Hello, I have two conflicting pages regarding the use of avobenzone as a sunscreen. Skin Biology states that it is unstable and degrades within 1 hour, but Paula's Choice states that it is stable for up to 72 hours.


The Paula's Choice page seems to have a lot of references to justify this assertion.

What do you guys think?

This message has been edited. Last edited by: SkinBiologyWebmaster,

My education was a BA in Chemistry and Mathematics and a PhD in Biochemistry.

Paula was trained as a Hairdresser.

Actually, avobenzone is worse than what is in our website. If you wonder when it totally will breakdown, then 3 hours is OK. But photochemists tell me it start to break down in seconds.

So for photoprotection, in 3 hours it is basically gone.

But the real issue is when does your skin and body start taking up the toxic breakdown products from avobenzone. Well, this would be in seconds to a few minutes for toxic products to enter your body.

From Wikipedia

Avobenzone is sensitive to the properties of the solvent, being relatively stable in polar protic solvents and unstable in nonpolar environments. Also, when it is irradiated with UVA light, it generates a triplet excited state in the keto form which can either cause the avobenzone to degrade or it can transfer energy to biological targets and cause deleterious effects.[3]

Avobenzone has been shown to degrade significantly in light, resulting in less protection over time.[4][5][6] The UV-A light in a day of sunlight in a temperate climate is sufficient to break down most of the compound. Data presented to the Food and Drug Administration by the Cosmetic, Toiletry and Fragrance Association indicates a -36% change in avobenzone's UV absorbance following one hour of exposure to sunlight.[7]

This message has been edited. Last edited by: Dr. Pickart,

Thank you for the clarification. I guess it is best to stick to mineral sunscreens.

It is really hard to find a decent moisturiser with sufficient UVA/UVB protection.

Dr. Pickart, could you please give me an idea of the titanium dioxide in your Day Cover? Also, does it have a blue tint to it? And what is the strength of the copper peptides inside?

This message has been edited. Last edited by: Idelle Musiek,

Also, please could you provide your comments on the following moisturiser with SPF15, as if it is good, I may purchase it:

Aqua, C12-15 Alkyl Benzoate (thickener), Titanium Dioxide (3,8%), Prunus Armeniaca (Apricot) Kernel Oil (non-fragrant emollient plant oil), Isononyl Isononanoate (skin conditioning agent), Propylene Glycol (slip agent), Zinc Oxide( 3%), Glyceryl Stearate, PEG-100 Stearate, Cetearyl Alcohol (thickening agents), Cyclopentasiloxane, Cyclohexasiloxane (silicone slip agents), Glycine Soja (Soybean) Sterols, Superoxide Dismutase (antioxidants), Tocopheryl Acetate (vitamin E/antioxidant), Tetrahexyldecyl Ascorbate (stabilized vitamin C/antioxidant), Unbiquinone (coenzyme Q10/antioxidant), Ceramide-2, Sodium Hyaluronate (skin-identical ingredients), Allantoin (anti-irritant), Dimethicone (silicone slip agent), Palmitoyl Oligopeptide (cell-communicating ingredient), Tribehenin (skin conditioning agent), Alumina, Aluminum Stearate (thickening/opacifying agents), VP/Eicosene Copolymer (film-forming agent), Polysorbate-20 (emulsifier), PEG-10 Rapeseed Sterol (skin conditioning agent), Polyhydroxystearic Acid, Xanthan Gum (thickeners), Disodium EDTA (chelating agent), Sorbitan Stearate (emulsifier), Ethylhexylglycerin (skin-conditioning agent), Hexylene Glycol (solvent), PEG-4 Laurate (emulsifier), Caprylyl Glycol, Phenoxyethanol, Iodopropynyl Butylcarbamate (preservatives).

I see no health problems with that product.

I don't know why the formulator used so many ingredients. Maybe they were just sitting on the lab bench.

When applied to the skin, would it make the skin have a blue tint?
And how strong is it compared to, for example, super cp serum, which I use almost every night?

I really really really want to reduce the appearance of aging with peptides, and after so much research, I still keep coming back to Day Cover as the best choice... but I really just want to make the most informed decision...

Really hope you can help me with the decision Dr. Pickart!

This message has been edited. Last edited by: Idelle Musiek,