Chemical vs. Physical sunscreens

[TwoBees]

Let's put aside the health debate for a sec. Which type of sunscreen PROTECTS from UVA and UVA rays better, and why?

[Kindra178]

It's my understanding that a physical blocker is better because it lasts longer. Put another way, both kinds of sunscreen/block "work," but physical blocks last longer without the need for as frequent re-application.

[georgiegirl]

Im highly impressed with physical blockers. We were at disney a few weeks ago and used trukid sunny days SPF 30 and we came home without a drop of color on us. I applied in the morning and then again in the afternoon. It was sunny with highs in the high 80s, low 90s. DS refused to wear a hat often , and we did the badger stick on his face, and he's still white a ever. We are all quite fair and I've never had a sunscreen protect us so well.

[brittone2]

I don't think you can separate out the "health" effects from "protection." EWG does look at how well each sunscreen balances UVA and UVB protection as part of its (not perfect, but helpful) scoring system.

Some chemical sunscreens become unstable as they degrade in the sun, leaving you without UVA protection. Some folks will tell you this is by design (this is how they work more or less, and you can get around it by reapplying often). Physical blocks work differently, by scattering the incoming UV rays.

Sunburn comes from UVB rays. But UVA rays contribute substantially to skin cancer. Some of the concern is that there are quite a number of products out there that offer little to no UVA protection. People feel their kids are ok because they aren't getting burned, but they are still getting UVA exposure. At one point I think ewg said 1 in 8 sunscreens didn't offer any UVA protection.

EWG also looks at things like retinyl palmitate as an ingredient. It is fairly common but there is a concern that it may actually increase the risk of developing melanoma.

In the past few days I've seen comments here saying their primary concern is their child not burning, and I get that, but there is more to it than simply not burning or endocrine disruption concerns.

IMO, the health effects are tied to the "protection" factor, even if we aren't talking about endocrine disruption, etc.

EWG has some interesting quotes here:
http://breakingnews.ewg.org/2011sunscreen/sunscreens-exposed/health-agencies-question-sunscreen-efficacy/

some background here:
http://breakingnews.ewg.org/2011sunscreen/sunscreens-exposed/sunscreen-and-skin-cancer/

retinyl palmitate and melanoma concerns:
http://www.ewg.org/release/nih-panel-links-vitamin-sunscreen-skin-tumors

eta: we aim for a non nanosized physical block, or at least a physical vs. chemical block.