Anabolic steroidAndrogenTestosterone esterInjectable

Testosterone Phenylpropionate

Also known as Test PP · TPP

Written by enwyReviewed 15 Jul 20262 sources0 comments

A medium-short injectable testosterone ester, best known as one of the four esters in Sustanon. Once cleaved it is bioidentical testosterone, so the effect and side-effect profile is testosterone's; the phenylpropionate ester sits between propionate and enanthate in duration.

01 Overview

Testosterone phenylpropionate (TPP) uses the same phenylpropionic acid ester found in nandrolone phenylpropionate. Its release kinetics are intermediate — longer than propionate but shorter than enanthate — giving a duration of action of roughly a week.

As with all testosterone esters, the ester only governs release rate; the liberated hormone and therefore the pharmacodynamics are identical to testosterone. TPP is rarely used as a standalone product outside blends but is a defined component of Sustanon 250.

02 Mechanism

Esterases cleave the phenylpropionate ester to free testosterone, which activates the androgen receptor and aromatises to estradiol, while suppressing endogenous gonadotropins by negative feedback.

03 Dosing

Tier	Dose	Route	Notes
Common	300–500 mg/wk	IM	Injected every 2-3 days due to intermediate half-life.
Strong	500–700 mg/wk	IM	Higher doses scale side effects proportionally.

Ester comparison

Ester	Half-life	Injection freq.	Testosterone by mass

04 Effects

Effect	Magnitude	Evidence
Increased lean massDose-dependent gain in fat-free mass, identical to any testosterone form once the ester is cleaved.	+3-6 kg over a cycle	Clinical
Increased strengthSupraphysiological testosterone increases maximal strength dose-dependently.		Clinical
Improved libido and moodRaising serum testosterone improves libido and mood, especially from a hypogonadal baseline.		Clinical

05 Side effects

Effect	Severity	Frequency	Evidence
Estrogenic effectsGynecomastia, water retention and blood-pressure rise from aromatisation to estradiol.	Moderate	Common at higher doses	Clinical
ErythrocytosisElevated hematocrit and blood viscosity from androgen-stimulated erythropoiesis.	Moderate	Common	Clinical
HPTA suppressionSuppression of LH/FSH with loss of endogenous production and fertility.	Severe	Universal	Clinical

06 Legal status

United Kingdom

Class C

as of Jan 2026

United States

Schedule III controlled substance

Prescription required. · as of Jan 2026

07 References

Pharmacokinetics of Sustanon and its component estersPubMed search

Testosterone dose-response relationships in healthy young menAm J Physiol Endocrinol Metab, 2001

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.