6-Bromoandrostenedione (aromatase inhibitor prohormone)
6-Bromoandrostenedione (6-bromo) is a brominated androstenedione derivative marketed as a suicidal aromatase inhibitor rather than an anabolic prohormone. Sold to raise testosterone by blocking estrogen synthesis, its human efficacy is essentially unstudied and rests on anecdote.
01 Overview
6-Bromoandrostenedione is a steroidal, irreversible ('suicidal') aromatase inhibitor structurally derived from androstenedione by bromination at the 6 position. Unlike the anabolic prohormones on this list, it is used as an ancillary aromatase inhibitor: by blocking the conversion of androgens to estrogen, it aims to nudge the testosterone-to-estrogen ratio upward and act as a mild natural-testosterone support or post-cycle aid.
It has poor oral bioavailability, and there are no controlled human trials demonstrating meaningful testosterone elevation or physique effects — reported benefits are anecdotal. Because it is a steroidal aromatase inhibitor, excessive estrogen suppression is the main theoretical risk (joint discomfort, low libido, adverse lipids), though real-world impact is limited by weak absorption. It is grouped with designer prohormones for regulatory purposes.
02 Mechanism
Irreversible steroidal aromatase inhibitor: binds and inactivates the aromatase enzyme, reducing androgen-to-estrogen conversion and modestly raising the testosterone:estrogen ratio.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common (marketed) | 90–200 mg/day | Oral | Historic labelled dosing; poor oral bioavailability limits real effect. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Reduced estrogen / higher T:E ratioAims to lower estradiol and modestly raise the testosterone-to-estrogen ratio; poorly substantiated in humans. | small | Anecdotal | |
| Mild 'natural test support'Marketed as a mild test booster or bridge; effect likely small given weak absorption. | minimal | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Excessive estrogen suppressionOver-suppression of estrogen can cause joint pain, low libido, and mood dips. | Mild | Uncommon | Anecdotal | |
| Adverse lipid shiftLow estrogen can worsen the lipid profile. | Mild | Uncommon | Anecdotal |