What makes a man, a man? That’s a complicated question. But from a purely biological perspective, the answer is simple: the hormone called testosterone. Men generally produce far more testosterone than women. It’s responsible for many of the qualities we consider “manly”—deeper voices, hairy chests, muscular frames, etc.
Unfortunately, around age 30, testosterone levels start to drop. This is normal, but it can bring a lot of challenges to a man’s life—things like reduced sexual function, decreased energy, a decline in muscle, and an increase in fat. To make matters worse, testosterone is adversely affected by a host of common challenges that affect nearly all men today, such as poor nutrition, stress, and lack of sleep—and that’s just to name a few. These factors combine to produce dramatically decreased testosterone levels for a lot of men.
Doctors often suggest supplementation or medication to help with the difficulties of low testosterone or to treat testosterone abnormalities. But these traditional solutions may lead to unwanted side effects. That’s why so many people are after a more natural option. And it turns out that red and near infrared light therapy shows promise for increasing testosterone in a safe and efficacious way.
Studies Support the Use of Red and Near-Infrared Light Therapy for Boosting Testosterone
To the surprise of most, exposing the torso or the testes to light has been shown to increase testosterone in men. In fact, studies related to the effect of light on the testes actually go back to the 1930s. In an initial study in 1939, it was found that men’s testosterone levels went up by 120 percent when the participants’ chests were exposed to ultraviolet (UV) light. Even more impressive, these testosterone levels went up by 200 percent with UV exposure to the genital area. Even though most people want to limit their exposure to UV light because of its potential to cause cancer, this nearly 100-year-old study demonstrated the positive impact that natural light can have on testosterone production.
Today, new studies are demonstrating positive results from light therapy on testosterone levels. A 2013 study in Biomedical Research examined the effect of light therapy on testosterone production in rats. This study found that light therapy at 670 nanometers (nm) increased the serum testosterone levels, with no noted side effects. Due to their findings, the researchers stated that red light therapy could potentially work as an alternative treatment method to traditional testosterone treatments.
The positive results hold up in human trials as well. A 2016 randomized, placebo-controlled study conducted by the University of Siena evaluated men with a low sexual desire. It found that using light therapy generated a testosterone increase that resulted in better sexual satisfaction. Although this was a relatively small pilot study, it suggests light therapy can indeed lead to enhanced testosterone levels.
How Does Red and Near Infrared Light Therapy Improve Testosterone Levels
In other posts, we explained how the human body absorbs red and near infrared light, which encourages increased cellular chemical energy transportation—otherwise known as adenosine triphosphate (ATP). Just as improved function can be observed throughout various bodily processes, our friend Dr. Olli Sovijarvi—author of the Biohacker's Handbook—has stated that red and near infrared light wavelengths encourage the production of ATP in the Leydig cells that produce testosterone, enhancing their energy production and helping increase amounts of the hormone.
Other theories exist about how light therapy boosts testosterone levels. Dr. Sovijarvi has also described a theory that light wavelengths stimulate photoreceptive proteins in the testes, resulting in higher testosterone production. In addition, researchers in the aforementioned 2016 University of Siena study suggested that the light therapy used could have blocked the brain’s pineal gland, which resulted in the creation of more testosterone.
In a 2013 study in the Nepal Medical College Journal, researchers observed that the follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are connected to the production of testosterone, were elevated in rats subjected to light for 70 days. The researchers suggested that these increased hormones may have encouraged elevated testosterone production.
While there are multiple theories in terms of the mechanism of action, it’s pretty clear that light therapy does indeed lead to increased testosterone production!
Which Wavelengths of Light are Best for Increasing Testosterone?
Some people have reported potentially negative effects to testes when using light therapy. However, any detrimental ramifications are related to longer wavelengths that produce more heat, which isn't optimal for boosting testicular function. In fact, wavelengths above 1,000 nm produce much more radiant heat because water in the body absorbs more of these frequencies. This isn't an issue with red or near infrared wavelengths, which generate very little heat and have been proven in multiple clinical studies to boost sperm health.[3,6,7]
Conclusion: Red and Near Infrared Light Therapy Shows Promising Results for Increasing Testosterone Levels
Numerous studies have supported the idea that light therapy can increase levels of testosterone. In addition, red and near infrared light is considered safe for use–even when directed on the testicles. Nonetheless, a general rule of thumb is to avoid too much heat, which could have a detrimental effect on the testosterone-producing Leydig cells.
That’s why it’s imperative to use an LED light therapy device that delivers optimal power without producing heat. Efficient delivery of the right wavelengths with virtually no heat–that’s the ideal combination, and it’s a critical design element that we’ve optimized in the Joovv Light. Check it out when you get a chance–we think you’ll be impressed!
 The Healthline Editorial Team, Gotter A and Rogers G, MD. Low Testosterone in Men. Healthline. Jul 2016.
 Myerson, A. Influence of ultraviolet radiation on excretion of sex hormones in the male. Endocrinology. 1939;25:7-12.
 Ahn JC, Kim YH and Rhee CK. The effects of low level laser therapy (LLLT) on the testis in elevating serum testosterone level in rats. Biomedical Research. 2013; 24(1):28-32.
 Fagiolini A et al. Lack of interest in sex successfully treated by exposure to bright light. European College of Neuropsychopharmacology. Sept 2016.
 Sovijarvi O. Dr. Olli Sovijarvi on Increasing Testosterone by Shining Light on Your Testicles. Biohacker Summit Blog. Oct 2016.
 Biswas NM, Biswas R, et al. Effect of continuous light on spermatogenesis and testicular steroidogenesis in rats: Possible involvement of alpha 2u-globulin. Nepal Med Coll J. 2013;15(1):62-64.
 Salman Yazdi, R., Bakhshi, S., Jannat Alipoor, F. et al. Effect of 830-nm diode laser irradiation on human sperm motility. Lasers Med Sci. (2014) 29: 97.