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Androgen ester

Testosterone undecanoate, an ester of testosterone and one of the most widely used androgen esters.

An androgen or anabolic steroid ester is an ester of an androgen/anabolic steroid (AAS) such as the natural testosterone or dihydrotestosterone (DHT) or the synthetic nandrolone (19-nortestosterone). Esterification renders AAS into metabolism-resistant prohormones of themselves, improving oral bioavailability, increasing lipophilicity, and extending the elimination half-life (which necessitates less frequent administration). In addition, with intramuscular injection, AAS esters are absorbed more slowly into the body, further improving the elimination half-life. Aside from differences in pharmacokinetics (e.g., duration), these esters essentially have the same effects as the parent drugs.[1] They are used in androgen replacement therapy (ART), among other indications. Examples of androgen esters include testosterone esters such as testosterone cypionate, testosterone enanthate, testosterone propionate, and testosterone undecanoate and nandrolone esters such as nandrolone decanoate and nandrolone phenylpropionate.

Parenteral durations of androgens/anabolic steroids

Compound Brand name(s) Type Duration
Testosterone (aq. susp.) Andronaq, Sterotate, Virosterone Androgen 2–3 days
Testosterone propionate Androteston, Perandren, Testoviron Androgen 3–4 days
Testosterone phenylpropionate Testolent Androgen 8 days
Testosterone isobutyrate (aq. susp.) Agovirin Depot, Perandren M Androgen 14 days
Mixed testosterone estersa Triolandren Androgen 10–20 days
Mixed testosterone estersb Testosid Depot Androgen 14–20 days
Testosterone enanthate Delatestryl Androgen 14–20 days
Testosterone cypionate Depovirin Androgen 14–20 days
Mixed testosterone estersc Sustanon 250 Androgen 28 days
Testosterone undecanoate Aveed, Nebido Androgen 100 days
Testosterone buciclate (aq. susp.)d 20 Aet-1, CDB-1781e Androgen 90–120 days
Nandrolone phenylpropionate Durabolin Anabolic 10 days
Nandrolone decanoate Deca Durabolin Anabolic 21 days
Methandriol (aq. susp.) Notandron, Protandren Androgen 8 days
Methandriol bisenanthoyl acetate Notandron Depot Androgen 16 days
Metenolone acetate Primobolan Anabolic 3 days
Metenolone enanthate Primobolan Depot Anabolic 14 days
Note: All are via i.m. injection of oil solution unless noted otherwise. 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.

Pharmacokinetics of testosterone esters

Testosterone ester Form Route of administration Elimination half-life Mean residence time
Testosterone undecanoate Oil-filled capsules Oral 1.6 hours 3.7 hours
Testosterone propionate Oil solution Intramuscular injection 0.8 days 1.5 days
Testosterone enanthate Castor oil solution Intramuscular injection 4.5 days 8.5 days
Testosterone undecanoate Tea seed oil solution Intramuscular injection 20.9 days 34.9 days
Testosterone undecanoate Castor oil solution Intramuscular injection 33.9 days 36.0 days
Testosterone buciclatea Aqueous suspension Intramuscular injection 29.5 days 60.0 days
Notes: Testosterone cypionate has very similar pharmacokinetics to TE. Footnotes: a = Never marketed. Sources: See template.

Structural properties of major testosterone esters

Androgen Structure Ester Relative
mol. weight
Relative
T contentb
Durationc
Position Moiety Type Lengtha Rank Group
Testosterone
Testosteron.svg
1.00 1.00 11 Short
Testosterone propionate
Testosterone propionate.svg
C17β Propanoic acid Straight-chain fatty acid 3 1.19 0.84 10 Short
Testosterone isobutyrate
Testosterone isobutyrate.svg
C17β Isobutyric acid Aromatic fatty acid – (~3) 1.24 0.80 9 Moderate
Testosterone cypionate
Testosterone cypionate.svg
C17β Cyclopentylpropanoic acid Aromatic fatty acid – (~6) 1.43 0.70 8 Moderate
Testosterone phenylpropionate
Testosterone phenpropionate.svg
C17β Phenylpropanoic acid Aromatic fatty acid – (~6) 1.46 0.69 7 Moderate
Testosterone isocaproate
Testosterone isocaproate.svg
C17β Isohexanoic acid Branched-chain fatty acid – (~5) 1.34 0.75 6 Moderate
Testosterone caproate
Testosterone caproate.svg
C17β Hexanoic acid Straight-chain fatty acid 6 1.35 0.75 5 Moderate
Testosterone enanthate
Testosterone enanthate.svg
C17β Heptanoic acid Straight-chain fatty acid 7 1.39 0.72 4 Moderate
Testosterone decanoate
Testosterone decanoate.svg
C17β Decanoic acid Straight-chain fatty acid 10 1.53 0.65 3 Long
Testosterone undecanoate
Testosterone undecanoate.svg
C17β Undecanoic acid Straight-chain fatty acid 11 1.58 0.63 2 Long
Testosterone buciclated
Testosteronebuciclate structure.png
C17β Bucyclic acide Aromatic carboxylic acid – (~9) 1.58 0.63 1 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 testosterone content by weight (i.e., relative androgenic/anabolic potency). c = Duration by intramuscular or subcutaneous injection in oil solution (except TiB and TB, which are in aqueous suspension). d = Never marketed. e = Bucyclic acid = trans-4-Butylcyclohexane-1-carboxylic acid. Sources: See individual articles.

Structural properties of major anabolic steroid esters

Anabolic steroid Structure Ester Relative
mol. weight
Relative
AAS contentb
Durationc
Position Moiety Type Lengtha
Boldenone undecylenate
Boldenone undecylenate.svg
C17β Undecylenic acid Straight-chain fatty acid 11 1.58 0.63 Long
Drostanolone propionate
Drostanolone propionate.svg
C17β Propanoic acid Straight-chain fatty acid 3 1.18 0.84 Short
Metenolone acetate
Metenolone acetate.svg
C17β Ethanoic acid Straight-chain fatty acid 2 1.14 0.88 Short
Metenolone enanthate
Metenolone enanthate.png
C17β Heptanoic acid Straight-chain fatty acid 7 1.37 0.73 Long
Nandrolone decanoate
Nandrolone decanoate.svg
C17β Decanoic acid Straight-chain fatty acid 10 1.56 0.64 Long
Nandrolone phenylpropionate
Nandrolone phenylpropionate.svg
C17β Phenylpropanoic acid Aromatic fatty acid – (~6–7) 1.48 0.67 Long
Trenbolone acetate
Trenbolone acetate.svg
C17β Ethanoic acid Straight-chain fatty acid 2 1.16 0.87 Short
Trenbolone enanthated
Trenbolone enanthate.svg
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.

See also

References

  1. ^ Richard Lawrence Miller (2002). The Encyclopedia of Addictive Drugs. Greenwood Publishing Group. pp. 416–. ISBN 978-0-313-31807-8.

Further reading