Anabolic steroidAndrogenProhormoneOralTestosterone precursor

4-Androstenediol (4-AD)

Also known as 4-AD · androst-4-ene-3beta,17beta-diol · 4-androstenediol

Written by enwyReviewed 5 Aug 20262 sources0 comments

A testosterone precursor that converts to testosterone in one enzymatic step, popular in the late-1990s/early-2000s prohormone era. It raises testosterone but a large fraction also aromatises to estrogen. Now a DASCA-scheduled controlled substance in the US.

01 Overview

4-Androstenediol (androst-4-ene-3-beta,17-beta-diol) differs from the 5-ene DHEA-type diols by requiring only a single 17-beta-HSD oxidation to become testosterone, making it a comparatively efficient oral testosterone precursor. It was a mainstay of first-generation prohormone products.

Human studies from that era showed acute rises in serum testosterone but also marked increases in estradiol via aromatisation, with the usual androgenic and suppressive trade-offs. It was folded into the anabolic steroid schedules by the Designer Anabolic Steroid Control Act of 2014.

02 Mechanism

Converted to testosterone by 17-beta-hydroxysteroid dehydrogenase; a substantial fraction is aromatised to estradiol, so it acts as both an androgen and estrogen precursor.

03 Dosing

Tier	Dose	Route	Notes
Historic prohormone use	200–400 mg/day	Oral	Typical dosing in old prohormone products; oral bioavailability is poor so doses ran high.

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Acute rise in serum testosteroneOral 4-AD produced measurable short-term increases in serum testosterone in human studies.	Transient increase after dosing	Clinical
Strength/lean mass gainsUsers report modest recomposition; controlled body-composition data are weak.	Modest	Anecdotal

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Estrogenic side effectsGynecomastia risk, water retention, and elevated estradiol from aromatisation.	Moderate	Common	Clinical
HPTA suppressionSuppresses endogenous testosterone during use.	Moderate	Common	Observational

06 Legal status

United States

Schedule III controlled (DASCA 2014)

Listed as an anabolic steroid under the Designer Anabolic Steroid Control Act. · as of Jan 2026

07 References

Effects of androstenedione and androstenediol on serum testosterone and estrogenJAMA, 1999

Designer Anabolic Steroid Control Act of 2014US Public Law 113-260

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.