How to Calculate a Vitamin D3 Dose

Taking enough vitamin D3 is important for avoiding a wide range of diseases and health problems. Vitamin D deficiency has been linked to higher risks of heart disease, Osteoporosis and certain cancers. To calculate a vitamin D3 dose, doctors perform tests and take into account age, weight, lifestyle and geographic location. 

• Visit the doctor for a vitamin D test. This test measures how much of the vitamin is stored in your blood. For adults and children, optimal vitamin D levels generally fall between 50-80 ng/mL.   


• Examine your sun exposure. Vitamin D deficiency is more common in people who live in regions without adequate sunshine. Sun exposure allows the body to create vitamin D. If you do not live in a sunny region, regularly wear sunscreen, or cannot be outdoors for at least 15 minutes daily, you may need to take a vitamin D3 supplement. 


• Consider your dietary intake. Not many foods contain vitamin D. Some breakfast cereals and dairy products are fortified with the vitamin. Tuna and salmon are natural sources of vitamin D. If your diet is low in these foods, vitamin D3 supplementation is necessary.


• Take higher levels of D3 when deficient. Your multivitamin may contain 1,000 IU of vitamin D, which is generally considered adequate supplementation. Older people, people with darker skin and overweight individuals must generally take a higher vitamin D3 dose.


• Avoid extremely high doses of D3. Very high doses are associated with greater risks of falling and bone fractures in older people. It is generally best to take the vitamin in smaller amounts on a weekly or daily basis than overdo it in a single dose.