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Is Your Sunscreen Doing More Harm Than Good?
By: Rhonda Allison
Posted: April 27, 2012, from the May 2012 issue of Skin Inc. magazine.
page 3 of 9
Topical sunscreens are broadly classified into two groups: chemical-absorbers and physical-blockers. Chemical-absorbers absorb UV rays while physical blockers reflect UV rays.5 There has long been much debate over chemical vs. physical blockers, primarily between skin care professionals and product manufacturers. In working with and seeking advice from various labs about sunscreen formulas, it’s been my experience that chemical-based formulas are typically cheaper and easier to produce, which may be why they are so widely available to the consumer. However, many chemical-absorbers provide less-than-adequate UV protection on their own and must be combined with other chemicals to do so. More importantly, research has shown that many of these ingredients do not protect against UVA rays, the highly dangerous rays that have the ability to penetrate the deeper layers of the skin and pose an even greater threat. This has been linked to increased melanoma rates, as well as the proliferation of photoaging by degrading collagen and elastin.12–14
SPF levels refer to UVB ray protection, but now the U.S. Food and Drug Administration (FDA) is requiring sunscreens to indicate on their labels whether they protect against UVA rays, as well. The new UVA/UVB protection labels will read “broad-spectrum SPF” and only those of SPF 15 and higher can claim to reduce the risk of skin cancer and photodamage. However, recommend that clients opt for at least an SPF of 30 because it provides 97% protection from UV damage.
Physical blockers have been shown to be more effective in protecting against both UVA and UVB rays.18 Titanium dioxide and zinc oxide are the two most commonly used blockers. These naturally occurring ingredients protect against the full UV spectrum; however, one of the major issues with naturally occurring blockers is the chalky cosmetic appearance and texture that is often associated with them.
Zinc oxide is an inorganic compound and an essential mineral for the body. It plays an important role in cell production, promotes healthy skin and hair, boosts the immune system and also provides broad-spectrum protection, which, in turn, helps reduce UVA-induced free radical production in the deeper layers of the skin. Zinc oxide is not absorbed by the skin; rather it sits on the skin’s surface, blocking both UVA and UVB rays.19
Titanium dioxide is derived from titanium and is a highly reflective chalky mineral. It is nonirritating, nonallergenic and noncomedogenic, which means it doesn’t cause or aggravate acne. The physical blocker is commonly used in sunscreens because it offers both UVA and UVB protection. Titanium is found in nature in minerals such as rutile, anatase and brookite.5, 20