я просто как то год назад занялась выяснением какие именно вещества являюся защитными от UVB и UVA.
Выяснилось что только три официально утверждены как действительно защищающие, это Zinc Oxide, Titanium dioxide, , avobenzone (Parsol 1789 or methoxydibenzoylmethane) and Mexoryl SX.
Все остальные официально не утверждены и защитными их считает только производить так как запретов тоже никаких нет.
А недавно вот такая информация промелькнула, вроде считается что Zinc Oxide самый лучший:
Zinc oxide, titanium dioxide, free radical formation, and DNA damage
From Maier, Schauberger, Brunnhofer, and Honigsmann, Change of Ultraviolet Absorbance of Sunscreens by Exposure to Solar-Simulated Radiation, J Invest Dermatol 2001 117:256-262
This paper examined 16 European sunscreens for photostability and found that most of them were not photostable, some at low to moderate simulated doses of solar radiation that would be realistic for many skin types. The photostability they observed seemed not to depend on active ingredients but was more highly correlated with polarity of the solvent (which is often overlooked as unimportant. It isn't!).
But, it also goes on to describe some other issues in changes to UV screens upon UV radiation.
Here is a key paragraph that provides another
reason as to why ZnO (silicone coated) is preferred:
"Until recently, microfine inorganic filters seemed
to be ideal ingredients to provide broad-spectrum
UV protection and to maintain photostability of
sunscreens (Anderson et al, 1997, Mitchnic et al,
1999). Danford et al (1997), however, showed that
microfine ZnO and TiO2 not only scattered and
reflected but effectively absorbed UV radiation
thus initiating reactive oxygen species formation
and catalyzing DNA damage. For uncoated ZnO
and for both coated and uncoated TiO2, Mitchnick
et al (1999) measured a significant photocatalytic
potential (ZnO << TiO2), whereas the photoreactivity
of coated microfine ZnO appeared to be negligible."
Note: If the particles stay in the outer layers of the strateum corneum, this is not an issue. But, if they travel deeper, it is. There are conflicting reports as to how deeply microfine mineral blocks penetrate. The vehicle is big factor for depth of penetration, although most recent sunscreens are poorly penetrating emulsions by design. For now it appears that silicone coated microfine ZnO (Z-Cote HP-1, which is probably the most commonly used microfine ZnO) may be the safest and most reliable UV screen.
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В общем я на всякий случай сейчас покупаю санскрины только с этими веществами ...ибо солнце у нас тут зверское одной ромашкой не спасешся...печальный опыт был
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