Male hypogonadism, or Testosterone Deficiency (TD), involves decreased testicular function, leading to low androgen levels and impaired sperm production. This condition can negatively impact quality of life and increase cardiovascular risks. The adult hypogonadism frequently occurs over 40 in men, and it is characterized by persistent symptoms alongside low testosterone levels, typically below 300 ng/dL. Supplementation with  testosterone as a replacement therapy (TRT) is  hormonal enhancement found to be effective, however the delivery methods vary, each with specific advantages and drawbacks. The TRT has potentially life-changing effects, patients feel improved quality of life in several aspects: more energy and muscular strength, increased libido, improved mood, etc. as the most ferquent patients reported outcome.

Oral TRT, particularly testosterone undecanoate (TU), offers notable convenience. TU is absorbed via the lymphatic system, bypassing first-pass hepatic metabolism, making it a promising agent for TRT. Its absorption, however, is influenced by dietary factors, such as lipid intake, thus the high-fat consumption promoting lymphatic absorption. Pharmaceutical technology to address this dependency, newly developed TU formulations incorporate special self-emulsifying systems that enhance lymphatic absorption regardless of food fat content. This lymphatic absorption allows for stable testosterone levels, positioning TU as a viable also for an oral treatment option.