Testosterone skin gel could be a safe and effective treatment for men with ADHD, with Norwegian doctors reporting a marked improvement in symptoms in a new case series.

In three adult patients, testosterone therapy was initiated after discontinuing centrally acting stimulants due to side effects including loss of libido and overactive bladder.

The reported benefits — including reduced impulsivity, inattention, insomnia and seasonal depressive symptoms — were apparent within days of starting the hormone treatment, the authors report.

“The effect has now continued for 4.5-5 years at the same doses: 10-60mg testosterone/day, administered as a skin gel,” they wrote in the Journal of Medical Case Reports.