Undriol (Testosterone Undecanoate) 40 mg capsule – 1 BOX containing 60 capsules. Undriol is a man-made drug for hormone replacement treatement. Your body turns testosterone undecanoate into testosterone. Testosterone is a natural male hormone known as an androgen which controls normal sexual development in men, similar to the a naturally occuring steroid testosterone. Undriol is used in testosterone replacement therapy for male sexual problems such as: impotence caused by hormonal disorders, after castration or a similar problem called eunuchoidism, decreased sex drive and decreased mental and physical activityl, infertility caused by low sperm count, bone loss caused by low hormone levels.