Technically Vitmain D isn’t a vitamin at all, it’s a secosteroid (literally meaning ‘broken steroid’) which is a subclass of steroids. You might also find it referred to as a ‘pro-hormone’.
Vitamin D is normally associated with healthy bones and teeth, but is important for the endocrine system. It is responsible for improving the intestines’ ability to absorb zinc, phosphate, magnesium, iron and calcium.
Vitamin D is found in very few food sources (fish and eggs excepted), but your body is able to manufacture it’s own vitamin D from sunlight. It is estimated that 5 to 10 minutes of direct sun exposure two or three times a week is sufficient to generate enough vitamin D to keep an adult healthy.
This doesn’t sound like much but vitamin D deficiency is surprisingly prevalent in northern latitudes mainly due to our indoors lifestyles and work schedules (we’re talking about the USA and Europe here, not Siberia, Iceland and Svalbard). Sunblock also reduces the body’s ability to convert sunlight into vitamin D, with SPF30 sunblock capable of reducing vitamin D conversion by up to 95%.
When you are reading about vitamin D you’ll find reference to both D2 and D3. What’s the difference? Vitamin D2 is calciferol and D3 is cholecalciferol. Vitamin D3 is the type your body makes naturally when converting sunlight. D2 is a plant based extract. We will be focusing on D3 for the remainder of the article, and will refer to vitamin D from now on meaning D3.
One of the things you’ll discover when you start to research natural ways to boost testosterone is that there are numerous ingredients and combinations where efficacy is disputed. Clinical evidence is contradictory, there are competing interests, and as a result it’s not clear cut whether those formulations are effective at boosting test.
What really jumps out at you with vitamin D is not just the huge body of clinical research that’s been done on humans in relation to the effects on testosterone. Or the large participant numbers in those studies. Or even the fact that some of them were conducted over long periods, in some cases years.
It’s the fact that the body of evidence in favour of vitamin D supplementation in relation to test is so unamimously positive that it’s difficult to refute.
Let’s work our way through them, starting with the most recent.
This study piggy-backed onto another study into prostate cancer involving 1362 male participants, by measuring their vitamin D levels as well as their total and free testosterone levels.
The results showed that both total and free test levels were both positively associated, and that this relationship estood for all four quintiles. By which we are saying that it’s not just the case that vitamin D supplementation will increase test levels in the case of vitamin D deficiency, the relationship was found to be linear right up until the highest levels of vitamin D.
An incremental percentage of additional vitamin D would result in an equivalent percentage increase in both total and free testosterone. This continues until a saturation point is reached, after which additional vitamin D does not result in additional testosterone, but this only occurs at very high levels.
The aim of this clinical study was to establish whether vitamin D supplementation affected testosterone levels in men. The study was conducted on 200 men between the ages of 20 and 49, and lasted for 1 year.
The non-placebo group took 83 micrograms (µg) of vitamin D every day.
The study found a significant increase in total testosterone levels, from an average of 10.7 to an average of 13.4 (an increase of 25.2%), and free testosterone levels went up from an average of 0.222 to an average of 0.267 (an increase of 20.2%).
This wasn’t a trial as such, this was a study conducted on 2299 men who were referred to the Medical University as patients for coronary angiography over a three year period. They all had their vitamin D, testosterone and SHBG levels checked whilst they were there.
Men with healthy levels of vitamin D had significantly higher levels of testosterone and significantly lower levels of SHBG. SHBG is a protein which binds to testosterone and renders it unusable by androgen receptors.
The more SHBG you have in your system, the lower your free testosterone levels (this is the test which provides the benefits we are looking for). This means that the men with healthy vitamin D levels would therefore ahve had higher free test levels.
This was not a clinical trial, more of a study done on hospital patients who were in the hospital anyway – in this case all the patients who were admitted through 1995 with hip fractures (123 subjects in the study in total).
The study found that vitamin D deficiency was the strongest predictor of hip fractures. Inpatients, who would have spent some time in the hospital recovering from their hip fractures and therefore would not have been spending time in the Australian sun, had significantly lower vitamin D and free testosterone concentrations than outpatients.
So importantly not just a significant link not just between vitamin D and testosterone but between vitamin D and free testosterone.
Does it need saying? If you are interested in your test levels then you should be interested in your Vitamin D levels. If you live in North America or Northern Europe and work indoors there’s a high chance your Vitamin D levels are low.
You can boost your levels by using sunbeds… with the unfortunate downside that you increase your chances of skin cancer. You can buy a Vitamin D supplement or you can buy a combined test boosting supplement containing Vit D.
If you are looking at combined supplements then make sure you look at the dosages as well as whether it contains Vitamin D. We’ve seen quite a few supplements claim to contain it but when you look a bit more closely you realise the quantities are tiny.
With evidence like that it’s fair to say that you should avoid any test boosting supplement that doesn’t include vitamin D. Make sure the dosages