Transdermal testosterone delivery: testosterone patch and gel.

Testosterone replacement treatment is usually life-long. Fortunately, testosterone administration is relatively safe and until the age of 50 years few side effects are noted with normal doses of testosterone. After the age of 50 years when prostate disease becomes more prevalent, shorter-acting testosterone preparations, allowing a fast reduction of circulating testosterone levels, may be an advantage. Testosterone has an impact on sexual and non-sexual behaviour and short-acting testosterone preparations may be better suited for the initiation of long-term administration allowing the monitoring of behavioural effects. Testosterone can be delivered to the circulation through the intact skin, both genital and non-genital. Transdermal administration delivers testosterone at a controlled rate into the systemic circulation, avoiding hepatic first pass and reproducing the diurnal rhythm of testosterone secretion and without the peak and trough levels observed with the use of the traditional long-acting testosterone injections. In conclusion, both the testosterone patch and testosterone gel are valuable contributions to androgen replacement treatment meeting the requirements specified for testosterone replacement treatment.