10 drops contain 5,000 IU vitamin D3 and 1 mg vitamin K2. Vitamin K2 exerts a more powerful influence on bone than does vitamin K1.* Vitamin K2 is a series of molecules known as menaquinones. The most common and well studied of the menaquinones is MK-4. Thorne's vitamin K2 is MK-4 and is derived from bacterial fermentation; thus, there is no soy in the product. Vitamin K is also essential for normal cell formation and maintenance of a healthy cardiovascular system.* It is essential to maintain healthy vitamin D levels throughout all stages of life, from fetal development to old age.* Vitamin D helps protect a number of important systems in the body, including healthy bones, immunity, and cardiovascular function.* Combining vitamins D and K may provide even better protection of these systems.* One study in postmenopausal women found a combination of minerals with vitamins D and K maintained healthy artery elasticity, compared to two other groups of women who received either minerals with vitamin D but not K, or placebo.* Thorne's Vitamin D / K2 Liquid is in medium chain triglyceride oil, preserved with mixed tocopherols.