provides vitamin d3 400iu, as recommended by the department of health ,for the maintenance of normal bones, teeth, muscle function, and immunity ,easy-to-swallow, one-a-day, vegetarian-friendly formula for more information, please read our |vitamin d faq//b111//class=f-brand !important| our convenient, one-a-day vitamin d3 400iu tablets provide the department of health-recommended amount of vitamin d all uk adults should consider taking throughout the winter months. this level is an excellent choice if you want to top-up your vitamin d intake or combine it with one of our comprehensive multivitamins, most of which already supply 400iu vitamin d3. if you get very little sun exposure, we recommend our higher strength |vitamin d3 1000iu//p509//class=f-brand !important| product.our pure-grade vitamin d3 400iu delivers the preferred form of vitamin d (cholecalciferol or vitamin d3), which is naturally synthesised in the body when sunlight directly hits the skin. the body absorbs vitamin d3 much better than the d2 form (ergocalciferol) made from plants. we\'ve chosen to provide this strength of vitamin d3 in tablets, not capsules, since this product is recommended as a top-up level, best taken alongside a multi with magnesium, zinc and vitamin k, which all increase vitamin d absorption. we manufacture and package our vitamin d3 400iu in uk factories working to good manufacturing practice (gmp) to ensure our quality standards are always met. since vitamin d3 400iu is made from cholecalciferol, it\'s suitable for vegetarians not vegans. however, if you\'re looking for a plant-based alternative, you can try our |vegan vitamin d 1000iu//p502//class=f-brand !important|. still unsure of which vitamin d3 product to choose? don\'t worry. we have a team of friendly |nutrition advisors//aadvice//class=f-brand !important| on hand to help you pick from our extensive vitamin d3 offerings. simply click the \'nutrition advice\' button located at the bottom right-hand of our website to start a live chat. learn more about the |health implications of low vitamin d levels here//b777//class=f-brand !important|. what does vitamin d3 contribute to? vitamin d3 contributes to the normal absorption and utilisation of calcium/phosphorus and the maintenance of normal bones, teeth, and muscle function. it also contributes to normal cell division, the normal function of the immune system and healthy inflammatory responses.