Most of the body’s testosterone supply is manufactured by the skin, stimulated by exposure to sunlight, with the remaining amount supplied by a man’s diet.

Low testosterone levels can wreck havoc with a man’s libido, in addition to making his energy levels crash. Proper testosterone levels also help a man maintain muscle strength and bone density, two characteristics essential to enjoyable lovemaking.

Research findings recently reported in the Clinical Endocrinology Journal indicate that a study of 2,299 men found that men who had sufficient vitamin D levels thanks to sunlight exposure had more male sex hormones than men with limited sunlight exposure.

Researchers at the Medical University of Graz, Austria, report that a measurement of 30 nonograms of Vitamin D per millilitre of blood benefited men with corresponding higher testosterone levels. Peak levels of both testosterone and vitamin D appeared in August, with the lowest levels found in March. Continued studies are seeking to determine if vitamin D supplements will have the same boost on male testosterone levels as sunlight exposure.

The Sunlight Research Forum in The Netherlands concurred with the recent study, adding “Men who ensure that their body is at least sufficiently supplied with vitamin D are doing good for their testosterone levels and their libido among other things.”

Although testosterone replacement therapy has been a traditional course of action for men with low levels of testosterone, the new findings provide healthy men with a natural avenue for increasing their vitamin D levels, along with their testosterone and libido, simply by spending more time in fresh air and sunlight.

Cancer researchers are balancing the good news about sunlight exposure and libido, cautioning that exposure to the sun must be sensible and moderate to prevent cancer.

Notes Jessica Harris of Cancer Research UK: “Enjoying the sun safely without burning should help people strike a balance between making enough vitamin D and avooiding a higher risk of skin cancer.”

Harris also recommended that increased vitamin D levels can be achieved by consuming more seafood with omega-3 oils such as mackerel, salmon and trout.

The study found that male cancer survivors struggling with a testosterone deficiency due to chemotherapy or radiation have lower energy levels, decreased sexual function, and a lower quality of life.

Interestingly enough, the young survivors seem to cope well with the issues. Most did not appear to suffer psychologically or have a low self-esteem, nor did it impair their sexual relationships. This evidence leads scientists to suggest the idea that having survived cancer may have impacted the relationship more powerfully than the lack of sexual performance.

Richard J.M. Ross, MD, and his colleagues have determined that impairment of energy, sexual functions, and quality of life are even worse in cancer survivors with hypogonadism, or low testosterone levels. They suggest future studies being done to see if hormone replacement can help the men in these situations.

His study involved comparing 176 cancer survivors to 213 young men that had never had cancer. All of the participants were between 25 and 45 years old and the cancer survivors had been treated for non hormone-dependent cancers. The survivors had also undergone chemotherapy and/or radiotherapy as part of their cancer treatment. All participants had their testosterone levels measured and each completed three quality of life questionnaires: the Short-Form Health Survey, Aging Male Scale, and the Functional Assessment of Chronic Illness Therapy-Fatigue, as well as measures to test their self-esteem, fatigue levels and sexual functions.

Findings indicated that compared to those without cancer, the cancer survivors reported impaired quality of life and more fatigue in most portions of the surveys. Also, the cancer survivors with the lowest testosterone levels reported a worse quality of life and lower self-esteem, fatigue, and sexual function than those with higher levels of testosterone present in their bloodstream. The researchers also found that when testosterone levels were higher, the scores from the Physical Component Summary, or PCS from the Short-Form Health Survey, were also higher.

The study, which was funded by the Weston Park Hospital Cancer Charity along with help from the Laura Crane Trust, indicates hormone replacement therapy may help increase the quality of life for male cancer survivors, especially those that are suffering from hypogonadism. Additional research may soon follow.

Testosterone’s effects can be felt above the belt, too. A 2008 Archives of General Psychiatry study found that older men with the lowest levels of free testosterone were at a higher risk for depression than men with the highest levels. Researchers haven’t pinpointed the link, but other studies have shown that waning testosterone levels may lead to increased fat mass, irritability, and a lower sex drive.

Testosterone: Not Just for Libido

Testosterone is the most important metabolic hormone for men and many do not realize that it affects much more than just libido. Findings reported in the Wall Street Journal in December 2009 reveal that men with low testosterone tend to be tired and grumpy, have less energy, less strength, in addition to less interest in sex than they used to have. They also have a high risk of memory problems, obesity, high blood pressure, high cholesterol and are more likely to have cardiovascular disease.

You can not maintain or build muscle mass without having free, unbound testosterone in your body.