, methandrostenolone) Methandriol (methylandrostenediol) Methandriol bisenanthoyl acetate Methandriol dipropionate Methandriol propionate Methyltestosterone Methyltestosterone 3-hexyl ether Oxymesterone Penmesterol Tiomesterone (thiomesterone) 17α-Alkylated dihydrotestosterone derivatives: Androisoxazole Furazabol Mebolazine (dimethazine) Mestanolone Oxandrolone Oxymetholone Stanozolol 17α-Alkylated 19-nortestosterone derivatives: Ethylestrenol Mibolerone Norethandrolone Normethandrone (methylestrenolone, normethisterone) Propetandrol (propethandrol) 17α-Vinyltestosterone derivatives: Norvinisterone (vinylnortestosterone) 17α-Ethynyltestosterone derivatives: Danazol Gestrinone Progestins (e.g., ethisterone (ethynyltestosterone), levonorgestrel, norgestrel, norethisterone (norethindrone), [[Chemistry:Lynestrlynestrenol, Norgestrienone|norgestrienone]]) Tibolone Progesterone derivatives: Medroxyprogesterone acetate

Progonadotropins

Antiestrogens (e.g., tamoxifen, Chemistry:Clomifene

| group2 = Antiandrogens
| list2 = {{Navbox|child
| groupstyle = text-align:center;
| groupwidth = 9em;

  | group1 = AR antagonists
  | list1 =

• Steroidal: Abiraterone acetate
• Canrenone
• Chlormadinone acetate
• Cyproterone acetate
• Delmadinone acetate
• Dienogest
• Drospirenone
• Medrogestone
• Megestrol acetate
• Nomegestrol acetate
• Osaterone acetate
• Oxendolone
• Potassium canrenoate
• Spironolactone

• Nonsteroidal: Apalutamide
• Bicalutamide
• Cimetidine
• Darolutamide
• Enzalutamide
• Flutamide
• Ketoconazole
• Nilutamide
• Seviteronel^†
• Topilutamide (fluridil)

  | group2 = Steroidogenesis
inhibitors

| list2 =

5α-Reductase	Alfatradiol Dutasteride Epristeride Finasteride Saw palmetto extract
Others	Abiraterone acetate Aminoglutethimide Bifluranol Cyproterone acetate Flutamide Ketoconazole Nilutamide Seviteronel† Spironolactone

  | group3 = Antigonadotropins
  | list3 =

• D₂ receptor antagonists (prolactin releasers) (e.g., domperidone, metoclopramide, risperidone, haloperidol, chlorpromazine, sulpiride)
• Estrogens (e.g., bifluranol, [[diethylstilbestrol, estradiol, estradiol esters, ethinylestradiol, ethinylestradiol sulfonate, paroxypropione)
• GnRH agonists (e.g., leuprorelin)
• GnRH antagonists (e.g., cetrorelix)
• Progestogens (incl., chlormadinone acetate, [[cyproterone acetate, hydroxyprogesterone caproate, gestonorone caproate, [[Chemistry:Medroxyprogesterone medroxyprogesterone acetate, Chemistry:Megestrol acetate|megestrol acetate]])

  | group4 = Others
  | list4 =

• Androstenedione immunogens: Androvax (androstenedione albumin)
• Ovandrotone albumin (Fecundin)

}}

| liststyle = background:#DDDDFF;

| list3 =

• ^#WHO-EM
• ^‡Withdrawn from market
• Clinical trials:
  • ^†Phase III
  • ^§Never to phase III

See also

Androgen receptor modulators

Estrogens and antiestrogens

Progestogens and antiprogestogens

List of androgens/anabolic steroids

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