# Boldenone Undecylenate (Equipoise)

*Also known as: EQ, Equipoise, Boldenone*

Equipoise; long half-life, slow steady gains. Notorious for long detection times.

## Overview

Boldenone undecylenate (Equipoise, EQ) is a long-acting injectable androgen originally developed for veterinary use (as Parenabol briefly in humans, then as Equipoise for horses). It is a testosterone analog with a double bond at the 1,4 position, which reduces both androgenic and estrogenic activity relative to testosterone, though it still aromatizes weakly. It binds the androgen receptor and drives steady erythropoiesis (the basis for the reputation for endurance and slow, lean gains). Its 14-day half-life produces a slow rise and a very long tail, so research protocols have used 1-2 injections per week with a multi-week run-up to steady state. Hepatotoxicity is rated none and the side-effect profile is comparatively mild. HPTA suppression is real but slower than with shorter esters.

## Pharmacokinetics

- **Model tier:** advanced
- **Half-life:** 14.0 days (336 hours)
- **Cmax:** 600 ng/dL
- **Tmax:** 6.0 days
- **Bioavailability:** 63%

## Dosing

- **Default dose:** 300 mg
- **Typical range:** 200–600 mg
- **Units:** ng/dL

## Harm reduction

- **Aromatizes:** Yes
- **DHT derivative:** No
- **Injection frequency:** 2×/week

## Detection time (anti-doping)

- **Window:** 90–180 days post-last-dose
- **Target metabolite:** 18-nor-17β-hydroxymethyl-17α-methyl-androst-1,4,13-trien-3-one
- **Assay:** LC-MS/MS
- **Notes:** Long-term metabolite detectable ~26 days (single-dose). Multi-dose regimens extend window. Sulfo-conjugated metabolites under investigation for extended detection.

## Source

- **Label:** PubMed (boldenone PK)
- **URL:** https://pubmed.ncbi.nlm.nih.gov/17348894/

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