Natural testosterone has been found to increase when circulating levels of vitamin D are increased, according to a study by researchers at the Medical University of Graz, Austria. The sun has been found to naturally increase testosterone levels of men, protecting both his overall health and increasing his sexual desire. In fact, according to Adi Brand of the Netherlands’ Research Forum of Sunlight, “Men who say that your body is at least sufficiently supplied with vitamin D are doing good for your testosterone levels and libido, among other things.”

From age 30 onwards, men experience a decline in sex hormone levels of about 1.5 percent annually. The decreasing level of testosterone is responsible for the reduction of bone density and muscle mass, insulin resistance, and depression. Increasing a man’s natural testosterone level by getting enough vitamin D will help him to maintain a healthy bone density, muscle mass and protect him from developing diabetes.

Researchers at the Netherlands’ Research Forum of Sunlight tested the vitamin D and testosterone levels of 2299 men over the course of several months. Their findings reveal that levels of vitamin D and testosterone concurrently peaked in the summer and fell during the winter. They also found during their research that men who had at least 30 nanograms of vitamin D in each milliliter of blood had the highest levels of circulating testosterone.

Vitamin D and in turn, natural testosterone are produced by the body when exposed to direct sunlight. The scientists recommend that people with lighter skin take in at least 15 minutes of direct sunlight per day in the face and hands, while darker-skinned people may need up to 45 minutes of direct sunlight in order to obtain the same benefits.

Sunscreen does prevent ultraviolet radiation from reaching your skin, which is necessary for the body to synthesize vitamin D. It is a balance between taking enough sun in to boost natural testosterone levels while avoiding the increased risk of skin cancer. The body can synthesize all the vitamin D you need at a fraction of the time it takes to sunburn.

Men who have low levels of natural testosterone are at an 88% increased risk of early death from compromised health due to issues with depression, loss of motivation, a lower sex drive and lower muscle mass. A very easy way to maintain a healthy testosterone level is through adequate absorption of Vitamin D through sunlight or supplementation.