Research has suggested that we may need much more vitamin D than previously thought for optimum immune support and long-term health.* Cholecalciferol, also known as Vitamin D3, is more biologically active in the body than vitamin D2.* In some climates people may get adequate vitamin D3 from sunlight, but in cooler climates at higher latitudes, with longer winters, vitamin D deficiency may occur with greater frequency.* <p></p> The amount of vitamin D3 that an individual needs varies due to a variety of factors, but for many individuals vitamin D intake may not be enough to provide complete health benefits.* Some factors that contribute to vitamin D deficiency include: <p></p> Spending most of the day indoors. <p></p> Using sunscreen. <p></p> Wintertime & less sunny climates. <p></p> Darker skin tone (melanin blocks UVB rays, which facilitate vitamin D production in the skin). <p></p> Vitamin D3 5000 IU by Seeking Health provides pure and potent Vitamin D3 as cholecalciferol in each vegetarian capsule. Vitamin D3 occurs naturally in fatty fish, cod liver oil, egg yolks, and beef liver. This can make it more difficult for vegans and vegetarians to consume adequate vitamin D from their diet.* Vitamin D3 5000 IU uses cholecalciferol derived from cholesterol in sheep’s wool, making it suitable for vegetarians.*