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01.02.2010

High vitamin D level = high testosterone level

There's an amazingly simple way for western men to raise their testosterone level. All they have to do is take a supplement containing extra vitamin D. At least, this is what we deduce from an epidemiological study done at the Medical University Graz in Austria, which will soon be published in Clinical Endocrinology.

Vitamin D
Vitamin D is actually a hormone – one that regulates three percent of our genes. Among those genes are a few that are responsible for the production of testosterone in the Leydig cells. So vitamin D is an important vitamin, certainly once you realise that an overwhelming majority of the western population has too little vitamin D in their blood.

This is because our food contains too little vitamin D, so we have to rely mainly on the vitamin D that our body makes. When exposed to sunlight our skin cells convert cholesterol into vitamin D. But we get too little sunlight and are therefore unable to make enough vitamin D.

So does that mean that most men in the West therefore make too little testosterone?

Study
This is the question that the Austrians set out to answer. So they examined the blood of 2300 men whose average age was just over sixty. Only eleven percent of them had sufficient vitamin D in their blood. And indeed: the more vitamin D the men had in their blood, the higher their testosterone levels and their concentration of free testosterone [FAI].

Now, the concentration of vitamin D in the blood fluctuates with the seasons. The vitamin D concentration is highest after the summer. And this is when the concentration of testosterone in men is highest, according to some studies. [Psychoneuroendocrinology. 2006 Aug;31(7):895-9.] The Austrians were able to confirm this relationship. The testosterone level and vitamin D level rise and fall in synch in the human body.

Supplementation?
So if men make sure they have enough vitamin D in their blood, they'll also make more testosterone. Vitamin D supplements are what come to mind: pretty strong supplements.

But although most multivitamin tablets contain vitamin D, most people who take these kind of supplements only have a slightly higher vitamin D level compared to people who do not take multivitamins. The Austrians also noticed this in their study. "Seventy-eight patients (2.4 per cent) reported taking vitamin supplements on a regular basis, which usually contained vitamin D3. Because 25(OH)D levels were only slightly higher in users of vitamin D preparations (mean 22.1 microg/l) compared with the remaining cohort (mean 17.2 microg/l), we decided to include these patients in the present analyses."

If you look at the table above, you'll see that the effect of multivitamins on the vitamin D level in the blood is too small to boost your testosterone level. You need to think of heavier vitamin D doses, more than 1000 units per pill.

Fifty years ago German sports scientists discovered that power athletes made better progression in the season when they had high vitamin D levels in their blood. Maybe the Austrians have now discovered why.

Source:
Clin Endocrinol (Oxf). 2009 Dec 29. [Epub ahead of print].

More:
Athletes who take vitamin D perform better 03.05.2009
Vitamin D supplement increases muscle strength 13.11.2008