Vitamin D protects a number of important functions in the body.* In addition to supporting healthy bones and muscles, it supports cardiovascular health and immune function.* Although direct sunlight provides natural vitamin D, many individuals of all ages, especially the elderly, do not get enough vitamin D from sunlight and their diet. Vitamin D supplementation can be of great benefit in these situations.* However, the powders used in many pre-mixed vitamin D dilutions frequently contain potentially detrimental ingredients such as lactose, as well as preservatives such as BHT, BHA, sodium benzoate, and sorbic acid. Thorne’s vitamin D is formulated for individuals who are sensitive to those ingredients. In the United States, the current recommended daily intake of 800 IUs vitamin D is based on the minimum amount to protect against bone disease. However, this amount might not be sufficient to support optimal health.* Research suggests serum vitamin D levels should be in the range of 32-80 ng/mL 25-hydroxyvitamin D. The amount of vitamin D needed to achieve minimum vitamin D sufficiency – generally recognized to be a blood level of 32 ng/mL of 25-hydroxyvitamin D – depends on many factors and varies from individual to individual. Thus, the requirement for vitamin D supplementation should be individualized. Either D-1,000 or D-5,000 maybe be ideal to maintain an optimal level of vitamin D in healthy individuals.* D-10,000 is intended for individuals who need higher vitamin D supplementation, and D-25,000 is intended for individuals who need short-term, very high vitamin D supplementation.