Experts haven’t agreed on a number that defines a low vitamin D level. For most healthy people, the Office of Dietary Supplements states that a vitamin D serum (blood) level below 20 nanograms per milliliter (ng/mL) or 50 nanomoles per liter (nmol/L) may not be adequate for bone and overall health.

Other organizations define a vitamin D insufficiency as 12 to 19 ng/mL (30 to 47.4 nmol/L) and a vitamin D deficiency as less than 12 ng/mL.

An optimal vitamin D level may vary depending on personal factors such as age or race. This makes it hard to definitively say what’s “right” for any group of people.

Your doctor can help determine whether your vitamin D level may be low based on your personal characteristics and medical history and recommend steps you can take to increase it.

Like optimal vitamin D levels, experts haven’t agreed on an optimal daily intake of vitamin D. The amount you need may depend on your age and other factors.

The following table shows the Office of Dietary Supplements’ general guidelines in micrograms (mcg) or international units (IU).

AgeDaily amount
0 to 12 months10 mcg or 400 IU
1 to 13 years15 mcg or 600 IU
14 to 18 years15 mcg or 600 IU
19 to 50 years15 mcg or 600 IU
51 to 70 years15 mcg or 600 IU
over 70 years20 mcg or 800 IU

Again, these are general guidelines and the exact amount necessary for optimal health may differ between individuals based on many factors. The recommended daily amount may also be higher if you’re trying to manage a vitamin D deficiency.

Ask your doctor how much vitamin D you may need daily.

You may be able to increase your vitamin D levels in the following ways:

Talk with a healthcare professional before increasing your vitamin D intake. They can help you create a safe, appropriate plan.