Men exposed to bright light therapy can receive a testosterone level boost that can lead to greater sexual satisfaction then those with a lower sex drive, according to a study presented by University of Siena in Italy at ECNP conference in Vienna.

Low sexual desires affects a large number of men after the age of 40, with research finding up to 25% of men have issues, depending on age and other factors. Previous scientific findings noted sexual interest can be affected by seasonal changes, leading to the idea that levels of ambient light contributes to sexual desires.

Professor Andrea Figiolini from University of Siena in Italy tested subjects sexual and physiological responses to bright light. They found that if men exposed to a light box regularly every morning, similar to those used to counteract Seasonal Affective Disorder (SAD), led to increased testosterone levels and greater levels of sexual satisfaction.

In total 38 men diagnosed with sexual dysfunction symptoms of low libido including sexual arousal disorders or Hypoactive sexual desire disorder (HSDD) from the Urology Department of the University of Siena were evaluated to determine their baseline level of interest in sex and their testosterone levels were measured.

The researchers divided the men into two distinctive groups, one received bright light treatment with a specially adapted light box, while the control group was given a light box with significantly less light output. Both groups received the light therapy early morning, and the treatment lasted only 30 minutes per day for two weeks.

The researchers then retested sexual satisfaction and testosterone levels after the test period.

Professor Fagiolini said: “We found fairly significant differences between those who received the active light treatment, and the controls. Before treatment, both groups averaged a sexual satisfaction score of around 2 out of 10, but after treatment the group exposed to the bright light was scoring sexual satisfaction scores of around 6.3 -- a more than 3-fold increase on the scale we used. In contrast, the control group only showed an average score of around 2.7 after treatment."

Testosterone levels rose in men given the active light treatment, while the average testosterone levels in the control group showed insignificant changes over the course of treatment, which remained around 2.3 ng/ml from start to end of the experiment. Those given active treatment showed an increase from 2.1 ng/ml to 3.6 ng/ml after two weeks.

Men’s testosterone levels fluctuates in the Northern hemisphere, and naturally declines from November to April, and then rises steadily from spring to summer and peaks in October. This affects reproduction rates, where June is the month with highest rate of conception, explained Professor Fagiolini.

The research team explained factors that could lead to the underlying mechanisms, for instance light therapy inhibits the pineal gland in the center of the brain and leads to greater production of testosterone, and there might be other hormonal effects.

However, the research group needs conduct further research before recommending the new light therapy as a new clinical treatment.