Transdermal Testosterone

Transdermal Testosterone is a form of Testosterone Replacement Therapy (TRT) where the hormone is absorbed through the skin, bypassing the digestive system and liver metabolism.

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Detailed Explanation and Different Names

This delivery method allows for a relatively steady level of testosterone in the bloodstream, often mimicking the body's natural circadian rhythm if applied daily in the morning.

Different Names (Common Brand Names):

• Gels:

  • AndroGel (Testosterone gel 1% and 1.62%)

  • Testim (Testosterone gel 1%)

  • Vogelxo (Testosterone gel)

  • Fortesta (Testosterone gel, applied to the thighs)

• Solutions/Roll-ons:

  • Axiron (Testosterone topical solution, applied to the armpit)

• Patches:

  • Androderm (Testosterone transdermal patch)

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Side Effects and Benefits

Transdermal testosterone, like all forms of TRT, is primarily used to treat hypogonadism (low testosterone levels) in adult men.

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Pros and Cons

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Dosage and Frequency

The optimal dose is highly individualized and is adjusted based on a patient's symptoms and blood test results to achieve testosterone levels in the normal range (e.g., 300 to 1000 ng/dL).

• Frequency: Once daily, usually in the morning.

• Typical Starting Dosages:

  • Gels/Solutions (e.g., AndroGel 1.62%): Often starting at 40.5 mg of testosterone daily (e.g., 2 pump actuations or 1 packet).

  • Patches (e.g., Androderm): Typically a 4 mg/day patch applied nightly.

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Half-Life and Detection Time

• Serum T Levels: Following discontinuation, serum testosterone levels typically return to pretreatment levels within 5 days for transdermal gels/solutions.

• Drug Testing (Detection): For performance-enhancing drug testing, detection is based on the ratio of testosterone to its metabolites (like epitestosterone) in urine. Because testosterone is an endogenous (naturally produced) substance, it is hard to give an exact detection window. Detection of exogenous (external) testosterone can last for weeks to months, depending on the sensitivity of the test and the specific formulation used, as metabolites can linger.

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Sterogenic, Progestronic, Prolactin, and Anabolic/Androgenic Ratio

Sterogenic and Progestronic Effects

Testosterone itself is primarily an androgenic and anabolic steroid.

• Sterogenic (Estrogenic) Effects: Testosterone is converted into the potent estrogen Estradiol (E2​) by the aromatase enzyme. This conversion is responsible for some beneficial effects (like bone health) but also for side effects like gynecomastia and fluid retention. Transdermal administration, compared to high-dose injections, generally leads to more stable E2​ levels.

• Progestronic Effects: Testosterone and its derivatives typically have negligible or no direct progestogenic activity.

Prolactin Affects

• Testosterone replacement therapy generally does not significantly change prolactin levels in men. While very high doses of certain anabolic-androgenic steroids can potentially influence prolactin, therapeutic transdermal TRT is not typically associated with hyperprolactinemia (elevated prolactin).

Anabolic Androgenic Ratio

The ratio of a steroid's anabolic (muscle-building) effects to its androgenic (masculinizing/secondary sex characteristics) effects is used to characterize its activity.

• Testosterone is considered the baseline and has an Anabolic:Androgenic Ratio of 100:100 (or simply 1:1).