For all of my health conscious Bay Area patients, reading a bottle of sunscreen can be scary. It is just like reading the ingredients on the back of ice cream. If it doesn’t say things like “sugar” and “milk” you worry about putting it into your body. So what is all of the stuff on the back of the sunscreen bottle mean? And what do we need?
There are two general groups of sunscreens. CHEMICAL BLOCKING agents, use chemicals to block the sun rays. Examples of UVA filters are oxybenzone, Parsol 1789, and Mexoryl SX. Examples of UVB filters are PABA, Padimate-O, Cinoxate, Octinoxate, Ensulizole. PHYSICAL BLOCKING agents are compounds you put on your skin which physically block the sun rays, and are good for both UVA and UVB.
Some more information on common ingredients:
OXYBENZONE:
- Synthetic estrogen (Controversy: A 2002 study indicated it interferes with hormone levels- Controversies exist for this study as it was done at very high doses and in rats- not a good model. a 2004 study showed it didn’t cause significant hormone disruption in humans.)
- FDA approved after exhaustinve review, and approved by the Skin Cancer Foundation Photobiology Committee
- Been in US sunscreens since the early 1980s
- Does not accumulate in the body (So significant build up can’t happen)
RETINYL PALMITATE
- Vitamin A form stored in the skin
- Controversy: Some studies indicated when exposed to UV radiation, it generated free radicals. (In the skin antioxidants like Vitamin C and E are thought to neutralize free radicals) Free radicals are thought to cause issues with DNA and lead to cancer. The study which showed this is an unpublished older study in mice.
- Retinoids are commonly prescribed by MDs to improve skin health, and oral retinoids are given to help prevent skin cancer in people at high risk for skin cancer.
NANOPARTICLES: (FANCY WAY OF SAYING PHYSICAL BLOCKING SUNSCREENS)
- Titanium dioxide and Zinc oxide
- Most protective broad spectrum ingredients
- Used to be that thick white stuff you would put on your nose. But then with advances in technology, they were able to make the particles smaller, “micronizing” so that it appears clear when you put it on.
- Multiple studies have shown that nanoparticles do NOT penentrate living skin.
- These are my favorite- particularly for women who are pregnant, breastfeeding, and kids. Maybe I have lived in California too long, but I like that they are physical blocking agents, not chemicals.
- This is the base of the Skinceuticals and Obagi brands.