Testosterone Cypionate
Depo-Testosterone
Half-life
8 days
Time to Peak
36 hr
Steady State
~40 days
Bioavailability
100%
Dose Range
50–300 mg
Frequency
Weekly
Overview
Testosterone Cypionate is the most commonly prescribed testosterone ester in the US for TRT. It's an oil-based injectable with a half-life of about 8 days, allowing for weekly or twice-weekly dosing.
Mechanism of Action
Depot injection releases testosterone via ester hydrolysis. Testosterone binds androgen receptors, promoting anabolic effects and maintaining male sex characteristics.
Dosing Information
| Route | Dose Range | Half-life | Tmax | Frequency |
|---|---|---|---|---|
| Intramuscular (IM) | 50–300 mg | 8 days | 36 hr | Weekly, Every 2 weeks, Twice weekly |
| Subcutaneous (SubQ) | 25–200 mg | 8 days | 2 days | Twice weekly, Every other day, Weekly |
Common Side Effects
- · Acne
- · Hair thinning (androgenic alopecia)
- · Increased hematocrit/polycythemia
- · Elevated estradiol (aromatization)
- · Testicular atrophy (without HCG)
- · Injection site pain (PIP)
- · Mood changes
- · Sleep apnea (rare)
Monitoring Recommendations
Total T, Free T, Estradiol (sensitive), CBC with hematocrit, and PSA every 3-6 months for the first year, then annually. Lipid panel at baseline and annually. Liver function tests at baseline.
Storage & Handling
Room Temperature
Store at 20-25°C (68-77°F). Excursions permitted 15-30°C.
General
Protect from light. Do not refrigerate or freeze. Discard multi-dose vials 28 days after first puncture per USP <797>.
Community Notes
SubQ injection is increasingly popular — smaller needle, less PIP, similar absorption. Most TRT-optimized protocols use 2x/week to reduce estradiol spikes and keep levels more stable. Warming the oil to body temperature before injecting reduces viscosity and PIP.
Used in Regimens
11 regimensBeginner First Cycle (Harm Reduction)
Conservative beginner AAS cycle for harm reduction: testosterone-only at moderate dose with on-cycle HCG and post-cycle Nolvadex. Designed to minimise risk while providing meaningful data about individual response to testosterone before adding other compounds.
Test Cyp 300mg/week (lower than community 500mg — harm reduction dose).
Beginner Test-Only Blast + PCT
12-week testosterone cypionate blast at beginner doses with on-cycle HCG for testicular maintenance, followed by a 2-week clearance window and 4-week Nolvadex PCT. The gold-standard first cycle.
Blast and Cruise
Alternating between a blast (supraphysiological testosterone dose for 8–16 weeks) and a cruise (return to TRT dose indefinitely). Avoids the PCT phase entirely. Common among experienced TRT users and advanced bodybuilders who do not intend to discontinue testosterone.
Blast phase: beginner blast protocol 300–500mg/week for 12 weeks.
Daily SubQ Micro-Dose TRT
Testosterone cypionate administered daily subcutaneously at low volume (0.1–0.15mL/day). Produces the most stable serum testosterone and oestradiol levels of any injectable protocol, closely mimicking the natural circadian rhythm. Favoured by those sensitive to hormonal fluctuations.
Daily micro-dose SubQ. Typical total weekly dose 70–140mg split 7 ways.
Low-Dose Testosterone — Non-Binary / Microdose
Testosterone cypionate or enanthate at micro-dose (typically 20–50mg/week) for non-binary, genderqueer, or transmasculine individuals seeking partial masculinisation. Lower doses produce selective changes — increased libido and clitoral growth typically first; voice changes and significant hair growth require higher doses and longer duration.
Transmasc T Cyp microdose protocol 20–50mg/week.
Standard TRT Protocol
Evidence-based testosterone replacement with HCG for testicular maintenance and optional low-dose aromatase inhibitor. The most common TRT stack recommended by progressive clinicians.
Data Sources
- FDA Label Depo-Testosterone FDA Prescribing Information
- Peer-reviewed Schulte-Beerbuhl & Nieschlag 1980
- Peer-reviewed Al-Futaisi et al. 2006 — SubQ bioequivalence
Related Tools
Track Testosterone Cypionate with Doseline
Reminders, medication level charts, injection site rotation, and protocol tracking — all free, all private.
Join the waitlistDoseline provides informational tools only. It is not a medical device and does not provide medical advice. Always consult a qualified healthcare provider.