Vitamin K2, pro-testosterone, anti-estrogen, joint repair

Vitamin K, the last fat soluble vitamin discovered, exerts unique and extremely important functions in the body. Vitamin K works in synergy with the other fat soluble vitamins, A, D and E. Although it’s a fat soluble vitamin, the body cannot store large amounts of it, and it gets used up quite quickly. Hence, frequent and adequate dietary K2 consumption is required to maintain optimal levels in the body.

Low levels of vitamin K1 (phylloquinone) is found in many green leafy vegetables as well as a little in olive oil. Beta-carotene is a direct indicator for vitamin K1 in green leafy vegetables. Humans can convert some of the K1 to form the K2 (menaquinone, MK-2 to MK-14), via intestinal bacteria and also an enzyme called UBIAD1, but this conversion is very small and ineffective. (1)

Animals that eat the vitamin K1 rich plants convert the K1 to K2 with their intestinal bacteria, as they are much more effective in this than humans. The K2 is then stored in their tissue, such as organs and fat, as well as in their milk. When the milk is then used to make butter, the color of the butter indicates the amount of beta-carotene and indirectly the amount of K2. The more yellow to orange the butter is (sign of beta-carotene), the more K2 is present. Although, when the animal is able to convert the beta-carotene to retinol, the butter made from their milk will be white, but it still contains significant amounts of K2. Likewise, when cows are given corn, their butter may also be more yellow, but can contain no K2, but only free range animal products will contain significant amounts of K2. Other animal sources such as their liver, pancreas, brain, kidney and dairy also contain good amounts of MK-4 (form of vitamin K2), whereas fermented foods, such as natto and sauerkraut, are higher in MK-7 (form of vitamin K2).

Vitamin K (both K1 and K2) helps with blood coagulation (thickens blood), is anti-tumor, anti-calcification, supports adequate growth, aids in bone-formation and promotes insulin-sensitivity (by keeping pancreas healthy, increasing adiponectin and improving glucose tolerance). (2)

Vitamin K2 also plays a very important role in the immune system. Lymph glands and bone marrow accumulate large amounts of it and a vitamin K-dependent protein called gas6 plays a role in phagocytosis (the process when immune cells destroy and consume foreign cells or the body’s own cells when they are infected or no longer needed, or simply put, good cells eat bad cells), exerts remarkable anti-proliferative effects on cancer cells, and protects against apoptosis (cell death).

Improves bone, joint and artery health

Vitamin K acts as a cofactor in the conversion of glutamate into Gla (gamma- carboxyglutamic). Gla-containing proteins, MGP and osteocalcin are involved in collagen matrix formation and calcification of the bones, respectively.

Vitamin K2 further activates osteocalcin (the bone-forming protein synthesized by osteoblast) and matrix-Gla protein (MGP) (an anti-calcification protein synthesized in blood vessels) by attaching carbon dioxide to it. Once active, these proteins can now move to the correct location and exert their functions. But with inadequate vitamin K2, these proteins stay inactive and can lead to calcification of soft tissue and cartilage, instead of taking the calcium to the bones and collagen matrix.

Vitamin K2 aids in healing and strengthening joints.

Both vitamins A and D are very important in regulating bone growth, and when the ratio of vitamin A and vitamin D are out of balance, proper bone growth cannot take place and problems occur. That’s why some people think vitamin A and/or D is toxic (which is true in high isolated doses), but they just need to be in balance and allow it to work in synergy with K2.

Improves blood coagulation

Blood coagulation helps to regulate its viscosity, and prevents excess bleeding and bleeding related illnesses.

K1 and K2 (MK-7) is involved in blood coagulation. Vitamin K increases pro-coagulation factors II, VII, IX, X and anti-coagulation factors namely protein C and protein S, to provide control and a balance in the coagulation cascade.

Furthermore, gamma-glutamyl carboxylase, a liver enzyme that metabolizes oxalate, is catalyzed by vitamin K. (3) A deficiency in vitamin K can lead to impaired oxalate metabolism and thus lead to kidney stone formation.

Lowers estrogen and increases DHEA

17 beta-Hydroxysteroid dehydrogenase (17 beta-HSD) is the enzyme that controls the last step in the formation of all androgens and all estrogens. There are 5 types of this enzyme.

Vitamin K2 binds to 17 beta-HSD type 4, which degrades 17 beta-estradiol into estrone and decreases the intracellular estradiol:estrone ratio, which results in the inhibition of the amount of estrogen receptor alpha (ER)-binding to its target DNA, due to less estrogen to receptor interaction. (3)

And that’s not all, type 4 17 beta-HSD also converts androst-5-ene-3 beta and 17 beta-diol (androstenediol) into dehydroepiandrosterone (DHEA). DHEA can then be converted to testosterone or estrogen, so it’s always a good idea to keep the aromatase inhibited.

Vitamin K2 decreases estradiol (the most powerful estrogen) as well as increases DHEA at the same time.

Increases testosterone

Vitamin K is important for the post translation of Gla proteins in various tissues, including the testes and are directly involved in steroidogenesis. The mRNA of steroidogenic genes are low in vitamin K deficient tissue.

In this study, rats were given 75mg/kg MK-4 for 5 weeks and their testosterone increased significantly. MK-4 is the prodominate vitamin K form present in the testes.

The MK-4 increases protein kinase A (PKA) signalling, which stimulates the steroidogenic acute regulatory protein (StAR) to transport cholesterol from the outer to the inner mitochondria. Furthermore, MK-4 increases CYP11A activity and also its mRNA gene expression. CYP11A is the enzyme that coverts cholesterol into pregnenolone (the first steroid).

The increase in testosterone is independent of LH secretion as LH remains unchanged with vitamin K2 administration.

As the study concluded: “expression of CYP11A, the rate-limiting enzyme in steroidogenesis, and phosphorylation levels of protein kinase A (PKA) and the cAMP response element-binding protein were all stimulated by the presence of MK-4” (4)

Also, osteocalcin, produced by the skeleton’s bone-building osteoblast cells, stimulates testosterone production, however, osteocalcin is only synthesized by vitamin K2 and vitamin D. (S) More on osteocalcin here

Vitamin K2 helps with energy

“Mitochondrial dysfunction was rescued by vitamin K(2) that serves as a mitochondrial electron carrier, helping to maintain normal ATP production”. (5) Which can be a very effective tool against prolactin, as prolactin increase when the mitochondria is under stress and is not producing enough ATP. More about lowering prolactin here

Selecting your supplement

Bio-availability of MK-4 might not be very good, as a supplementation of 500 μg (0.5mg) MK-4/day for 2 months showed no effects on carboxylation of osteocalcin, whereas a dose of 1500μg (1.5mg) MK-4/day was required to improve carboxylation of osteocalcin.

MK-7 is greater and lasts longer which is better for blood coagulation than K1 and MK-4. It has a very long half-life in serum (after a dose of 420ug (0.42mg), levels was still detected after 48 hours). (6) MK-7 are also better at increasing MK-4 levels, than MK-4 itself.

MK-4 can be mega-dosed at 45mg a day without adverse side affects.

Nutrient interactions

Large doses of vitamin A and vitamin E have been found to antagonize vitamin K (7). Excess vitamin A appears to interfere with vitamin K absorption, whereas vitamin E may inhibit vitamin K-dependent carboxylase activity and interfere with the coagulation cascade. (8) This is only for very high doses of vitamin A and E, and is very likely not a problem with logical supplemental or dietary amounts.

Smaller amounts such as 100-200IU vitamin E and <5 000IU vitamin A might not have the same interfering effects. Just to be safe, take K2 and vitamin E about 6 hours apart if larger doses are to be taken.

Vitamin K2 synergists: Calcium, copper, vitamin B5, vitamin D (dose dependent), flavonoids

Vitamin K2 antagonists: oxalates, alcohol, coenzyme Q10, antibiotics


Kuinone – highly bio-available liquid vitamin K2 (MK-4). 1.5mg per serving, 720 serving per container

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9 thoughts on “Vitamin K2, pro-testosterone, anti-estrogen, joint repair”

  1. Hello Hans, I wanted to know something, Carlson’s vitamin K2 contains 5mg, it is advisable to take one capsule a day without creating toxicity? Since when I add it to the chronometer application I get that it is 42167% of the daily amount, it is problematic or having little assimilation does not matter?
    I also wanted to tell you that I am consuming with the diet around 2.4gr of calcium from whole goat yogurts, and supplementing with 4000iu of vitamin D and 250mg of magnesium, how do you see that? Thank you

    • Hey Diego,
      5mg K2 MK-4 is perfectly safe long-term. Studies even use up to 90mg daily long-term for osteoporosis. 2.4g calcium daily is also perfectly safe. I’ve been consuming around 4-6g daily for a couple years now. Dietary calcium is great for supporting health and the metabolism.


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