Native testosterone is esterless and pure bioidentical testosterone. Unlike testosterone undecanoate, which is an esterified form of testosterone, native testosterone is not bound to any ester.

Oral TRT with native testosterone is absorbed through the lymphatic system. The lymphatic system is part of the circulatory system and plays a key role in immune function and fat absorption. It transports lymph, a fluid containing white blood cells, throughout the body. The lymphatic system also transfers fat-soluble compounds, including native testosterone, which bypasses the liver initially.

Lymphatic absorption is important because it avoids the first-pass metabolism by the liver. In first-pass metabolism, substances are directly processed by the liver, which can lead to significant degradation and potential hepatotoxicity (liver damage). By being absorbed through the lymphatic system, native testosterone enters the bloodstream before reaching the liver, thus avoiding immediate breakdown and reducing liver strain.

Once native testosterone is in the bloodstream, it is eventually metabolized by the liver, similar to how the body processes naturally produced testosterone. This occurs during the second pass, where substances in the bloodstream are processed by the liver as part of normal circulation. This process is not inherently damaging to the liver.

For optimal lymphatic absorption of oral TRT, it is essential to consume it with a minimum of 30mg of dietary fat provided through whole foods. The presence of fat enhances the absorption process, making the administration of testosterone more effective. Therefore, higher fat intake can further improve the efficacy of the treatment, with studies showing improved efficacy with 40g and even 50g of fat!