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Zinc Oxide and photoactivity with active ingredient from other skincare cosmetic product
Hi all,
I have been reading a lot about active ingredients in sunscreen and noticed that only TiO2 and ZnO are considered as GRASE category 1 in the FDA proposed ruling. When I looked into studies that have been done on these ingredients, it looks like they both exhibit photocatalytic when they are exposed to light. Although many products on the market are contained coated versions of the metal oxide to decrease their photocatalytic activity of them. Some product still uses the uncoated version of the metal oxide in the sunscreen. I am curious if anyone knows the potential risk of using sunscreen containing uncoated metal oxide and potential photocatalytic that can occur when such sunscreen is being used with other skincare/cosmetic products. I am especially interested in Zinc Oxide since I didn’t find much information on coated Zinc Oxide. I found this very interesting since I know the individual product needs to pass a certain test to established its photostability, but since we are using so many different products daily, will the photocatalytic activity also degrade/reacts with other ingredients from different product? Any insight would be helpful.
Thank you.
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4 Replies
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Simply put: uncoated zinc oxide SPF products will report lower SPF upon aging than coated ZnO used. TiO2 behaves similarly but not as much delta-SPF. Neither will react with/affect other ingredients as their chemical catalytic activity is smaller than, say, platinum. This is the conundrum we face: the organics are more stable (when formulated correctly), easier to work with, more ubiquitous, have better sensorial properties and more supply sources; yet FDA and the coral reef watchers make using them a difficult decision.
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chemicalmatt said:Simply put: uncoated zinc oxide SPF products will report lower SPF upon aging than coated ZnO used. TiO2 behaves similarly but not as much delta-SPF. Neither will react with/affect other ingredients as their chemical catalytic activity is smaller than, say, platinum. This is the conundrum we face: the organics are more stable (when formulated correctly), easier to work with, more ubiquitous, have better sensorial properties and more supply sources; yet FDA and the coral reef watchers make using them a difficult decision.
Thanks for the explanation, with coated zinc oxide, what kind of coating are they using? Are these coatings good for the environment?
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sunscreen-grade titanium and zinc oxides are coated with a variety of materials, depending on the manufacturer: silicones, jojoba esters, myristoyl myristate, lauroyl lysine, stearic acid… basically, anything hydrophobic that’s solid near room temperature
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Every mineral sunscreen contains zinc oxide as it forms a physical barrier on the skin to protect it from sun damage. But few of them cause allergy to zinc oxide that cause irritation and dryness. So, it’s better to do a patch test and to know more visit [url = https://blogbin.site/mineralnchemicaldiff/%5D allergic to mineral sunscreen [/url]
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