Testosterone Topical

Sex Hormones & TRT

AndrogelTestogelFortestaAxironTestim

Overview

Testosterone topical, commonly known under brand names such as Androgel, Testogel, and Fortesta, is a synthetic form of the endogenous hormone testosterone. It is primarily produced in the testes in males and in smaller amounts in the ovaries and adrenal glands in females. Testosterone belongs to the androgen class of hormones, which are steroid hormones derived from cholesterol. It plays a crucial role in the development and maintenance of male secondary sexual characteristics and is also involved in various physiological processes in both sexes.

The primary physiological roles of testosterone include the regulation of libido, bone density, muscle mass, and the production of red blood cells. Researchers have extensively studied testosterone for its effects on mood, cognition, and cardiovascular health. In clinical settings, testosterone replacement therapy (TRT) is used to treat hypogonadism and other conditions associated with low testosterone levels.

Testosterone exerts its effects by binding to androgen receptors, which are distributed throughout various tissues in the body. Upon binding, the hormone-receptor complex translocates to the cell nucleus, where it influences the transcription of specific genes, leading to the expression of proteins that mediate its physiological effects. This pathway is critical for the development of male characteristics and the maintenance of muscle and bone health.

Pharmacokinetically, testosterone topical formulations are designed to be absorbed through the skin, providing a steady release of the hormone into the bloodstream. The transdermal route avoids first-pass metabolism in the liver, enhancing bioavailability compared to oral formulations. Researchers have observed that steady-state levels are typically achieved within 24-48 hours of application.

Clinically, testosterone topical is used in testosterone replacement therapy for individuals with low testosterone levels. It is approved by regulatory agencies such as the FDA for this purpose. However, its use is regulated due to potential side effects and the risk of abuse. Researchers continue to study its long-term effects and optimal therapeutic protocols to maximize benefits and minimize risks.

Mechanism of Action

Testosterone acts primarily through binding to androgen receptors, which are intracellular receptors that, upon activation, influence gene expression. This leads to a cascade of biological effects, including the promotion of male secondary sexual characteristics and anabolic effects on muscle and bone tissue.

Half-Life & Pharmacokinetics

Endogenous	Circulating half-life ~70 minutes
Transdermal	Steady-state after 24-48h
Oral	Poor bioavailability due to first-pass

Transdermal formulations avoid first-pass metabolism, enhancing bioavailability compared to oral forms.

Storage

Temperature

Store at room temperature (15-30°C)

Light

Protect from light

Form

Gel formulation stable for extended periods

Notes

Ensure cap is tightly closed to prevent evaporation.

Solubility

Testosterone is soluble in ethanol, which is often used in gel formulations to facilitate transdermal absorption.

Legal Status

🇩🇪DE

Prescription only (verschreibungspflichtig), not listed under BtMG.

🇺🇸US

FDA approved for TRT, Schedule III controlled substance, prescription required.

🇦🇺AU

Schedule 4 (S4) prescription-only medicine.

🇬🇧UK

Prescription only medicine (POM), regulated by MHRA.

Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.

8 Research Publications

Safety, efficacy, and pharmacokinetics of oral testosterone undecanoate in males with hypogonadism.

Human

Andrology · 2025

Researchers observed that oral testosterone undecanoate effectively increased testosterone levels in men with low testosterone, with 87% of participants achieving normal levels. Additionally, this treatment improved mental health and sexual function compared to a topical testosterone gel, with no serious safety concerns reported.

87% of men on oral testosterone undecanoate reached normal testosterone levels.
Improvements in mental health and sexual function were noted compared to topical gel.
Safety profiles were similar for both oral and topical testosterone treatments.

PubMed

Micropenis.

Review

Indian journal of pediatrics · 2023

Researchers observed that micropenis is defined as an unusually small penis, with specific measurements indicating when it should be evaluated. They found that various hormonal and genetic factors contribute to its development, and treatment often includes hormonal therapy, although surgery is less common and results vary. Long-term studies are needed to assess the effectiveness of treatments on adult penis size.

Micropenis is defined by specific size measurements at birth and after age five.
Hormonal and genetic factors play a significant role in its development.
Treatment typically involves hormonal therapy, with limited surgical options.

PubMed

Efficacy of changing testosterone gel preparations (Androgel or Testim) among suboptimally responsive hypogonadal men.

Human

International journal of impotence research · 2008

Researchers observed that changing testosterone gel brands can significantly improve testosterone levels and reduce symptoms in men who were not responding well to their initial treatment. Specifically, switching from Androgel to Testim led to higher testosterone levels, while switching from Testim to Androgel helped manage side effects.

20% of men on testosterone gel therapy switched brands due to poor response.
Switching from Androgel to Testim increased testosterone levels significantly.
Switching from Testim to Androgel helped reduce unwanted side effects.

PubMed

Prospective study of topical testosterone gel (AndroGel) versus intramuscular testosterone in testosterone-deficient HIV-infected men.

Human

HIV clinical trials · 2007

Researchers found that daily use of a topical testosterone gel (AndroGel) resulted in more stable testosterone levels and improved quality of life compared to intramuscular testosterone injections in HIV-infected men with low testosterone. The gel led to fewer fluctuations in testosterone levels and enhanced physical and emotional well-being.

Topical testosterone gel provided more stable testosterone levels than intramuscular injections.
Participants reported better physical and emotional well-being with the gel.
No significant changes in body composition were observed between the two treatments.

PubMed

Testim 1% testosterone gel for the treatment of male hypogonadism.

Review

Clinical therapeutics · 2005

Researchers found that Testim 1% testosterone gel effectively raised testosterone levels in men with hypogonadism and improved sexual desire and motivation. They observed significant increases in lean body mass and bone density, with fewer side effects compared to testosterone patches.

Testim gel significantly increased total and free testosterone levels.
Men reported improved sexual desire and motivation after using Testim.
Testim caused fewer skin reactions compared to testosterone patches.

PubMed

Testosterone therapy--what, when and to whom?

Review

The aging male : the official journal of the International Society for the Study of the Aging Male · 2004

Researchers observed that testosterone therapy is beneficial for men with low testosterone levels, especially those experiencing symptoms related to aging. New treatment options, such as a hydroalcoholic gel and intramuscular injections, offer effective alternatives with fewer side effects compared to traditional methods.

15-25% of men over 50 may have low testosterone levels.
New testosterone gel shows high patient satisfaction and fewer side effects.
Intramuscular testosterone undecanoate requires fewer injections and maintains stable hormone levels.

PubMed

Testosterone therapy in erectile dysfunction.

Review

The aging male : the official journal of the International Society for the Study of the Aging Male · 2004

Researchers observed that testosterone therapy can enhance the effectiveness of sildenafil in men with erectile dysfunction who have low testosterone levels. A study showed that combining testosterone gel with sildenafil improved erectile responses compared to sildenafil alone. This suggests that men who do not respond to standard treatments may benefit from screening for low testosterone levels.

Testosterone is important for erectile function and nitric oxide production.
Combining testosterone gel with sildenafil improved erectile response in men with low testosterone.
Screening for low testosterone is recommended for men who do not respond to standard erectile dysfunction treatments.

PubMed

Evaluation of the pharmacokinetic profiles of the new testosterone topical gel formulation, Testim, compared to AndroGel.

Human

Biopharmaceutics & drug disposition · 2003

Researchers found that Testim, a new testosterone topical gel, leads to higher levels of testosterone in the body compared to AndroGel, an existing product. Specifically, Testim showed greater increases in total testosterone, dihydrotestosterone, and free testosterone after application. This suggests that Testim may be more effective in delivering testosterone than AndroGel.

Testim resulted in 30% higher total testosterone levels than AndroGel.
Testim showed 19% higher dihydrotestosterone levels compared to AndroGel.
Testim provided 38% higher free testosterone levels than AndroGel.

PubMed

Track your hormone research in PepStack

Log cycles, set reminders and visualize serum levels.

Download on theApp Store Get it onGoogle Play

This page is for informational and research purposes only. All information is based on published scientific literature. Nothing on this page constitutes medical advice or replaces consultation with a qualified healthcare professional.