Anabolic steroidAndrogenTestosterone esterInjectable
Testosterone Cypionate
Also known as Test C · Depo-Testosterone · Cyp
A long-acting testosterone ester near-identical in practice to enanthate, differing only in a marginally longer half-life. The most common TRT ester in the United States.
01 Overview
Cypionate is an eight-carbon ester of testosterone. Once cleaved it is simply testosterone, so its entire effect and side-effect profile matches enanthate — the choice between them is regional habit, not pharmacology.
The slightly longer ester means marginally flatter serum levels, but the difference is small enough to be clinically irrelevant for most.
02 Mechanism
Identical to testosterone once the ester is cleaved: androgen-receptor agonism, with aromatisation to oestradiol and 5α-reduction to DHT accounting for most of the side-effect profile.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Therapeutic | 75–200 mg/wk | IM | Standard US TRT range, usually split twice weekly. |
| Common | 300–500 mg/wk | IM | Typical first non-medical protocol; interchangeable with enanthate. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased lean body massSame dose-response as other testosterone esters | +3–6 kg / 10 wk | Clinical | |
| Improved libido and moodReliable where baseline testosterone is low | Marked in hypogonadism | Clinical | |
| Increased bone mineral densityOver 12–36 months of therapy | +3–8% | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| ErythrocytosisRaised haematocrit, as with all testosterone. The most consistently abnormal lab value. | Severe | Common | Clinical | |
| HPTA suppressionTesticular atrophy and suppressed spermatogenesis. | Severe | Universal | Clinical |
06 Legal status
United States
Schedule III controlled
Prescription only · as of Jan 2026
United Kingdom
Class C controlled
Personal possession lawful · as of Jan 2026
07 References
Testosterone therapy in men with hypogonadism: Endocrine Society guidelineJ Clin Endocrinol Metab, 2018
08 Discussion0 comments
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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.