Oxendolone
Oxendolone is a steroidal antiandrogen and weak anabolic-androgenic steroid (16-beta-ethyl-19-nortestosterone) developed in Japan as TSAA-291 and marketed as Prostetin for benign prostatic hyperplasia. It combines weak androgenic activity with antiandrogen and progestogenic properties.
01 Overview
Oxendolone was designed as a locally acting antiandrogen for the prostate, given by intramuscular depot for benign prostatic hyperplasia. Chemically it is a 19-nortestosterone derivative with a 16-beta-ethyl group, and it displays a mixed profile: weak agonism at the androgen receptor combined with functional antiandrogen and progestogenic effects.
Unlike most entries in the oral-AAS family, oxendolone's approved route is injectable depot, and its clinical interest is urological rather than performance-related. It is included here as a member of the 19-nor androgen chemical family with distinctive antiandrogen behaviour.
02 Mechanism
Weak androgen-receptor agonist with antiandrogen activity in prostatic tissue and progestogenic action; a 16-beta-ethyl 19-nortestosterone derivative.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Clinical (BPH) | 40–80 mg/wk | IM | Depot injection for benign prostatic hyperplasia in Japanese practice. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Reduced prostate volumeAntiandrogen action shrinks hyperplastic prostate tissue. | symptomatic BPH improvement | Clinical | |
| Weak anabolic activityAndrogen-receptor agonism is weak; little muscle-building utility. | minimal | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Libido reductionLowered sexual desire consistent with antiandrogen action. | Mild | Expected | Clinical | |
| GynaecomastiaBreast tenderness and enlargement from the antiandrogen/progestogenic profile. | Moderate | Notable | Clinical |