Does sunscreen decrease vitamin D?

While sunscreens can decrease vitamin D production, they don’t appear to do so to a large extent. You need not completely forgo sunscreen in order to maintain a healthy vitamin D level. Sun exposure can be bolstered with vitamin D rich foods and supplements to attain sufficient levels.

Our evidence-based analysis features 17 unique references to scientific papers.

Written by Michael Hull
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Your body can produce vitamin D when the skin is exposed to ultraviolet B (UVB) rays[1] Yet it is these rays that sunscreens are designed to primarily block.[2] So will using sunscreen tank your vitamin D levels?

Vitamin D 101

Sunscreen and vitamin D production

Sunscreen can decrease vitamin D production under both controlled laboratory testing and real-world conditions.[3][4] This decrease is most notable if sunscreen is used consistently and properly[5][6][7] (i.e., when using a broad-spectrum sunscreen, the right sun protection factor (SPF), amount, and reapplication schedule).

Yet, the amount to which sunscreen decreases vitamin D production appears to be small — a counterintuitive finding.[8] How could this be? Two factors have been proposed as possible explanations.[8]

  1. People may not be appropriately using sunscreen during periods of sun exposure (i.e., incorrect type, amount, SPF, or application frequency). If not used correctly, UVB rays could easily reach areas of your skin where sunscreen is absent or where coverage is not sufficient enough.

  2. While sunscreen does a good job of blocking most UVB rays, it doesn’t entirely block them. A high amount of exposure to UVB rays is not required to kickstart vitamin D production in the skin. So, it’s possible that low amounts of UVB radiation could get past the sunscreen to initiate vitamin D creation.

One important caveat — studies to date have generally been conducted on people with less skin pigmentation (i.e., those with Fitzpatrick skin types 1–3). A different result may be seen in those with Fitzpatrick skin types 4–6.

While sunscreen can decrease your body's ability to produce vitamin D, in real-life usage scenarios it appears to only do so to a small degree.

How much sun do I need for vitamin D production?

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).[9][10] 

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.[11][12]

Fitzpatrick skin type scale

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.[13] 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 (37 degrees north and south of the equator).

💡 Tip: Calculate your safe UV exposure for a healthy vitamin D status

How much UV exposure you need to maximize your body's vitamin D production depends on a number of factors: time of year, location, skin type, weather conditions, and more. Fortunately, the Norwegian Institute for Air Research has developed a calculator, based on peer-reviewed research,[14][15][16][17] that takes these factors and more into account. This tool allows you to calculate UV exposure times to obtain optimal vitamin D synthesis without burning your skin.

You can try the easier simplified model or the more complex full model.

Bottom line

Sunscreen can decrease your body’s ability to produce vitamin D, but generally to a small degree.
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.
To increase your vitamin D levels, you can combine an appropriate amount of sun exposure to dietary sources of vitamin D and supplementation.

References

  1. ^ Bikle DD. Vitamin D metabolism and function in the skin. Mol Cell Endocrinol. (2011)
  2. ^ Antony R Young, Joël Claveau, Ana Beatris Rossi. Ultraviolet radiation and the skin: Photobiology and sunscreen photoprotection. J Am Acad Dermatol. (2017)
  3. ^ A Faurschou, et al. The relation between sunscreen layer thickness and vitamin D production after ultraviolet B exposure: a randomized clinical trial. Br J Dermatol. (2012)
  4. ^ Mantas Grigalavicius, Vladimir Iani, Asta Juzeniene. Layer Thickness of SPF 30 Sunscreen and Formation of Pre-vitamin D. Anticancer Res. (2016)
  5. ^ Libon F, et al. Sunscreens block cutaneous vitamin D production with only a minimal effect on circulating 25-hydroxyvitamin D. Arch Osteoporos. (2017)
  6. ^ Bibi Petersen, Hans Christian Wulf. Application of sunscreen--theory and reality. Photodermatol Photoimmunol Photomed. (Apr-Jun)
  7. ^ R E Neale, et al. The effect of sunscreen on vitamin D: a review. Br J Dermatol. (2019)
  8. ^ a b T Passeron, et al. Sunscreen photoprotection and vitamin D status. Br J Dermatol. (2019)
  9. ^ Barbara B Shih, et al. Fractional Sunburn Threshold UVR Doses Generate Equivalent Vitamin D and DNA Damage in Skin Types I-VI but with Epidermal DNA Damage Gradient Correlated to Skin Darkness. J Invest Dermatol. (2018)
  10. ^ Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, et al. Dietary Reference Intakes for Calcium and Vitamin D.
  11. ^ Ann R Webb, et al. Colour Counts: Sunlight and Skin Type as Drivers of Vitamin D Deficiency at UK Latitudes. Nutrients. (2018)
  12. ^ Ann R Webb, et al. Meeting Vitamin D Requirements in White Caucasians at UK Latitudes: Providing a Choice. Nutrients. (2018)
  13. ^ A R Webb, B R DeCosta, M F Holick. Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation. J Clin Endocrinol Metab. (1989)
  14. ^ Engelsen O, Kylling A. Fast simulation tool for ultraviolet radiation at the earth's surface. Opt Eng. (2005)
  15. ^ John C Dowdy, Robert M Sayre, Michael F Holick. Holick's rule and vitamin D from sunlight. J Steroid Biochem Mol Biol. (2010)
  16. ^ Vitaly Terushkin, et al. Estimated equivalency of vitamin D production from natural sun exposure versus oral vitamin D supplementation across seasons at two US latitudes. J Am Acad Dermatol. (2010)
  17. ^ Ann R Webb, Ola Engelsen. Calculated ultraviolet exposure levels for a healthy vitamin D status. Photochem Photobiol. (Nov-Dec)