encapsulated sun filters

[Dfontaine]

Ok, I finally did it. I've started using UV filters is some of my producds.
I'm currently using Oxybenzone, Micronized zinc Oxide and on a small scale, Micronized titanium dioxide. The Max spf I'm going for is 15-20.

In my journey of research, I've found that certain UV filtering agents are absorbed into the skin to the point where they are useless after a few hours. The absorbtion rate is different for each product depending on the % in the formulation and absorbtion rate is also affected by the vehicle it's in (ie the cream)Then I started reading about encapsulated sun filters - products mostly found in Europe.

I have no idea what they are. I know for example that Titanium dioxide is insoluble in water or oil however dispersable in water. Does that make it encapsulated? So If I use it can I call it encapsulated? Not that I would, I just would like to know if anyone has any info on this.

Thanks

[orangehrzn]

Zinc and Titanium are not absorbed.

The chemical filters supposedly have to saturate the epidermis to do their thing. I think the encapsulation applies to the chemical ones only, it supposedly reduces their irritation potential.

The physical zinc and titanium could be coated with dimethicone. In the case of titanium that prevents it from reaction with skin because there was some study showing uncoated micronized titanium to create free radicals. The coating supposedly prevents that. There wasn't a similar study for micronized zinc so it is considered safer than titanim.

[Dfontaine]

I'll go and try to find the articles I looked at that show at least some UV protectors are very much absorbed (I believe titanium dioxide was one of them) and though in small amounts, show up in urine samples. I Think Zinc oxide also did. The test didn't say if 100% was added to the skin or if they used the FDA approved dose, however it was clear that some UV protectors do enter the blood stream.

Thanks for the info on the free radical stuff. Interesting.

It's an interesting field - one that I've only begun to touch on, but I've read studies were various ingredients boost UV protection (for example I think it's green tea extract that boosts the effectiveness of Zinc based UV blockers) yet the government guide lines for what % of what ingredient provides what "SPF" do not include any of these studies. Say if you use 6% micronized zinc it will give you an spf of 6 - but what about if you use 3% green tea extract with it?

I think they come up with the SPF factor by how long it protects so maybe after 1 hour it's spf 70 and after 4 hours it's 4. It's also dependant on how much you put on - for example, a light spread lotion or gel verses a heavy cream could drastically affect the protection. Point being that, sure, if you use the half an ounce of cream on your face, the spf will be 30 - however if you only use 3 grams it will only be 2.

There are recommendations by the FDA on how much of a product you need for protection and it's much more than the average person puts on their face.