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Neutrogena SPF 60: How can it get SPF60 with only 4.9% Titanium Dioxid and 4.7% Zinc Oxide?!
This seems to good to be true as I’ve never seen a sunscreen mineral supplier rating their formula more than 1% active / 2 SPF, so how can this formula be 3x that?
Are they using UV boosters? Alumina? Bisabolol?
Inactive Ingredients: Alumina, Arachidyl Alcohol, Arachidyl Glucoside, Ascorbic Acid (Vitamin C), Beeswax (Apis Mellifera), Behenyl Alcohol, Benzyl Alcohol, BHT, Bisabolol (L-Alpha), Butylene Glycol, Butyloctyl Salicylate, Cetyl Dimethicone, Dimethicone, Dimethicone PEG 8 Laurate, Dipotassium Glycyrrhizate (Licorice Root), Disodium EDTA, Ethylhexl Glycerin, Glyceryl Stearate, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate
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12 Replies
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Well what is the alumina for, do you think?
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1% active equals 2 SPF is an inaccurate and overly generalized claim. BASF makes an SPF calculator that is much more accurate. Also, regardless of all the calculations, it all rests on your testing. As long as they have test results that prove SPF 60, the rest is moot.
https://www.sunscreensimulator.basf.com/Sunscreen_Simulator/Login_show.action
You ask a great deal of questions regarding Mineral sunscreens. Out of curiosity, are you working for a manufacturer or trying this all at home? No offense, but the level of sophistication in training and equipment is how I gauge my advice. For instance, I would likely never give a Home Crafter too much information but simply say it is an area that requires appropriate assets (read her proper equipment, no shortcuts) and relevant experience in a technical setting.
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@Belassi. Yes I mentioned alumina, but I don’t know the specifics of how it’s work for sunscreen.
@Microformulation Personally I prefer to formulate in my Jacuzzi, but I do have 3 CMOs I work with on various projects as well. You would think big brands had professionals to make sure their mineral sunscreens are robust formulations, but turns out 75% of them don’t meet their SPF claims according to consumer report.
Thanks for the calculator, but not really useful for single filter formulas, e.g. entering 10% Zinc Oxide outputs SPF 4.6.
I’m doing systematic testing of different ZnO blends with different emulsification systems and potential UV boosters ATM, commencing outsourced in vitro testing for UV-B and A absorbance later this year post accelerated stability to to then potentially do a 10 panel in vivo test and get a daily moisturizer/sunscreen product on the market likely next year. I aim to announce all this at some point and thank ya’ll for the help.
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Ah yes. I made a daily moisturiser / sunscreen product last week at the seminar. It has ZnO of some pre dispersed form, two other UV absorbers, and a lot of advanced silicones.
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If you look it up, you’ll find that Alumina is frequently used as a filler in paints to be able to reduce the titanium dioxide level. I’m guessing someone found a way to keep it translucent. It’s not an approved sunscreen, so it’s on the inactive list, but I can’t think of any reason other than SPF boosting for it to be in a formula.
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Hi,
The formula got SPF 60+ because of combination of UV booster (technically they are sunscreens by the structure, not approved by FDA).
Regarding Alumina, it is typically as a coating of TiO2 because it helps in better dispersing the pigment and keeps the pigment itself stable.
Hope it helps!!!
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@cosmochem thanks, yes I’ve read it can work as a TiO2 coating, yet shouldn’t the pigment be stable without?
Anyways, suspect it’s not actually SPF60, Neutrogena seems to mainly care about putting whatever on their product that will sell best.
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Actually, I see a couple of tricks in this formula. One is the use of Bisabolol and Dipotassium Glycyrrhizate. Remember that SPF is determined using the redness of the skin as a proxy for sun damage, right? Well, if you use anti-irritants/anti-inflammatories, you can suppress the reddening reaction, and get a higher SPF score for your product. Of course, you don’t prevent any of the actual sun damage, so this is not something I’d recommend to an ethical sunscreen manufacturer.
The second trick is the presence of Butyloctyl Salicylate (HALLBRITE BHB) which may (or may not) be a SPF booster.
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cetyl dimethicone also helps the product form an even film, which (in principle at least) would help boost its SPF score
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@Bobzchemist yes this is likely part of how they got it, contrasting in-vitro with in-vivo SPF measurements would reveal this.
BTW to what extend do you think large companies measure the effects of each potential UV-booster added?
@Bill_Toge yep, but typically only up to 2x of %ZnO from what I’ve seen, so more of an SPF optimizer than booster?
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@Zink the quality of the film is a huge influence on SPF, don’t underestimate it!
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@Bill_Toge for in-vivo and in-vitro both? I’ve seen some DOW whitepapers where SPF double adding certain silicones. I’m actually waiting for samples of certyl dimethicone ATM, seems like a good bet in my formula although I’d be interested in exploring non-silicone options too.
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