white sunscreen on skin

Mineral sunscreens provide a convenient and reliable way of reducing your exposure to harmful UV radiation.  What are mineral sunscreens, what kinds of mineral sunscreens are available, and how do they work?

What are mineral sunscreens?

Most sunscreens sold today can be classified as either mineral sunscreen or chemical sunscreen.  Mineral sunscreens are topical skincare products that use mineral compounds to reduce the amount of UV radiation that hits the skin.  Mineral sunscreens come in many forms, including creams, lotions, sprays, and some SPF-containing makeup products. 

Protecting yourself against excess UV radiation from the sun is important, and this can be done by wearing broad-spectrum sunscreens that protect against both UVA and UVB rays, wearing UV-protective clothing, and minimizing sun exposure. 

Excess UV exposure is associated with accelerated photoaging and an increased risk of certain skin cancers.1  Excess UV exposure may be associated with other adverse health effects, including several eye conditions and photoimmunosuppression, which is when UV radiation leads to a diminished immune response.1,2 

Why mineral sunscreens?

There are different benefits for both chemical and mineral sunscreens.  For example, someone may choose to use a mineral sunscreen if they are sensitive to or allergic to the chemical filters used in chemical sunscreens.3 

Additionally, there are growing concerns about the potential effects of chemical UV filters on aquatic environments and ecosystems.  Residue from chemical sunscreens can get into lakes and oceans through direct exposures such as swimming, or as a result of runoff from showering and bathing.4 

A variety of studies suggest that some chemical filters may be associated with adverse effects in aquatic ecosystems; for example, oxybenzone has been linked to bleaching of coral reefs.5.6  More research is needed to confirm these findings, as well as determine whether these same findings would take place with lower, real-life concentrations of these chemical filters.

Two mineral UV filters sold in the United States are zinc oxide and titanium dioxide.  These mineral sunscreens work by reflecting UV radiation away from the skin when applied topically.7  These filters are well-studied, and the FDA recognizes both zinc oxide and titanium dioxide as safe, effective, and a good strategy for preventing adverse effects associated with UV radiation exposure.7,8,9

Zinc oxide versus titanium dioxide

Both zinc oxide and titanium dioxide offer high-strength UV protection with a relatively low risk of irritation; however, there are differences between these two filters.10 

Studies show that they are each more effective in different frequencies of UV radiation.  Zinc oxide appears to work best for lower-frequency UVA radiation, and titanium dioxide works best for higher-frequency UVB radiation.11  As a result, many commercial mineral sunscreens use both mineral filters to work together to help protect against a broad spectrum of UV radiation frequencies.11  There may also be differences in the stability of the two filters under UV radiation; however, more research is needed to confirm these differences and what they mean.12

What are the side effects of mineral sunscreens?

Mineral sunscreens are generally not associated with skin irritation or sensitivity, whereas chemical sunscreens may be associated with these effects in some people.3,13  However, mineral sunscreens are notorious for leaving a white cast on the skin after application, particularly for people with darker skin tones. This can decrease sunscreen adherence, and this ultimately can prevent people from getting the maximum protection with their sunscreen.

Some mineral sunscreens do not have this side effect; one way of avoiding white cast is using tinted sunscreens, which have pigment in them so they blend in with the skin tone.  Another way of avoiding or reducing this side effect is using mineral sunscreens that contain micronized forms of zinc oxide and titanium dioxide.11  However, the current evidence is inconclusive regarding their potential safety and whether they are absorbed through the skin, so some people choose to avoid sunscreens containing micronized mineral filters.11

It is important to seek medical help if you experience any side effects that you are concerned about when using any skincare product, including those containing mineral sunscreens.  Seek medical help immediately if you experience signs of an allergic reaction after using mineral sunscreens, such as chest tightness, hives, or swelling of the face, mouth, or throat.

This article is not medical advice, and it is not intended to prescribe, diagnose, or promote specific treatments for any condition.

References

  1. Gallagher, R.P., Lee, T.K. (2006). Adverse effects of ultraviolet radiation: a brief review. Progress in Biophysics and Molecular Biology 92(1): 119-131. Doi: 10.1016/j.pbiomolbio.2006.02.011
  2. Gibbs, N.K., Norval, M. (2013). Photoimmunosuppression: a brief overview. Photodermatol Photoimmunol Photomed 29(2): 57-64. Doi: 10.1111/phpp.12021
  3. Wong, T., Orton, D. (2011). Sunscreen allergy and its investigation. Clinics in Dermatology 29(3): 306-310. Doi: 10.1016/j.clindermatol.2010.11.002
  4. Diaz-Cruz, M.S., Barcelo, D. (2009). Chemical analysis and ecotoxicological effects of organic UV-absorbing compounds in aquatic ecosystems. TrAC Trends in Analytical Chemistry 28(6): 708-717. Doi: 10.1016/j.trac.2009.03.010
  5. Schneider, S.L., Lim, H.W. (2019). Review of environmental effects of oxybenzone and other sunscreen active ingredients. Journal of the American Academy of Dermatology 80(1): 266-271. Doi: 10.1016/j.jaad.2018.06.033.
  6. Pawlowski, S., Herzog, B., Sohn, M., et al (2020). EcoSun Pass: A tool to evaluate the ecofriendliness of UV filters used in sunscreen products. International Journal of Cosmetic Science 43(2): 201-210.
  7. Adamson, A.S., Shinkai, K. (2020, January). Systemic absorption of sunscreen: balancing benefits with unknown harms. JAMA 323(3): 223-224. Doi: 10.1001/jama.2019.20143.
  8. American Academy of Dermatology Association (2019, December 2). Is Sunscreen Safe? American Academy of Dermatology Association. Accessed 2021, July 13, from https://www.aad.org/public/everyday-care/sun-protection/sunscreen-patients/is-sunscreen-safe
  9. FDA Voices (2020, January 21). Shedding more light on sunscreen absorption. FDA. Accessed 2021, July 13, from https://www.fda.gov/news-events/fda-voices/shedding-more-light-sunscreen-absorption
  10. Dransfield, G.P. (2000). Inorganic Sunscreens. Radiation Protection Dosimetry 91(1-3): 271-273. Doi: 10.1093/oxfordjournals.rpd.a033216
  11. Smijs, T.G., Pavel, S. (2011). Titanium dioxide and zinc oxide nanoparticles in sunscreens: focus on their safety and effectiveness. Nanotechnol Sci Appl 4: 95-112. Doi: 10.2147/NSA.S19419
  12. Schneider, S.L., Lim, H.W. (2018). A review of inorganic UV filters zinc oxide and titanium dioxide. Photodermatology, photoimmunology & photomedicine 35(6): 442-446. Doi: 10.1111/phpp.12439
  13. Rai, R., Shanmuga, S.C., Srinivas, C.R. (2012). Update on Photoprotection. Indian J Dermatol 57(5): 335-342. Doi: 10.4103/0019-5154.100472
  14. Image by chezbeate from Pixabay 

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