RT Journal Article SR Electronic T1 ▾ Testosterone undecanoate – oral therapy for male hypogonadism JF Drug and Therapeutics Bulletin JO Drug Ther Bull FD BMJ Publishing Group Ltd SP 7 OP 8 DO 10.1136/dtb.23.2.7 VO 23 IS 2 YR 1985 UL http://dtb.bmj.com/content/23/2/7.abstract AB In men with sexual dysfunction due to hypogonadism, plasma testosterone is by definition low; testosterone replacement therapy may help to overcome impotence and loss of libido, but not infertility. Oral administration of the natural hormone is inefficient because testosterone, like some other natural steroids, is rapidly inactivated in the gut wall and liver. Sublingual administration allows direct absorption into the systemic circulation, but frequent dosing is needed. Testosterone is therefore usually given in the UK as an ester by intramuscular injection every 2 – 4 weeks, or by surgical insertion of an implant every 3 – 6 months with risk of extrusion1, infection or haematoma formation.2 An oral preparation which raised plasma testosterone predictably when given by mouth would therefore represent a significant therapeutic advance. This is what Restandol (Organon) - testosterone undecanoate dissolved in oleic acid - is claimed to offer.