Testosterone replacement therapy (TRT) is a medical treatment used to address low testosterone levels, a condition known as hypogonadism. Among the various methods of delivery, the testosterone pellet system offers a unique approach that provides a consistent and long-acting dose of the hormone. This method involves the subcutaneous implantation of small, solid pellets that slowly release testosterone into the body. Pellets are a convenient option that avoids the need for daily creams or patches, or the peaks and troughs often associated with injections.
Physical Characteristics and Composition
The physical appearance of a testosterone pellet is often compared to a grain of rice or a Tic Tac. These small implants are typically cylindrical in shape, measuring approximately 3 millimeters (mm) in diameter and 9 mm in length. They are usually white or off-white and consist of crystalline testosterone that has been compressed into a solid form.
The primary active ingredient is testosterone, with each pellet commonly containing about 75 milligrams (mg) of the hormone. To maintain their solid structure and regulate the release rate, pellets are mixed with inactive ingredients, often including a binding agent like stearic acid and polyvinylpyrrolidone. The pellet’s composition is designed to be bio-identical, meaning the chemical structure of the testosterone matches the hormone naturally produced by the human body. Once implanted, this solid matrix allows for a sustained and gradual release of the hormone directly into the bloodstream.
The Insertion Procedure
Testosterone pellets are implanted during a quick, minimally invasive in-office procedure. The implantation site is usually in an area with subcutaneous fat, most commonly the upper outer buttock, hip, or lower abdominal region. The area is first cleaned and sterilized before a local anesthetic is injected to completely numb the site, minimizing any discomfort during the process.
A small incision, generally about 3 to 5 mm in length, is then made in the skin. A specialized medical instrument called a trocar is inserted through this incision into the fatty layer just beneath the skin. The prescribed number of pellets—which can be anywhere from a few to a dozen, depending on the individual’s required dose—are then placed into the trocar and pushed into the subcutaneous tissue. Once the pellets are correctly positioned, the trocar is removed, and the small incision is closed.
Mechanism of Action and Longevity
Once implanted beneath the skin, the testosterone pellet functions as a subcutaneous depot. The mechanism relies on the pellet’s crystalline structure being slowly broken down by the body through dissolution and absorption, releasing the hormone into the surrounding tissue and blood circulation. The release rate is steady and continuous, which helps maintain stable hormone levels and avoids the peaks and troughs seen with other methods like injections or daily applications.
The longevity of a single pellet insertion typically ranges from three to six months, with most individuals requiring re-implantation around the four-month mark to maintain optimal hormone levels. The rate at which the pellet dissolves and the duration of its effect are individualized. The pellets are designed to fully dissolve and biodegrade, meaning they do not need to be surgically removed at the end of their life cycle.