PharmaceuticalInjectableEstrogenEstradiol ester

Estradiol Enanthate

Also known as EEn · Perlutal (component) · Topasel (component)

Written by enwyReviewed 5 Aug 20261 sources0 comments

Long-acting injectable estradiol ester, historically paired with dihydroxyprogesterone acetophenide in the monthly injectable contraceptive Perlutal/Topasel. Provides extended estradiol release for HRT and feminization.

01 Overview

Estradiol enanthate is a slow-release ester of 17-beta-estradiol. Its best-documented use is as the estrogen component of once-monthly combined injectable contraceptives popular in Latin America. It is also used in feminizing hormone therapy where a long dosing interval is desired.

Because data in transfeminine care come largely from smaller series and contraceptive literature, dosing is individualised and monitored by serum estradiol.

02 Mechanism

Enanthate ester hydrolyses to 17-beta-estradiol, activating estrogen receptors and suppressing the HPG axis.

03 Dosing

Tier	Dose	Route	Notes
Feminizing HRT	3–10 mg/wk	IM	Given every 1-2 weeks; titrate to serum estradiol.

04 Effects

Effect	Magnitude	Evidence
FeminizationBreast development and fat redistribution as with other estradiol esters.		Observational
Long dosing intervalExtended release allows less frequent injection.		Observational

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Venous thromboembolismClass estrogen clotting risk.	Severe	Uncommon	Clinical
Estradiol overshootLong ester makes correcting high levels slow.	Moderate	Common with large depots	Observational

06 Legal status

United States

Prescription drug

Not FDA-approved as standalone in US; Rx where marketed. · as of Jan 2026

07 References

Once-a-month combined injectable contraceptives: efficacy and reasons for discontinuation (WHO)Contraception, WHO trials

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.