Vitamin D3 is essential for strong bones and teeth as it increases the body's absorption of calcium from food.* Its role in regulating calcium levels also helps regulate the immune system and maintain healthy nerves and muscles.* Vitamin D3 is a potent liquid supplement that is carefully blended in a mixture of organic extra-virgin olive and flaxseed oils providing 400 IU of vitamin D3 in just one little drop. Also available in 1000 IU potency for adults.