# Estradiol Cypionate

*Also known as: E2 Cyp, Depo-Estradiol*

Injectable estradiol cypionate used in feminizing HRT.

## Overview

Estradiol cypionate (Depo-Estradiol) is an injectable estradiol ester used in feminizing hormone therapy and for menopausal hormone replacement. The cypionate ester is cleaved slowly by tissue esterases to release free 17-beta-estradiol from the intramuscular depot, producing sustained levels over roughly a week per injection. The compound has a roughly 90-hour half-life, peaks within roughly 17 hours, and shows about 60% bioavailability, supporting weekly to twice-weekly dosing depending on target estradiol level and tolerance of peak-to-trough variation. Effects include stable parenteral estradiol exposure without the first-pass metabolic load of oral dosing, while the main risks are supraphysiological estradiol peaks driving mood swings, breast tenderness, and thrombosis risk if levels are pushed too high. Harm reduction centers on titrating to estradiol bloodwork rather than fixed dose and on monitoring estradiol, liver function, and clotting risk factors during therapy.

## Pharmacokinetics

- **Model tier:** advanced
- **Half-life:** 3.7 days (89.650000008 hours)
- **Cmax:** 2.8 pg/mL
- **Tmax:** 0.7 days
- **Bioavailability:** 60%

## Dosing

- **Default dose:** 5 mg
- **Typical range:** 2–10 mg
- **Units:** pg/mL

## Source

- **Label:** ScienceDirect (E2 Cyp PK)
- **URL:** https://www.sciencedirect.com/science/article/abs/pii/S073170851831464X

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**Canonical URL:** https://anabolicdex.com/compounds/estradiol-cypionate
**Plot:** https://anabolicdex.com/plot?compound=estradiol-cypionate