Vitamin K1 (phylloquinone) is mainly found in green leafy vegetables and is primarily associated with diet. Vitamin K2 (menaquinones) is found in fermented products and animal foods. K2 has several subforms, of which menaquinone-7 (MK-7) is a commonly used variant in supplements because of its longer presence in the body.

Menaquinone-7 is a specific form of vitamin K2 that is obtained via fermentation (e.g. from natto). This form is often chosen for supplements because of its stability and the possibility of low dosing per capsule.

Vitamin D2 (ergocalciferol) is of plant origin, while vitamin D3 (cholecalciferol) is usually from animal sources, such as wool fat (lanolin).

Both vitamin D and K are fat-soluble. An oil base, such as MCT oil, ensures good distribution of the fat-soluble substances in the capsule and is common in this type of supplement.

A meal usually contains fats, which can support the absorption of fat-soluble vitamins such as D3 and K2. That is why it is often recommended to take fat-soluble supplements during or after a meal containing some fat.