Description
Sustanon 250 is an oily injection solution containing four different testosterone esters: Testosterone Propionate (30mg/ml), Testosterone Phenylpropionate (60mg/ml), Testosterone Isocaproate (60mg/ml) and Testosterone Decanoate (100mg/ml). Total concentration is 250mg testosterone per ml.
The concept behind the mix: each ester has a different half-life. Propionate releases quickly (half-life ~19h), Phenylpropionate medium-term (~1.5 days), Isocaproate somewhat longer (~4 days), Decanoate as long-term anchor (~15 days). The result per study reports is a “glide” effect - fast onset and more stable steady-state values than with pure Cypionate or Enanthate.
In practical anabolic research literature, Sustanon is injected either weekly or biweekly. With only weekly injection, the level profile still shows some fluctuation (E2 peaks on days 2-3), which is why some research protocols split the mix into two injections per week.
Sustanon 250 has been established in TRT research since the 1970s and, like Enanthate, is on the WHO list of essential medicines. The “Sustanon” brand belongs to Organon; the same formulation is marketed in the research market under various generic names.
You can order Sustanon 250 as an oily injection solution in 10-vial packs at 250mg/ml.
This information is for research and educational purposes only. No medical recommendations.
Risks & Safety
Sustanon 250 shares the risk profile of all testosterone esters - the four-ester format smooths the plasma levels but changes nothing about the documented physiological effects.
Documented in studies and the application literature:
- Estrogen conversion: testosterone aromatizes to estradiol. Through the Propionate peak values on days 2-3, E2 spikes are documented, along with water retention and at higher doses gynecomastia risk.
- Suppression of endogenous production: exogenous testosterone throttles the body’s own production via the HPTA axis. Testicular atrophy and reduced fertility are documented, recovery after discontinuation is not guaranteed.
- Cardiovascular: studies describe unfavorable shifts in the lipid profile (HDL falls), elevated hematocrit and an associated thrombosis risk.
- Other: acne, accelerated hair loss with genetic predisposition, mood swings. The Decanoate portion makes clearance slow if side effects occur.
Baseline bloodwork before, during and after a research protocol is strongly advised. This classification does not replace medical advice. Risk and responsibility for any actual use lie entirely with the buyer.
Studies
- Comparative pharmacokinetics of testosterone enanthate and testosterone cyclohexanecarboxylate as assessed by serum and salivary testosterone levels in normal men - International Journal of Andrology 1984, Schürmeyer et al: Comparative ester pharmacokinetics, shows how ester choice drives the serum level profile.
- Comparative pharmacokinetics of testosterone esters - Testosterone (Springer) 1998, Behre & Nieschlag: Pharmacokinetic data on the individual esters combined in the four-ester mix.
- Pharmacokinetics of Testosterone Enanthate After Intramuscular Injection for Transgender Men - Androgens: Clinical Research and Therapeutics 2020, Ichihara et al: Recent pharmacokinetics of an intramuscular testosterone ester injection.
- The Effects of Supraphysiologic Doses of Testosterone on Muscle Size and Strength in Normal Men - New England Journal of Medicine 1996, Bhasin et al: Foundational study on supraphysiologic testosterone effects on muscle size and strength.
- Testosterone dose-response relationships in healthy young men - American Journal of Physiology-Endocrinology and Metabolism 2001, Bhasin et al: Dose-response study documenting dose-dependent effects on lean mass and HDL.
