Does Vitamin K2 Increase Testosterone?

By Noophoric Editorial Team Updated August 31, 2026

Vitamin K2 is important for normal blood clotting and the activation of proteins involved in bone and cardiovascular health. Interest in testosterone comes from laboratory and animal research showing that menaquinone-4, a form of K2, can influence steroid production in testicular cells. Direct human evidence for a testosterone increase is still limited, so K2 is best viewed as a foundational men’s-health nutrient rather than a stand-alone hormone treatment.

That distinction does not make K2 unimportant. Men need strong bones, healthy calcium metabolism, and adequate micronutrient status throughout life, especially because testosterone health and bone health are closely connected.

What is vitamin K2?

Vitamin K is a family of fat-soluble compounds. Vitamin K1, or phylloquinone, is abundant in leafy green vegetables. Vitamin K2 refers to menaquinones, often written as MK followed by a number. MK-4 and MK-7 are common supplemental forms.

All vitamin K forms help activate proteins through a process called gamma-carboxylation. Some of those proteins are required for normal coagulation, while others help regulate where calcium is used in the body.

Why K2 is connected with testosterone

Researchers have found vitamin K compounds in gonadal tissue, which raised questions about a role beyond clotting and bone. In a rat and cell study, supplemental MK-4 increased testosterone production and affected signaling involved in steroidogenesis. Another rat study found that dietary vitamin K helped offset reduced testicular testosterone production during experimentally induced inflammation.

These studies are useful for understanding mechanism, but animal doses and cell experiments cannot establish a testosterone benefit in men. They provide a reason for further research, not a reason to promise a specific hormone change.

What human research can and cannot tell us

At present, well-controlled human trials designed specifically to test vitamin K2 as a testosterone intervention are lacking. That means the claim “K2 increases testosterone” is ahead of the clinical evidence.

A more accurate position is that vitamin K2 supports established aspects of men’s health and has an interesting preclinical connection to steroid production. In a comprehensive formula, it can sit alongside ingredients with direct human research rather than carrying the entire testosterone claim by itself.

K2, vitamin D3, calcium, and bone health

Vitamin D supports calcium absorption and normal bone mineralization. Vitamin K activates bone proteins such as osteocalcin. Because these nutrients participate in related processes, they are frequently paired in supplements.

Men with clinically low testosterone can face greater bone-health risk, which makes adequate vitamin D, vitamin K, calcium, protein, and resistance exercise especially relevant. Our guide to vitamin D3 and K2 together explains the complementary roles without implying that one nutrient directs calcium on its own.

How K2 fits into a testosterone-support formula

Healthy testosterone production depends on a network of signals and nutrients. A formula can combine foundational vitamins and minerals with botanical extracts that have human research related to stress, libido, body composition, or testosterone.

Noophoric Men’s+ provides 100 mcg of vitamin K2 along with vitamin D3, zinc, boron, KSM-66 ashwagandha, tongkat ali, fenugreek, Coleus forskohlii, and other ingredients in a daily formula designed to support healthy testosterone levels, energy, drive, and resilience.*

For men focused primarily on foundational bone and immune support, Noophoric D3 + K2 Complex combines 5,000 IU of vitamin D3, 100 mcg of vitamin K2, 210 mg of calcium, and BioPerine.*

Food sources of vitamin K

Leafy greens such as kale, spinach, collards, and broccoli provide vitamin K1. K2 occurs in smaller amounts in fermented foods and certain animal foods. Natto is especially high in MK-7, while some cheeses, egg yolks, and meats provide varying menaquinones.

Gut bacteria also produce menaquinones, but it is not clear how much this contributes to human vitamin K status. A varied diet remains the foundation.

MK-4 vs. MK-7

MK-4 and MK-7 differ in source, metabolism, and time in circulation. MK-4 was used in the preclinical testosterone research. MK-7 remains in blood longer and is commonly used in once-daily supplements.

There is no human evidence showing that one form is the best testosterone booster. Choose based on the complete product, intended use, dose, quality, and medical context rather than assuming the longest half-life equals the largest benefit.

Safety and blood-thinner interactions

Vitamin K has no established tolerable upper intake level because toxicity from food and typical supplement use appears low. The most important caution is medication interaction. Vitamin K can reduce the effect of warfarin and related vitamin K antagonist anticoagulants.

People taking warfarin should not abruptly add, remove, or change a K2 supplement without guidance. Consistency of vitamin K intake is often important, and the prescribing clinician manages the medication around that pattern.

Vitamin K does not have the same interaction with every anticoagulant, but anyone taking blood-thinning medication should still ask a pharmacist or clinician before adding it.

How to support testosterone beyond one nutrient

Micronutrients work within a larger system. Adequate sleep, resistance training, sufficient calories and protein, healthy body composition, and treatment of sleep apnea or other medical issues can all matter. Our article on natural testosterone support brings these pieces together.

If symptoms are persistent, do not use a supplement response as a diagnosis. Correct testosterone testing normally involves at least two early-morning measurements and clinical interpretation.

Frequently asked questions

Does vitamin K2 increase testosterone?

Animal and cell studies suggest MK-4 can influence testosterone production, but controlled human trials confirming a testosterone increase are lacking. K2 still has established roles in normal vitamin K function and bone health.

Should men take vitamin K2 with vitamin D3?

They are commonly paired because vitamin D and vitamin K participate in complementary aspects of calcium and bone metabolism. The right dose depends on diet, vitamin D status, medication, and health history.

Is MK-4 or MK-7 better?

Both are vitamin K2 forms. MK-4 has been used in preclinical testosterone studies, while MK-7 has a longer circulating half-life. There is no human proof that one is superior for testosterone.

Can K2 replace testosterone therapy?

No. Vitamin K2 is a nutrient. Men with confirmed hypogonadism need individualized evaluation and discussion of treatment options with a qualified clinician.

Who should not take K2 without medical guidance?

Anyone using warfarin or another vitamin K antagonist should consult the clinician managing the medication before changing vitamin K intake.

Bottom line

Vitamin K2 is an important men’s-health nutrient with established roles in vitamin K dependent proteins and bone health. Its testosterone connection is biologically interesting but currently based mainly on animal and cell research. K2 can be a sensible part of a complete D3 and K2 or testosterone-support formula, while direct hormone claims should rest on the evidence for the whole routine and the other ingredients involved.

Sources

Evidence reviewed August 2026. This article is educational and is not a substitute for individualized medical diagnosis or treatment. *These statements have not been evaluated by the Food and Drug Administration. Noophoric products are not intended to diagnose, treat, cure, or prevent any disease.