Sustanon 250
A licensed blend of four testosterone esters (propionate, phenylpropionate, isocaproate and decanoate) totalling 250 mg/mL, designed to give both a fast onset and a sustained release from a single injection. Pharmacodynamically it is testosterone; the blend only shapes the release curve.
01 Overview
Sustanon 250 combines testosterone propionate (30 mg), phenylpropionate (60 mg), isocaproate (60 mg) and decanoate (100 mg) per millilitre. The short esters give a rapid initial rise while the longer esters extend the tail, so clinically it was dosed every three weeks, though this produces peaks-and-troughs that many prescribers now consider suboptimal versus more frequent dosing.
Once each ester is cleaved the circulating hormone is ordinary testosterone, so the effect and side-effect profile is identical to any other testosterone preparation. The only distinctive features are the compound release kinetics and the fixed total of 250 mg testosterone esters per mL.
02 Mechanism
The four esters are cleaved by serum esterases at different rates, releasing free testosterone over days to weeks. Testosterone activates the androgen receptor, aromatises to estradiol, and suppresses gonadotropins by negative feedback.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common | 250–500 mg/wk | IM | Split twice weekly to smooth the release curve. |
| TRT | 250 mg | IM | Historically one 250 mg ampoule every 3 weeks; more frequent smaller doses give steadier levels. |
| Strong | 500–750 mg/wk | IM | Higher doses scale side effects proportionally. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased lean massDose-dependent gain in fat-free mass, identical to any testosterone form. | +3-6 kg over a cycle | Clinical | |
| Increased strengthSupraphysiological testosterone raises maximal strength. | Clinical | ||
| Improved libido and moodRestoring testosterone improves libido, energy and mood. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Estrogenic effectsGynecomastia, water retention and blood-pressure elevation from aromatisation. | Moderate | Common at higher doses | Clinical | |
| ErythrocytosisRaised hematocrit and viscosity from androgen-stimulated erythropoiesis. | Moderate | Common | Clinical | |
| HPTA suppressionSuppression of LH/FSH, endogenous production and spermatogenesis. | Severe | Universal | Clinical |