Scrotal application and early removal of a new hydroalcoholic testosterone gel is an efficacious alternative for testosterone substitution: Results of a controlled, multicenter trial

Introduction: Hydroalcoholic testosterone (T) gels offer a convenient opportunity for physiological T substitution. We have tested a new 2.5% T gel (TGW, Wolff, Bielefeld, Germany) applied to the scrotum and compared this with i) the dermal (non-scrotal) application of the gel and ii) the T transdermal patch Androderm® 2.5 (Astra Zeneca, Wedel, Germany).

Patients and Methods: In this open, controlled multicenter trial, hypogonadal patients of all ages, with an a.m. T level <10 nmol/l and symptoms of T deficiency, were randomly assigned to one of three parallel groups: scrotal (n=54; dose 1g of TGW/d), dermal (n=56; dose 5g of TGW/d) and patch (n=52; 2 patches/d). TGW was removed by washing 10min after application. Patients were assessed at 4 weekly intervals over a period of 24 weeks and after 4 and 8 weeks a dose adjustment was permitted.

Results: In 96.2%, 69.6% and 76.9% of cases in the scrotal, dermal and patch groups, respectively no dose adjustment was necessary. In the dermal group, the average concentration (Cavg) of T levels was predominantly within the eugonadal range from week 4 onwards and significantly higher compared to the two other groups, whereas DHT levels were significantly higher in both gel groups compared to the patch group. The Cavg of the combined values of T and DHT blood levels remained at the lower limit of the eugonadal range in the scrotal as well as the patch group. PSA levels, prostate volume and haemoglobin levels were within the normal range throughout the study without significant differences between the three groups. Questionnaires related to prostate symptoms, sexual function and mood also revealed no significant differences between the three groups. However, skin reactions were significantly more often observed in the patch group.

Conclusions: TGW provides a good alternative to the patch, independent of whether it is applied to the non-scrotal or, in a very much lower dose, to the scrotal skin. The risk of interpersonal transfer is reduced due to early removal of this gel.