testosterone undecanoate + d-alpha tocopherol

Testosterone undecanoate + d-alpha tocopherol is a **combination drug** composed of testosterone undecanoate, an androgen and anabolic steroid used for testosterone replacement therapy in adult males with primary or hypogonadotropic hypogonadism, and d-alpha tocopherol, a natural form of vitamin E often used as an antioxidant. **Testosterone undecanoate** acts as a prodrug of testosterone, which binds to the androgen receptor to regulate development and maintenance of male secondary sex characteristics and other physiological functions. **D-alpha tocopherol** provides antioxidant activity, protecting cells from oxidative stress, and stabilizes oil-based injection formulations. This combination may be used in some intramuscular injectable formulations to enhance stability or tolerability, but it is not a major marketed product under a unique brand name.