4000iu Vitamin D3 & 100ug K2 MK-7 Tablets. Support your immune system, bones, muscles, and teeth with clinically-backed nutritional benefits. The Perfect Pairing: Vitamin D3 & K2. Sourced from lanolin (cholecalciferol) for Vitamin D3 and MK-7 for Vitamin K2, these forms are widely regarded as the gold standard for maximum bioavailability.