In its active form, vitamin D works as a steroid hormone in the body. Research suggests that it’s crucial for male sexual function.(1)
There’s been a lot of research analyzing the link between vitamin D and testosterone production, and the findings are really interesting. But since tracking down all this research can be time-consuming, I thought I’d put together a brief article highlighting what we know so far.
So what exactly does vitamin D have to do with testosterone, and is it really a good way to increase testosterone? Mainly, vitamin D inhibits a process known as aromatization, where testosterone is changed into estrogen.
There’s also data showing that vitamin D may enhance cell receptor sensitivity in the testicles where testosterone is produced.
As it turns out, increasing vitamin D levels may increase testosterone and improve other related areas of health, including sperm quality.
A study in 2010 indicated that men with sufficient vitamin D levels had significantly higher levels of free testosterone and free androgen index (FAI), and lower levels of sex hormone binding globulin (SHBG) when compared to men with insufficient or deficient vitamin D.
Interestingly, this study also showed that testosterone levels follow a seasonal pattern, peaking in August and being at lowest levels in March.(2)
In another one-year study, researchers divided 65 men into 2 groups. One group took a daily dose of 3,300 IU of vitamin D.
That group’s vitamin D levels doubled, and their testosterone levels increased by approximately 20%.(3)
Another study in 2008 showed that the risk of falls in the elderly was reduced more in individuals with increased testosterone, vitamin D, and calcium, compared to only elevated testosterone levels. This suggests that a synergistic relationship exists between testosterone and vitamin D.(4)
Another study conducted in 2011 demonstrated that men who supplemented vitamin D had significant increases in total testosterone, bioactive testosterone, and free testosterone when compared to baseline. However, those who did not supplement with vitamin D did not show significant increases in any of those levels.(5)
Many of the studies conducted were looking at people who already had a vitamin D deficiency for one reason or another. Like most vitamins and health supplements, there is almost certainly a point of diminishing returns at which the benefits subside.
How Much Vitamin D Do You Need?
According to the National Institute of Health, 600 IU’s per day is recommended for those over the age of 18, and for those over the age of 70, 800 IU’s per day. If you are in a high-risk deficiency group you may need to take more – one of the studies mentioned above had the participants taking 3,000 IU’s per day.
Those who may be at risk of being vitamin D deficient include those suffering from chronic disease (such as kidney disease). People with limited exposure to sunlight may have low levels of vitamin D, as well as those who live in colder climates.
Basically, the farther you live from the equator, the greater your risk for vitamin D deficiency.
Sources of Vitamin D
Vitamin D is a fat-soluble vitamin that your body produces upon exposure to sunlight.
The best (and cheapest) source of vitamin D is exposure to sunlight. 30 minutes a day between the hours of 10 AM and 2 PM is enough for most.
Besides sunlight, there’s plenty of dietary sources to choose from, including fatty fish (such as salmon, tuna, and mackerel), liver, eggs, cheese, and foods that have vitamin D added, such as milk, orange juice, and breakfast cereals.
Supplements are probably the easiest way to ensure you’re getting plenty of vitamin D. Fish oil is not only packed with vitamin D, but also rich in omega-3 fatty acids. And many good multivitamins for men and workout supplements will also contain plenty of vitamin D.
As far as vitamin D’s impact on testosterone, it’s pretty clear that men who are deficient in vitamin D show an increase in testosterone after they begin supplementation. Whether or not the same results occur in men with already normal levels of vitamin D is unclear at this point.
Fortunately, taking vitamin D supplements causes very few, if any, side effects, especially if taking the recommended daily allowance. Because of the important benefits, all men should include adequate amounts of vitamin D as part of their health supplement regimen.