Red Light Therapy (RLT), also known as photobiomodulation is being used in thousands of clinical studies to treat everything from skin conditions to neurodegenerative diseases. It works.
An Italian study in 2016 shows that exposure to bright light increases testosterone levels. A group of 38 men who had a diagnosis of hypoactive sexual desire disorder (low interest in sex). These men were divided into two groups. One group received one-half hour of bright light treatment in the morning. The placebo group received a much less intense light treatment for a half hour. The light device used is similar to the ones that treats Seasonal Affective Disorder (SAD).
After two weeks the untreated group did not report any difference in their sexual desire. The treated group reported a 3-fold increase in sexual satisfaction. The free testosterone level in the placebo group remained unchanged. While the free testosterone in the treated group increased by more than 50%, from 2.1 ng/ml to 3.6 ng/ml. (study)
The ability of sunlight to improve testosterone levels has been known for a long time. (source) How sunlight improves testosterone levels is by stimulating the body’s vitamin D production. Increased vitamin D, especially those you are deficient in vitamin D, raises testosterone levels. This, partially explains the higher seasonal pregnancy rate in the summer (study).
The ability of UV light to stimulate testosterone in men has been known since a 1939 clinical study. Dr. Myerson, exposured the chest area of men to UV light over the course of five days. The results of the exposure boosted testosterone levels incrementally over the five day ending on the fifth day with a 120% increase over baseline.
Dr. Myerson then stopped the UV exposure and watch the testosterone levels incrementally decrease and returned to baseline after a period of 8 days.
The next experiment followed the same course of treatment, but exposed the male genitals with UV light instead of the chest. Again, over the course of a five day treatment, testosterone levels incrementally increased and by the fifth day there was a 200% increase over baseline. Exposure was stopped and again testosterone levels dropped back to baseline over a 8 day period (study), (study).
Red Light Therapy
In a rat study, 670nm light caused an increase in serum testosterone (study).
There is anecdotal information from men who are using RLT to increase testosterone. One of the better articles is by Ben Greenfield for Mens Health magazine.
Mike Matzel used red light therapy for 90 days for 12–15 minutes a day and doubled his testosterone from 501 ng/dL to 902 ng/dL. More impressive than the total testosterone is that his free testosterone, also doubled from 8.2 pg/mL to 15.4 pg/mL.
The specification of the RLT, such as wattage of light and distance was not provided. The full interview with Mike is available on YouTube.
Dr. Michael Hamblin
Dr. Michael Hamblin is the foremost authority on RLT has stated in a interview when asked if RLT increases testosterone in men said that he doesn’t see why not. Which is to say, that since RLT increases a cells ability to do what a cell is designed to do, it is probable to assume RLT will increase testosterone. But in the absence of studies, we cannot say for sure. (interview)
Where the heck are the studies?
This question has baffled me for years. This study would be relatively simple to perform, yet not one clinical study has been published.
Light can have a positive impact on men’s testosterone level. It would stand to reason RLT would increase the ATP production in a man’s leydig cells that would boost testosterone levels.
The bright light, sunlight and RLT are relatively safe. I would be cautious against using a UV light or tanning light as it has the potential to increase skin cancer.
Recent anecdotal information has shown a doubling of total testosterone and free testosterone in three months using RLT.