I follow a ton of medical journals and health and fitness-related blogs, and one topic doing the rounds lately that I have already promised to discuss in a previous article is vitamin D. And thus, without further ado.
Let me first state what vitamin D is not; a single compound. It is actually a group of several compounds. Due to medical breakthroughs occurring at various rates, vitamin D was grouped with the other vitamins as a single entity until new research shed light on other entities within the group and their roles in biochemistry. With new research coming out, people finally appear to be referring to the specific subtypes in articles and journals, much like they are specific with which B-vitamin they are referring to when discussing them. And the type of vitamin D people seem to be most interested in lately is vitamin D3, hereby known throughout this article as the incredibly complex ‘D3’.
Believe it or not, but D3 is actually a hormone precursor, or ‘prohormone’. It is synthesized in the skin when ultraviolet light from the sun reacts with a type of cholesterol in the skin. D3 is then passed to the liver where it is converted to calcidiol, and this is in turn passed to the kidney to become calcitriol, the active form in the body. The more astute of you will have realized the importance of the sun for this to occur, and will be pondering the impact of the darker winter months that so many of us have to live through. It’s true that the average Joe notes a decline in vitamin D over winter. Some sharp thinkers may be thinking that a few blasts in the tanning salon should make up for it, but I am afraid that may not be the case. The type of UV light required for the conversion to D3 in the skin is UVB while tanning beds typically emit 95% UVA and only 5% UVB. We can get some through food sources, but the foods that actually contain vitamin D such as oily fish, meat and eggs are not exactly exploding at the seams with the stuff, so supplementation may be a good idea. But why, I hear you cry.
Vitamin D is associated with a magnitude of benefits including fat loss, insulin sensitivity, improved blood pressure, stronger immune response and a decrease in heart disease. These should be enough to warrant ensuring you have sufficient intake, but the effect I am most interested in for this article is the potential impact vitamin D levels can have on testosterone. This stems from recent research coming out of Austria looking at any correlation between levels of vitamin D and androgens in order to assess any seasonal variation between the two. What they found was that men with sufficient vitamin D were found to have the highest testosterone and lowest sex hormone-binding globulin (SHBG). SHBG is a protein that renders androgens inactive when bound. The researchers also found that levels peaked in August, during the height of the summer for the Northern hemisphere. So if you live in the north and experience months of low sunlight, taking some D3 may be a good idea, even if just for the winter. There are even some parties who claim that D3 has alleviated their seasonal-affecting disorder (S.A.D. or “winter blues” as it is colloquially known) but medical research is somewhat conflicting.
So fundamentally, I support the use of D3 supplementation to ensure adequate amounts to ensure there is no decline in testosterone during sunless-months. But some of the news articles and blogs I read stemming from this research lead to the conclusion that sunlight can boost testosterone, leading to an increase in libido. This is a somewhat narrow-minded conclusion as there are so many more players in the “libidostat”, a word I just made up. However there is definitely something from sunshine that raises libido. And I’m not just talking about men either – women tend to become more forward and wear more revealing clothes in the summer and it’s not just because it is warmer. This is also connected to D3, because the skin pigment Melanin is a filter that controls how much UVB gets through the skin to affect D3 synthesis. Sunlight appears to have a positive effect on melanin by stimulating its release from melanocytes which increases sexual arousal, and also strangely effects appetite. Some pharmaceutical companies have taken advantage of this which you may have heard of under the name “Melanotan”. While Melanotan is used for increasing a person’s tan, it was born from research looking into a solution for erectile dysfunction under the brand name Bremelanotide (which never made it to market due to health concerns).
That’s all for now, but I promise to revisit this topic again in the future with more specific detail into some of the benefits of D3.
Source: Wehr E, Pilz S, Boehm BO, März W, Obermayer-Pietsch B. Association of vitamin D status with serum androgen levels in men. Clin Endocrinol (Oxf). 2009 Dec 29.
Matt Cahill has worked extensively in the nutritional supplement field, and is the former CEO of Designer Supplements. During his time in the field has researched and developed prohormones, testosterone boosters, and other related compounds, both for his own company and others. 
Tsk Tsk… There is a very fundamental flaw in the above review.
There are a number of studies that show that manufactured Vitamin D3 is not nearly as effective as the D3 made naturally by our body’s reaction to sunlight.
You were correct in stating that tanning beds emit about 5% UVB to about 95% UVA but you failed to realize that that ratio is almost identical to that issued by teh sun.
Ergo… if sunlight is the best way to get the right D3 as well as enough of it, then tanning beds are the next best thing to the sun but offer the benefits of privacy, monitoring, and convenience. I predict that in a few short years there will be far more tanning beds in homes than hot tubs!
By the way… the sun (and therefore tanning beds) causes the body to produce roughly 20-25,000 IUs of D3.
If either G-d or evolution (your choice) caused our body’s to react to the sun in such a manner producing such a large amount of D3, then that is what we probably need.
The recommended dosage of 400 IU’s of D3 (forget about the cheap substitute D2) was meant as the minimum that a small child needs in order to combat rickets.
Over the last number of years there has been more and more evidence that D3 receptors are found on so many more of the cell in our organs that 400 IUs is just so far away from the necessary amounts. so… aim for 10-25,000 IUs daily and the only way you’re going to get that is by exposure of most of our body to sunlight whether from the sun or tanning lamps.
Why didn’t we hear about this until now? The medical and pharmaceutical mega-industry cannot afford to have people healthy… healthy people don’t need pills or treatments and if suddenly a tremendous number of people started tanning for their D3, the industry would deflate like a burst balloon.
The medical and pharmaceutical mega-industry’s raison d’etre is pure profit motivated. They are NOT in the health business, they are in the curing business and rely on us to become sick and in-firmed and at death’s door… that’s the way they want us!
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