#1: Is All Sunscreen Created Equal?
Current general consensus is in favor of mineral-based sunscreens containing zinc oxide or titanium dioxide as active ingredients. Mineral-based sunscreens are the best physical blockers of UV light, causing light reflection from the skin. While chemical sunscreens do offer broad-spectrum UV coverage, there has been increasing concern regarding the effects of such chemicals on human health and the environment. In one study (Matta et al), 6 active ingredients found in many chemical sunscreens—avobenzone, oxybenzone, octocrylene, homosalata, octisalate and octinocate—were found to be systemically absorbed with topical use, with blood concentrations surpassing the FDA safety threshold. Furthermore, due to concerns regarding coral reef bleaching, Hawaii will be banning on sunscreen containing oxybenzone and octinoxate effective January 2021.
Take-away: Always check active ingredients and choose mineral-based sunscreen over chemical sunscreens.
#2: Should I Get a “Base Tan” Before My Vacation to Protect My Skin from Burning?
PSA: there is no such thing as a “healthy tan”!
It is well documented that UV light exposure, both natural and artificial, are the number one contributing risk factor to the development of skin cancer. Even with this knowledge, I still find a common misconception among patients is that as long as you don’t get a sunburn, then you are in the clear. Unfortunately, regardless of whether the skin is burned or tanned, UV light exposure is affecting our cells on the level of the genome- inducing DNA damage in the form of gene mutation and pro-inflammation affecting the skin’s immune system. The cumulative effect of these mutations results in photocarcinogenesis (skin cancer) and photoaging. Worried about Vitamin D deficiency? No worries, this can be addressed by oral supplementation as directed by your primary care doctor.
Take-away: SUN PROTECTION (SPF30+), EVERYDAY! This should be used in adjunct with appropriate clothing including hats and seeking shade when appropriate.
#3: UVA? UVB? Which Type of UV Protection is Best?
There are three wavelengths of UV light absorbed by the skin—UVC, UVB, and UVA. The difference in classification is based on the wavelength of light, with UVA being the longest ranging from 315-400nm. The type of UV absorption dictates its consequences, as short/ long-term effects are wavelength dependent. A pneumonic that has carried with me since PA school is “B” is “Bad”. UVB is absorbed by DNA in the skin which causes mutations and changes that lead to skin cancer. Additionally, shorter wavelengths are more likely to induce sunburn. However, UVA and even visible light can still produce local effects that directly and indirectly lead to DNA damage, although with lower efficacy.
Take-away: Although differences exist, the types of UV light should not be considered as discrete entities. Choose sunscreen with broad/ full-spectrum UVA/UVB protection.