Vitamin D is an essential vitamin that is necessary to regulate calcium and phosphorus in bones and impacts many organ systems including the endocrine system and immune system (1). Vitamin D3 5000 IU Softgels Benefits Promotes a healthy immune system (ref)* and regulates immune system responses (ref)* May increase cognitive function (ref)* Vitamin D3 has been shown to raise the levels of Vitamin D in the blood faster than D2 (ref)* Vitamin D3 5000 IU Softgels Mode of Action Vitamin D comes in two supplemental forms, D3 (cholecalciferol) and D2 (ergocalciferol). D2 is found mostly in plants, such as mushrooms, and D3 is found in animals and produced in human skin when exposed to sunlight (2). Vitamin D is commonly fortified (added) in foods such as fortified milk, orange juice, and cereals (3) but is also present in fatty fish (2). Human skin produces D3 when exposed to sunlight but the factors that are involved in the synthesis of Vitamin D through sunlight alone are so variable that most of the population has an insufficient level of Vitamin D—over 1 billion people worldwide are deficient (4). Skin exposed to direct sunlight begins to make Vitamin D but the amount and efficiency of attaining Vitamin D through this method depends on where you live geographically on earth, what time of day it is, what time of year it is, how much skin is exposed, how old you are, the altitude, if there are clouds, air pollution, sunscreen use, being behind glass—and also if you are dark or light skinned. Your skin type affects how much UVB light is absorbed, and therefore how much Vitamin D is produced. It could take up to six times longer to absorb adequate UVB sunlight to produce your body’s needs for Vitamin D if you are darker skinned (3). Vitamin D3 5000 IU Softgels Dosage Pure Nootropics’ Vitamin D3 Softgels deliver 5,000 IU Vitamin D3 per 1 capsule and are best suited for individuals who have been advised on supplementation with this amount of D3. Suggested use for adults is 1 capsule by mouth once daily, or as directed by your healthcare practitioner.* Dosages vary depending on your resource and Pure Nootropics recommends that you work with a healthcare practitioner to determine a regimen that best suits your needs. It is possible to consume too much Vitamin D through supplements, so careful monitoring with a blood test that measures [25(OH)D] every 3-6 months is needed with this supplement. There is much debate on how much Vitamin D is necessary to gain the benefits it has to offer. Your healthcare practitioner will advise you on the best amount to take (3).   Vitamin D3 5000 IU Softgels Side Effects and Toxicity Vitamin D in large doses of more than 10,000-40,000 IU/day for more than a few months can cause toxicity (3).   For further information, please see our References Tab above.