# Testosterone Propionate

*Also known as: Test P, TP*

Short-acting ester with sharp peaks; requires frequent injection. Useful for frontloading.

## Overview

Testosterone propionate is a short-acting injectable ester of testosterone, where the 3-carbon propionate chain slows release from the injection depot. Once esterases cleave the propionate group, free testosterone enters circulation and binds the androgen receptor, driving the same gene-expression changes as endogenous testosterone (protein synthesis, nitrogen retention, erythropoiesis). The dataset pegs its half-life at 2 days (48 hours), with serum Cmax near 700 ng/dL at the default 100 mg dose and a Tmax around 25 hours. Because of that fast clearance, research and clinical TRT protocols inject it daily to every other day to avoid sharp peaks and troughs. It aromatizes to estradiol, so estrogenic side effects need monitoring, though it is not hepatotoxic since it skips first-pass metabolism.

## Pharmacokinetics

- **Model tier:** advanced
- **Half-life:** 2.0 days (48 hours)
- **Cmax:** 700 ng/dL
- **Tmax:** 1.1 days
- **Bioavailability:** 84%

## Dosing

- **Default dose:** 100 mg
- **Typical range:** 50–150 mg
- **Units:** ng/dL

## Harm reduction

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

## Detection time (anti-doping)

- **Window:** 14–21 days post-last-dose
- **Target metabolite:** Testosterone/epitestosterone ratio (T/E) + GC/C/IRMS confirmation
- **Assay:** GC-MS/MS (profile) + GC/C/IRMS
- **Notes:** Short-acting ester (~1-day half-life); T/E normalizes within ~2–3 weeks. Blood-ester detection 4–5 days (Forsdahl 2015).

## Source

- **Label:** JCEM (testosterone propionate-19-d3)
- **URL:** https://academic.oup.com/jcem/article-abstract/63/6/1361/2674622
- **Notes:** Cmax calibrated to ng/dL serum peak at the default dose.

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