Men in the Northern hemisphere may feel their libido waning as the days grow darker in winter, but researchers may have just found a solution. A new study suggests light therapy can help boost testosterone levels in men, in turn boosting their sexual satisfaction.
The study comes from Professor Andrea Fagiolini and other researchers at the University of Siena in Italy. The scientists presented their findings at the European College of Neuropsychopharmacology (ECNP) conference in Vienna, Austria September 19th. After other researchers had noticed sexual interest waxes and wanes along with the seasons, the study authors thought that light levels may play a role in sexual desire. They set out to investigate.
For their study, the researchers recruited 38 male patients at the Urology Department of the University of Siena. All the men were diagnosed with hypoactive sexual desire disorder or sexual arousal disorder, which means they had low interest in sex. After evaluating each man’s interest in sex, along with measuring their testosterone levels, the researchers divided the men into two groups. One group participated in treatment with a light box, similar to the light boxes which treat Seasonal Affective Disorder. The other group received similar treatment, but with a light box designed to emit much lower light levels. All study participants received treatment with their light box or modified light box for half an hour a day early in the morning. After two weeks, the researchers again evaluated the men for sexual satisfaction and testosterone levels.
When the researchers compared the two groups of men before and after their treatment, the differences were significant. At the beginning of the study, all participants had an average 2 out of 10 sexual satisfaction score. After treatment with the low-light light box, the control group showed an average score of 2.7 out of 10 for sexual satisfaction, a slight increase. However, after treatment with their functioning light box, the treated men averaged a score of 6.3 out of 10 for sexual satisfaction. This means that two weeks of light exposure for half an hour a day helped these men more than triple their feelings of sexual satisfaction.
Not only did the men treated with light therapy increase their feelings of sexual satisfaction, but they also increased their testosterone levels. At the beginning of the study, the researchers measured testosterone levels at an average of 2.1 to 2.3 ng/ml. After two weeks, the control group with the low-light light box remained at about 2.3 ng/ml average testosterone level. However, the group who received light therapy for two weeks increased their testosterone levels to an average of 3.6 ng/ml, a more than 50 percent increase. While it is not surprising that the men with higher testosterone levels experienced greater sexual satisfaction, what is significant is that light therapy helped men improve their testosterone levels.
The researchers did not find this entirely surprising. In the Northern hemisphere, men’s testosterone production tends to decline from November to April during the short days of winter, rising steadily through the spring and summer as the days get longer and sunnier. Testosterone levels tend to peak in October in the Northern hemisphere. The testosterone levels tend to drive sexual activity, so that June has the highest rate of conception.
Scientists believe light therapy works for treating seasonal affective disorder and sexual dysfunction by mimicking sunlight, tricking the body into thinking it is summer. In this study in particular, the study authors believe light therapy may inhibit the pineal gland in the brain, which may have a connection to light receptors. With a reduction in the pineal gland’s activity, the body may produce more testosterone. However, there could be other explanations for why light therapy boosts testosterone, and more research would need to determine exactly how it works.
Although the light therapy shows promise for treating low testosterone and sexual dysfunction, the study authors warn it is too early to recommend this as a treatment since the study only involved 38 patients. More, larger studies would need to confirm if the therapy works. Even if the therapy does help most patients, some will still have to be cautious about light therapy, such as patients taking prescription drugs that affect light sensitivity or those with an eye condition. That said, for most patients the light therapy would be non-invasive with few side effects, making it an appealing alternative to prescription drugs.
Light therapy is only one potential treatment for sexual dysfunction, along with testosterone injections, antidepressants, and other drugs. Treatment will depend on the underlying cause, and light therapy may not be appropriate in all cases. Testosterone injections, for example, may treat low libido due to low testosterone, while erectile dysfunction drugs like Viagra or Cialis may help a man achieve and maintain an erection, but cannot help treat an underlying cause like low sexual desire. Light therapy may not help a problem such as erectile dysfunction if it is not caused by low libido.
After the age of 40, up to 25% of men may report problems with low sexual desire, according to previous studies. Low libido may be caused by psychological issues like depression, stress, and relationship problems, or physical issues like alcohol or drug use, too much or too little exercise, side effects of prescription drugs, or low testosterone. Low testosterone may be caused by natural loss with aging, seasonal variation, illness, a problem with the pituitary gland or hypothalamus, or other factors. Depending on the cause, doctors may treat low libido with testosterone replacement therapy, lifestyle intervention, or psychological counseling.