# Testosterone Suspension

*Also known as: Test Base (injectable), Aquadose*

Ester-free injectable testosterone (water base). Very sharp peaks; dosed daily.

## Overview

Testosterone suspension is an ester-free, water-based injectable form of testosterone, the fastest-acting injectable preparation available. Without an attached ester, pure testosterone base is delivered directly into circulation after intramuscular injection, producing a sharp serum spike within hours rather than the slower release of esterified forms. The compound has a roughly 33-hour apparent half-life reflecting depot absorption and clearance, peaks within roughly 6 hours, and shows complete bioavailability, so daily injection is typical to sustain serum levels given the rapid onset and fall. Effects include rapid onset of testosterone effects and a fast clear, which suits short cycles or pre-event use, while the daily injection burden and sharp peaks drive more injection-site irritation and a larger peak-to-trough estradiol and hematocrit swing than longer esters. Harm reduction centers on sterile technique given the daily frequency and water-base contamination risk, on dividing dosing to smooth the peak, and on monitoring estradiol and hematocrit more closely than with longer esters.

## Pharmacokinetics

- **Model tier:** advanced
- **Half-life:** 1.4 days (33 hours)
- **Cmax:** 900 ng/dL
- **Tmax:** 0.3 days
- **Bioavailability:** 100%

## Dosing

- **Default dose:** 50 mg
- **Typical range:** 25–100 mg
- **Units:** ng/dL

## Harm reduction

- **Aromatizes:** Yes
- **DHT derivative:** No
- **Injection frequency:** Daily

## Source

- **Label:** RMTC equine PK study
- **URL:** https://rmtcnet.com/wp-content/uploads/2015/07/An_interlaboratory_study_of_the_pharmacokinetics_of_testosterone_following_intramuscular_administration_to_Thoroughbred_horses1.pdf
- **Notes:** Cmax calibrated to ng/dL serum peak (ester-free water base → sharp spike).

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**Plot:** https://anabolicdex.com/plot?compound=testosterone-suspension