Vitamin K2 (MK-7)
Menaquinone-7
A fat-soluble vitamin that directs calcium into bone and away from soft tissue, studied for its role in cardiovascular protection, bone density, and safe high-dose Vitamin D3 supplementation.
The Ingredient Explained
Vitamin K2 MK-7 is the most bioavailable and longest-acting form of K2 available. Unlike K1, which is involved in blood clotting, K2 activates proteins that govern where calcium goes in the body. The two most important are osteocalcin, which binds calcium into bone, and matrix Gla protein, which prevents calcium from depositing in arterial walls and soft tissue. MK-7 has the longest half-life of any K2 form, meaning a single daily dose keeps those proteins activated around the clock. Foundation uses 120 mcg because that's the dose shown to fully activate matrix Gla protein in clinical studies.
Why it's in Foundation
Foundation includes 5,000 IU of Vitamin D3 per serving. At that dose, D3 significantly increases calcium absorption from food and supplementation. That's exactly what you want for bone density and hormonal function. But calcium that enters the body needs to be directed correctly. Without adequate K2, high-dose D3 supplementation can lead to calcium depositing in arteries and soft tissue rather than bone. K2 MK-7 is the mechanism that makes high-dose D3 both effective and safe long-term. It's not in Foundation as a bonus ingredient. It's in Foundation because leaving it out would be irresponsible.
Your 90-Day Timeline.
K2 begins optimizing calcium metabolism immediately. While effects on testosterone take longer to measure, the protective role alongside D3 is active from day one.
The synergistic effect with D3 becomes measurable. K2 is working in the background ensuring D3 is converting and directing properly throughout this period.
Long-term K2 supplementation shows the strongest effects on testosterone-related markers. Consistent use alongside D3 is where the combined benefit compounds.
What the research shows
120 mcg MK-7. Enough to fully activate matrix Gla protein.
Research shows that 90 to 120 mcg of MK-7 daily is sufficient to fully activate matrix Gla protein, the primary protein responsible for preventing arterial calcification. Studies also show MK-7 supplementation improves bone mineral density and reduces arterial stiffness over time. Foundation uses 120 mcg, the top of the clinically studied range, using the MK-7 form specifically because of its superior half-life and bioavailability compared to MK-4.
View the human study
MK-7 and matrix Gla protein activation, published clinical trial
How it works with other ingredients
Vitamin D3
D3 drives calcium absorption. K2 directs where that calcium goes. Neither works optimally without the other at meaningful doses. This is the most clinically established nutritional pairing in Foundation and the reason both are included at therapeutic levels.
Boron
Boron reduces SHBG and supports bone metabolism through overlapping pathways with K2. Both work on the structural systems that vitamin D3 influences, making the three a complementary cluster within the formula.
Zinc
Zinc supports testosterone synthesis at the testicular level. K2 protects the cardiovascular system that delivers the hormones zinc helps produce. One works on the output, the other protects the system that carries it.