Estradiol Cypionate
Depo-Estradiol
Half-life
9 days
Time to Peak
3.5 days
Steady State
~45 days
Bioavailability
100%
Dose Range
2–5 mg
Frequency
Weekly
Overview
Estradiol Cypionate is a long-acting injectable estrogen with a half-life of about 8 days, allowing for less frequent dosing (every 1-2 weeks). Popular in feminizing HRT for its convenience and stable levels.
Mechanism of Action
Prodrug: cypionate ester is hydrolyzed in vivo, releasing active 17β-estradiol. Binds estrogen receptors (ERα and ERβ).
Dosing Information
| Route | Dose Range | Half-life | Tmax | Frequency |
|---|---|---|---|---|
| Intramuscular (IM) | 2–5 mg | 9 days | 3.5 days | Weekly, Every 2 weeks |
Common Side Effects
- · Breast tenderness
- · Mood changes
- · Headache
- · Injection site reactions
- · Weight redistribution
- · Nausea (less common than oral)
Monitoring Recommendations
Same monitoring as Estradiol Valerate. Draw labs at trough for accurate assessment.
Storage & Handling
Room Temperature
Store at 20-25°C.
General
Protect from light. Do not freeze.
Community Notes
Less widely available than Valerate — sometimes needs compounding. The longer half-life means more stable levels with less frequent injections. Some users combine with a shorter-acting estrogen for fine-tuning.
Used in Regimens
Estradiol Cypionate is not currently part of any catalog regimen.
Data Sources
- Peer-reviewed Sierra-Ramirez et al. — Pharmacokinetics of estradiol cypionate after single IM injection
- FDA Label Depo-Estradiol (estradiol cypionate) — FDA Prescribing Information
Related Tools
Track Estradiol Cypionate with Doseline
Reminders, medication level charts, injection site rotation, and protocol tracking — all free, all private.
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