Oxabolone Cipionate
Oxabolone cypionate (4-hydroxy-19-nortestosterone cypionate), an obscure injectable 19-nortestosterone derivative and a metabolite of the older steroid oxabolone. Marketed historically in a few European combination products, it is a mild nandrolone-family anabolic essentially uncharacterised in modern controlled studies.
01 Overview
Oxabolone cypionate is the cypionate ester of oxabolone, 4-hydroxy-19-nortestosterone (4-hydroxyestr-4-en-17-beta-ol-3-one). It sits in the 19-nortestosterone (nandrolone) family, with a 4-hydroxy group and an estrane backbone, and was included historically in some European injectable preparations. Oxabolone also appears as a metabolite of certain other steroids, which gives it relevance in doping analysis.
It is regarded as a mild anabolic with reduced androgenicity typical of the nandrolone group, and because it is not 17-alpha-alkylated it is not markedly hepatotoxic. As a 19-nor compound it carries progestogenic and mild estrogenic character. Controlled human data are essentially nonexistent; the compound is known mainly from historical formulations, its metabolite status, and structure-based inference.
02 Mechanism
Androgen receptor agonist of the 19-nortestosterone class; the ester is cleaved to release oxabolone. The estrane backbone gives progestogenic activity and some estrogenic potential, with lower androgenicity than testosterone.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Anecdotal | 100–300 mg/wk | IM | Mild nandrolone-family compound; no controlled dosing data. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Mild lean-mass gainModest nandrolone-like anabolic effect inferred from class and vintage use. | Anecdotal | ||
| Lower androgenicityReduced androgenic effect typical of the 19-nor family. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Progestogenic side effectsLibido suppression and gynecomastia risk from progesterone-receptor activity. | Moderate | Inherent to 19-nor | Anecdotal | |
| HPTA suppressionSuppression of endogenous testosterone; nandrolone-family compounds are notably suppressive. | Moderate | Expected | Anecdotal | |
| Mild estrogenic effectsPossible water retention and gynecomastia. | Mild | Reported | Anecdotal |