The objective of the study was to evaluate the adhesiveness of a new thin, transparent and comfortable testosterone-in-adhesive matrix patch, Testopatch®, after extreme conditions. The study was a single-centre, open-label with randomization of sites (upper arms, lower back, thighs) and sides (left, right) of two 45 cm2 patches, in 24 healthy subjects. Patches were symmetrically applied on one of the three sites. One patch was removed after 2.0 h, under resting conditions and the other patch was removed at 3.5 h, after extreme conditions (physical exercise, sauna, whirl bath). Adhesiveness was assessed of the area stuck and the measure of the forces necessary for patch removal using a Peel Patch Tester™. Local safety was assessed at 2.0 and 3.5 h. After physical exercise and after sauna, patch adhesiveness was excellent (95%) when applied on the thigh and very good (90%) on the upper arm. Forces of patch removal were significantly lower at 3.5 h than 2.0 h, and at the lower back compared to the other application sites. There were no adverse effects. Slight erythema was observed that was considered to be clinically insignificant. Testopatch® was safe and displayed adhesiveness, compatible with physical activities.