Testosterone propionate is a synthetic anabolic steroid with a slower release and a short half-life. Testosterone propionate is a derivative of the androstane steroid testosterone, specifically formulated as the 17β-propionate ester. Initially created by Watson Laboratories, it received FDA approval on February 5, 1974. Its primary use is for androgen replacement therapy. It is specifically approved for treating male hypogonadism, breast cancer, low libido, delayed puberty in boys, and symptoms associated with menopause.
BRAND NAMES
Testoviron-available in an injectable solution for intramuscular administration. Testosterone propionate must be injected every 2 to 3 days to maintain stable hormone levels.
MECHANISM OF ACTION
Testosterone propionate is a prodrug and potent androgen that is converted into free testosterone after being injected. Once converted, the testosterone activates androgen receptors inside the body's cells, regulating gene transcription and increasing protein synthesis. Some testosterone is also converted by enzymes into dihydrotestosterone (a more potent androgen) or estradiol (an estrogen), triggering secondary androgenic and estrogenic effects throughout the body. This activity promotes muscle growth, bone density, and the development of male sex characteristics.
PHARMACOKINETICS
Absorption
Testosterone propionate is a modified form of testosterone in which the hormone is esterified, and it is usually delivered via intramuscular injection in an oil-based solution. The esterification with a short-chain propionate group modifies the absorption rate of the hormone. This makes the drug hydrophobic and allows for a slow, sustained release from the injection site, unlike un-modified testosterone, which has a very short half-life.
Distribution
The reported volume of distribution for testosterone propionate is not a standard human physiological parameter, but rather a value derived from a single specific study, which indicates a range of 75–120 L/kg.
Metabolism
Testosterone propionate is a synthetic androgen that functions as a prodrug of testosterone. It is rapidly hydrolyzed into active testosterone after administration, primarily through intramuscular injection. The liver then metabolizes the free testosterone through two main pathways: conversion by 5-alpha reductase to the more potent dihydrotestosterone (DHT) and conversion by aromatase to estradiol. The majority of testosterone and its metabolites are then conjugated and excreted in the urine. Due to its relatively short half-life of about 20 hours, testosterone propionate requires frequent injections to maintain stable levels in the body.
Excretion
Approximately 90% of a testosterone dose is eliminated through urine, while around 6% is excreted in feces.
PHARMACODYNAMICS
Testosterone propionate is a short-acting prodrug of testosterone that acts as an agonist for the androgen receptor (AR). After administration, it is rapidly converted into free testosterone, which is responsible for its androgenic and anabolic effects.
ADMINISTRATION
Testosterone propionate is a synthetic, oil-based testosterone ester administered via intramuscular injection to treat conditions like male hypogonadism and delayed puberty. It is a fast-acting hormone with a short half-life, which means injections are required more frequently than with other testosterone esters to maintain stable levels.
DOSAGE AND STRENGTH
Testosterone propionate is mainly supplied as an oil-based formulation intended for intramuscular injection.
The recommended dosage of testosterone propionate is 25 to 50 mg (approximately 2 mg/kg), administered intramuscularly at three-week intervals, for a maximum of three doses before surgery.
DRUG INTERACTIONS
Testosterone propionate interacts significantly with several medication classes, including anticoagulants like warfarin, which increases bleeding risk, and corticosteroids, which can cause fluid retention. Because it is metabolized by the CYP3A4 enzyme, testosterone can also affect the concentration of drugs processed by the same pathway. Furthermore, it can enhance the blood sugar-lowering effect of insulin and other diabetes medications. Therefore, informing your doctor about all medications and supplements is crucial before beginning testosterone therapy.
FOOD INTERACTIONS
No direct food interactions are known for testosterone propionate, as it is administered via intramuscular injection and bypasses the digestive system. However, certain dietary choices can affect your overall hormonal health and should be considered, especially if you are taking testosterone replacement therapy (TRT).
CONTRAINDICATIONS
The main contraindications for testosterone propionate and other forms of testosterone therapy are certain cancers and serious cardiac, liver, or kidney diseases. Patients with these conditions should not use this medication.
SIDE EFFECTS
Injection site reactions.
Dermatological issues.
Fluid retention.
Mood changes.
Sleep apnea.
Weight gain.
Headaches.
Prostate cancer risk.
Gynecomastia.
Fertility and testicular changes.
Painful or prolonged erections.
OVER DOSE
Taking a very high dose of testosterone propionate at one time can cause serious, immediate effects, including:
Blurred vision or temporary blindness.
Seizures.
Severe and sudden headache.
Slurred speech or an inability to speak.
Weakness or numbness affecting one side of the body.
Chest pain, pressure, or shortness of breath.
Nausea and vomiting.
Sudden weakness or faintness.
TOXICITY
Testosterone propionate toxicity arises from the use of high doses and unmonitored therapy, which can lead to serious cardiovascular, hepatic, and psychiatric complications. The risk of toxicity is especially high when the substance is misused for performance enhancement rather than under medical supervision.
