Vitamin D"s pivotal role in bone health is no secret to doctors. Vitamin D is essential for the functioning of many important systems in the body, and recent research has suggested that we may need much more vitamin D than previously thought for optimum immune function and long-term health. Adequate vitamin D levels may reduce the risk of many chronic diseases in the long term, including: Autoimmune Disorders1 Diabetes4 Cancer2,3,4 Osteoporosis4 Rheumathoid Arthritis4 High Blood Pressure4. Most people diets alone does not supply them with sufficient amounts of vitamin D3, and the synthetic vitamin D2 that is added to dairy products is an inferior form of this vital nutrient, and is added in too small of an amount. Good food sources for Vitamin D3 are found in fatty fish (such as tuna and salmon), cod liver oil, egg yolks, and liver. The sun is also an excellent source for vitamin D3 (assuming your skin is sunscreen free). There are many factors that contribute to vitamin D deficiency such as: Using sunscreen while in the sun, Spending most of the day indoors, Wintertime and living in areas with a less sunny climate . Darker skin tone (melanin blocks UVB rays, which produce vitamin D in the skin) Senior citizens tend to be more at risk because they may also be taking prescription drugs that can interfere with vitamin D metabolism. Other people who need to take special care that they get enough vitamin D are vegetarians, post menopausal women and alcoholics. Advice for use: Adults take 4 drops(400IU) 1 to 5 times daily. Doses in excess of 400 IU should not be taken without a doctor"s supervision. Vitamin D deficiency symptoms vary depending on the individual, so consult with a physician to test vitamin D levels before taking more than the recommended dosage. Larger doses could raise calcium levels in the blood and could have serious health effects. This product is NOT manufactured with yeast, wheat, gluten, soy, milk, egg, fish or shellfish.