Testosterone and Vitamin K2
Vitamin K2 is not often heralded for having an effect on testosterone production, however, it’s benefits are even greater than that.
We look at the evidence available to put the record straight about K2.
LAST UPDATED: March 2019 by Ben.
All reviews and analytical reports include reliable and reputable source citations, this article includes 11 which can be found at the end of the text.
What do you know about K2?
I am guessing not a lot, because unlike some other vitamins (we’re looking at you C and D) it is not in the spot light that often.
And we think that is unfair.
That is okay though, because you are here, and we are going to run through the facts about vitamin K2, the sources of K2, and also its relationship with testosterone.
Hopefully by the time you have finished reading this informative article you will have a new understanding and a greater appreciation for our humble, yet vital vitamin K.
What is Vitamin K?
Vitamin K is unlike many other vitamins in that we tend not to see it that often supplement format.
You will see many different variants of vitamin C supplements, but barely anything of vitamin K.
However, it really is vital to our health.
For instance, vitamin K helps our blood to clot when we get a cut.
This will prevent excessive bleeding. So, okay, a paper cut is annoying but if you suffer from a deep laceration, vitamin K will be there to help you survive. 
There’s other supporting evidence that state it may also help with bone development. 
In fact it is that vital to our health that in the U.K newborn babies are given an injection of vitamin K to prevent internal bleeding problems.
How much do we require?
It is recommended that adult men intake 120 mcg of vitamin K daily.
However, women also need vitamin K just in a slightly smaller dose of 90 mcg per day.
However, obviously everyone is different and this is a mere suggestion. You may wish to dose it per kilogram of body weight.
Therefore, 1mcg of vitamin K per 1kg.
If you hit this target, you should be okay.
Vitamin K is a compound
Well, vitamin K consists of a number of different compounds. They all work together, but the most important appears to be K1 and K2.
You get K1 and K2 from slightly different food sources.
Like vitamin D, vitamin K is a fat soluble vitamin. 
This means that it is absorbed with fats in the diet and can be stored within the fat tissues.
Not all vitamins and minerals can be stored or produced by the body meaning you have to continuously feed your body.
Vitamin K2 Benefits
Vitamin K1 is much more popular than vitamin K2.
However, this is starting to change because recent science and studies have unearthed the benefits of K2.
The reason behind this growing popularity is down to the half-life of the ingredient.
Vitamin K1 has a much shorter half-life, this means it is out of the system in a matter of 8 hours. As a result it is less biologically active.
On the other hand, vitamin K2 lasts for a much longer 72 hours. This gives your body much more times to utilize it.
It has also been discovered that vitamin K2 is absorbed by the body better than K1 while also directing calcium to the bones.
This prevents calcium from being deposited in places such as the arteries where it can start to form a lining of plaque leading to cardio vascular disease. 
Research demonstrated that K2 was able to reduce the risk of coronary heart disease, cancer, osteoporosis and cardiovascular disease related death. 
So can vitamin K2 even help cancer patients?
It seems so, that’s according to published research by the British Medical Journal.
There’s supporting evidence that vitamin K2 can have a beneficial effect on people suffering from liver cancer and cirrhosis of the liver.
Trials prove that 45mg per day of K2 increased the one year survival rate of patients. 
Studies on K2 have also shown that is can reduce hip, vertebra and non-vertebrae bone fractures by up to 81% when supplemented. 
It is thought that K2 is able to increase bone strength without having an effect on bone density.
Testosterone and Vitamin K2
With the aforementioned benefits outlined you may just be happy with that and wish to ensure you get enough K2 in your diet as it is, without further persuasion.
However, there are even more benefits to vitamin K2, and this concerns its relationship with testosterone.
Vitamin K is distributed to many of the organs and the bones.
- Gonadal tissues
Yes, your gonads. Or, to you and me your testicles. This is where testosterone is produced. 
We can see that already, there is a link.
So how does K2 promote healthy testosterone levels?
Scientific studies have demonstrated that supplementation with vitamin K reduces inflammation and that a deficiency of vitamin K is related to a reduction of natural testosterone secretion.
Trials have seen that in comparison tests those on a vitamin K free diet saw a large reduction of testosterone compared to the group, this was down to a deficiency of vitamin K in the testis.
Studies have confirmed that supplementation of vitamin K prevents a reduction of testicular testosterone synthesis. 
Further analysis discovered that there was a significant increase of testosterone levels of the subjects who were fed a diet with supplemented vitamin K2.
Vitamin K2 is now being considered as a viable supplement to help reduce and reverse the natural depletion of testosterone production in older people. 
Sources of Vitamin K2
So far we have established that Vitamin K consists of a number of compounds, with the most important being K1 and K2.
Latest research now considers K2 to be the most beneficial due to easier absorption and a longer half-life. This means it is biologically available for longer period of time.
K2’s benefits lay with improving bone health, reducing cardiovascular risk as well as increasing life expectancy for liver cancer patients.
K2 has also demonstrated that it can reduce inflammation of the testes and help increase testosterone production.
There are supplements available that contain K2, but let’s concentrate on foods containing K2.
With all of this in mind, some of the the best dietary sources of vitamin K2 are as follows…
Vitamin K2 Food Sources
Luckily, both meat eaters and vegetarians are able to get lots of vitamin K2 in their diet. 
- Green beans
- Grass fed beef products
Vitamin K2 & Testosterone Video Review
Vitamin K2 and Testosterone Conclusion
By using multiple sources of information from reputable organisations we have discovered what vitamin K is and how K2 is the most useful.
We have established that vitamin K2 has numerous health benefits.
This ranges from cardiovascular health, bone strength and those suffering from liver cancer.
Further research has also demonstrated that K2 has abilities to reduce inflammation of the testes and promote testosterone production.
As such, if you are looking to increase your natural testosterone levels, vitamin K2 should not be overlooked.
 Dietary vitamin K alleviates the reduction in testosterone production induced by lipopolysaccharide administration in rat testis. Takumi N, Shirakawa H, Ohsaki Y, Ito A, Watanabe T, Giriwono PE, Sato T, Komai M. Food Funct. 2011 Jul;2(7):406-11. doi: 10.1039/c1fo10058k. Epub 2011 Jun 13. PMID: 21894328
 Menaquinone-4 enhances testosterone production in rats and testis-derived tumor cells. Ito A, Shirakawa H, Takumi N, Minegishi Y, Ohashi A, Howlader ZH, Ohsaki Y, Sato T, Goto T, Komai M. Lipids Health Dis. 2011 Sep 13;10:158. doi: 10.1186/1476-511X-10-158. PMID: 21914161
Ben established this site to be a free resource in 2015. Since then it has gained over half a million visits. It explores the many avenues of fitness and uses supporting scientific evidence for any reviews or analysis of products.
Ben himself has been interested in fitness from an early age. He started playing rugby at the age of 6 for his town, county and school where he gained his full colors while also being in the Army Cadets. After graduating from university in 2005 with a BA(Hons) Ben moved to London and nurtured his love for weightlifting to support his rugby, he also became heavily involved with cycling. Ben also started skiing and recently joined the Army Reserve to further develop his capabilities.