What is vitamin D3 good for? Vitamin D (ergocalciferol-D2, cholecalciferol-D3, alfacalcidol) is a fat-soluble vitamin that helps your body absorb calcium and phosphorus. Having the right amount of vitamin D, calcium, and phosphorus is important for building and keeping strong bones.Vitamin D3 offers many health benefits. It is known to help strengthen bones and muscles, boost immunity, increase mood, aid in weight loss, and improve heart function.
