Bioclinic Naturals Opti Active D 60t Opti Active D contains ampli-D, a highly bioavailable form of vitamin D, which has been clinically demonstrated to increase and optimise endogenous vitamin D status more rapidly than the colecalciferol form. Vitamin D is essential for maintaining homeostasis in many physiological functions and processes in the body including immune activity, bone health and healthy pregnancy and foetal development. Contains world-first ampli-D calcifediol monohydrate, a highly bioavailable form of vitamin D. Calcifediol is the circulating form of vitamin D in the body, so that it does not need to be metabolised by the liver and is immediately available for use. Therefore ampli-D is an extremely easily absorbed form of vitamin D. Raises vitamin D levels faster than vitamin D3. ampli-D is clinically demonstrated to have 3 x per microgram superior bioavailability than colecalciferol, so that lower dosages are required. Convenient 1 tablet per day dose for improved compliance.