Vitamin D3 (“Cholecalciferol”) belongs to a group of fat soluble Compounds belonging to the “Vitamin D” family and one of its main tasks is it to maintain our body’s mineral balance. It is an essential compound for ensuring continuous and sufficient calcium and phosphor (mainly found in milk and dairy products) incorporation into our skeleton, hence providing strong bones and avoiding osteoporosis, especial during the later stages of our life. Additionally, sufficient vitamin D3 up-take strengthens the immune system and is very important to avoid the often occurring “winter-depression” in the northern countries. It is often also referred to as the “good mood vitamin”.


Cholecalciferol (vitamin D3) is found very seldom in our diet. One of the few natural sources where significant amounts of vitamin D3 is found are fatty fish (blue fish) liver oil. For e.g. cod liver oil, sardine oil and anchovy oil. Otherwise vitamin D3 is produced in our body by sun light, converting cholesterol into Cholecalciferol. Problem is, that modern societies lack direct sun exposure. Even kids prefer to stay indoors in front of their computer screens instead of playing outside with their friends. Finally when we do get the opportunity to enjoy direct sun exposure, we apply potent sun screens and blockers protecting us from skin cancer risk but also enabling the sun ray induced conversion of cholesterol in to vitamin D3. In consequence there is a generally observed vitamin D3 deficiency in our population. According to a recent study in Germany 91% of the women and 82% of the men do not have sufficient vitamin D3 supply. People with dark skins and the steadily growing portion of obese population are even worse off. Their natural vitamin D3 synthesis is not so efficient and often show severe deficiencies.


It is generally accepted in most countries of the world that our populations are vitamin D3 deficient. Thus most health organizations have issued intake recommendations for vitamin D3 in order to compensate our lack of direct sun light exposure.

In the US and the European Union (EU) the health authorities have set adequate intake levels of 400 to 600 IU (10-15 micrograms) per day for adults. For elderly higher levels of 400 – 800 IU (10-20 µg) have been recommended. Recently these recommended intakes are under discussion and it is believed they should be higher.

Experts strongly recommend that for everyone who does not have at least 45 min of direct sun exposure per week, should make sure they get enough vitamin D3 through their diet or adequate supplementation. An optimal vitamin D3 concentration in our blood, measured as “25(OH)D” lies at 30 ng/ml. To reach this level studies have indicated that the daily vitamin D3 intake should be about 800-1000 IU (20-25 µg).

Safety: Vitamin D3 (Cholecalciferol) is a fat soluble compound thus it does have a risk of accumulation in our body. A toxicity has however only been associated with very high doses of over 50.000 IU per day. The US and European Authorities (EFSA) have set a Tolerable Upper Intake Level for Vitamin D3 at 4,000 IU (100 µg) per day for adolescents and adults.

  IU (International Units) Microgram
Adequate intake levels for adolescents and adults 400 - 600 10 – 15 µg
Adequate intake levels for adolescents and adults 400 - 800 10 – 20 µg
Recommended Daily Intake (EFSA) 200 5 µg
Tolerable Upper Intake Level for Vitamin D3 4000 100 µg