Anandrogen oranabolic steroid ester is anester of anandrogen/anabolic steroid (AAS) such as the naturaltestosterone ordihydrotestosterone (DHT) or the syntheticnandrolone (19-nortestosterone). Esterification renders AAS intometabolism-resistantprohormones of themselves, improvingoralbioavailability, increasinglipophilicity, and extending theelimination half-life (which necessitates less frequent administration). In addition, withintramuscular injection, AAS esters are absorbed more slowly into the body, thus further improving the elimination half-life. Aside from differences inpharmacokinetics (e.g.,duration), these esters essentially have the same effects as the parent drugs.[1] They are used inandrogen replacement therapy (ART), among other indications. Examples of androgen esters includetestosterone esters such astestosterone cypionate,testosterone enanthate,testosterone propionate, andtestosterone undecanoate andnandrolone esters such asnandrolone decanoate andnandrolone phenylpropionate.
| 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 viai.m. injection.Footnotes:a =TP,TV, andTUe.b =TP andTKL.c =TP,TPP,TiCa, andTD.d = Studied but never marketed.e = Developmental code names.Sources: See template. | |||
| Testosterone ester | Form | Route | TmaxTooltip Time to peak levels | t1/2Tooltip Elimination half-life | MRTTooltip 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 | 10 days | 4.5 days | 8.5 days |
| Testosterone undecanoate | Tea seed oil solution | Intramuscular injection | 13.0 days | 20.9 days | 34.9 days |
| Testosterone undecanoate | Castor oil solution | Intramuscular injection | 11.4 days | 33.9 days | 36.0 days |
| Testosterone buciclatea | Aqueous suspension | Intramuscular injection | 25.8 days | 29.5 days | 60.0 days |
| Notes:Testosterone cypionate has similar pharmacokinetics toTestosterone enanthate.Footnotes:a = Never marketed.Sources: See template. | |||||
| Androgen | Structure | Ester | Relative mol. weight | Relative T contentb | logPc | ||||
|---|---|---|---|---|---|---|---|---|---|
| Position(s) | Moiet(ies) | Type | Lengtha | ||||||
| Testosterone |  | – | – | – | – | 1.00 | 1.00 | 3.0–3.4 | |
| Testosterone propionate |  | C17β | Propanoic acid | Straight-chain fatty acid | 3 | 1.19 | 0.84 | 3.7–4.9 | |
| Testosterone isobutyrate |  | C17β | Isobutyric acid | Branched-chain fatty acid | – (~3) | 1.24 | 0.80 | 4.9–5.3 | |
| Testosterone isocaproate |  | C17β | Isohexanoic acid | Branched-chain fatty acid | – (~5) | 1.34 | 0.75 | 4.4–6.3 | |
| Testosterone caproate |  | C17β | Hexanoic acid | Straight-chain fatty acid | 6 | 1.35 | 0.75 | 5.8–6.5 | |
| Testosterone phenylpropionate |  | C17β | Phenylpropanoic acid | Aromatic fatty acid | – (~6) | 1.46 | 0.69 | 5.8–6.5 | |
| Testosterone cypionate |  | C17β | Cyclopentylpropanoic acid | Cyclic carboxylic acid | – (~6) | 1.43 | 0.70 | 5.1–7.0 | |
| Testosterone enanthate |  | C17β | Heptanoic acid | Straight-chain fatty acid | 7 | 1.39 | 0.72 | 3.6–7.0 | |
| Testosterone decanoate |  | C17β | Decanoic acid | Straight-chain fatty acid | 10 | 1.53 | 0.65 | 6.3–8.6 | |
| Testosterone undecanoate | | C17β | Undecanoic acid | Straight-chain fatty acid | 11 | 1.58 | 0.63 | 6.7–9.2 | |
| Testosterone buciclated |  | C17β | Bucyclic acide | Cyclic carboxylic acid | – (~9) | 1.58 | 0.63 | 7.9–8.5 | |
| Footnotes:a = Length ofester incarbonatoms forstraight-chain fatty acids or approximate length of ester in carbon atoms foraromatic orcyclic fatty acids.b = Relative testosterone content by weight (i.e., relativeandrogenic/anabolicpotency).c = Experimental or predictedoctanol/water partition coefficient (i.e.,lipophilicity/hydrophobicity). Retrieved fromPubChem,ChemSpider, andDrugBank.d = Never marketed.e =Bucyclic acid =trans-4-Butylcyclohexane-1-carboxylic acid.Sources: See individual articles. | |||||||||
| 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 ofester incarbonatoms forstraight-chain fatty acids or approximate length of ester in carbon atoms foraromatic fatty acids.b = Relative androgen/anabolic steroid content by weight (i.e., relativeandrogenic/anabolicpotency).c =Duration byintramuscular orsubcutaneous injection inoil solution.d = Never marketed.Sources: See individual articles. | |||||||||