Vitamin D can be made by your body when your skin is exposed to sunlight, which is why vitamin D is often referred to as ‘The Sunshine Vitamin'. However, despite the fact that our bodies can make this valuable nutrient, it is thought that Vitamin D deficiency is one of the most common deficiencies in the world.Vitamin D is used by the body in many important processes including:- Helping to support healthy bones and teeth- Supporting the normal absorption and utilisation of calcium- Supporting the healthy function of the immune system- Contributing to normal muscle functionNatures Aid Vitamin D3 4000iu is a super strength product.