How much sun do I need for vitamin D production?

    Researchedby:
    Kamal Patel
    Last Updated: October 13, 2024

    Generally speaking, 5 to 30 minutes of unprotected sun exposure to the hands, face, and arms at least three times a week between 11 a.m. and 3 p.m. is considered enough to keep blood vitamin D levels out of the deficient range (<30 nmol/L or <12 ng/mL).[1][2] image

    When determining how much sunlight you might need, there are two basic factors to consider:

    • The UV index (a measure of UV radiation intensity, from 0 to 11+)
    • Your Fitzpatrick skin type (a measure of how your skin responds to UV rays, from 1 to 6)

    When the UV index forecast in your area is 3 or higher, people with Fitzpatrick skin types 1 or 2 should keep unprotected sun exposure to less than 10 minutes; skin types 3 or 4, less than 15 minutes; and skin types 5 or 6, less than 30 minutes.[3][4]

    Fitzpatrick skin type scale

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    Keep in mind that longer periods of unprotected sun exposure don’t necessarily lead to higher vitamin D production, as the UVB rays will eventually cause the vitamin D in your skin to degrade to an inactive state.[5] This is a safety mechanism that helps protect your body against vitamin D toxicity.

    Don’t stop using sunscreen just to get your vitamin D levels up — a balance can be struck here. In addition to an appropriate dose of sun exposure, you can increase vitamin D through diet and supplementation. Diet and supplementation strategies will be particularly important for those who live in areas of low sun exposure or at latitudes where the sun’s rays may not be as potent for vitamin D production (greater than 37 degrees north and south of the equator).

    To summarize: Depending on the UV index and your skin type, 5–30 minutes of unprotected sun exposure to the hands, face, and arms at least three times a week between 11 a.m. and 3 p.m. should be enough to keep your vitamin D levels out of the deficient range. However, for people who live in northerly locations, have darker Fitzpatrick skin types, and/or lack sun exposure, supplementation may be required to maintain adequate vitamin D levels, as dietary sources of vitamin D tend to be inadequate.[10]