Everyone needs vitamin D. But not everyone needs the same amount. That’s why we offer the benefits of vitamin D3 in strengths from 1000 IU to 10,000 IU. Why choose Natural Factors vitamin D3 softgels? First, our softgels feature vitamin D3, which is better at raising your 25(OH)D levels than vitamin D2 and lasts longer in your body. Second, our vitamin D3 is delivered in a base of organic flaxseed oil. Because vitamin D is fat-soluble, it’s better absorbed in the presence of fat.