Does coating sunscreen nano-particles get rid of all side effects?

I've read in many articles that nano titanium dioxide and zinc oxide are photocatalysts, meaning they can form free radicals under influence of UV light. The definition of what would be considered nano varies between countries, we look at the coated clumped together particles, but in Europe they look at the particles seperately. I've seen many "non-nano" sunscreens labeled as "nano" in Europe. So I would rather choose a sunscreen with coated particles, than a "non-nano" sunscreen that isn't coated, not knowing if it would be considered nano under stricter regulations.

I was wondering, coating the particles reduces the photocatalytic capacity, but to what extend? Is it for example 90% or less? How stable are these coatings? Are the particles photostable during a whole day? And are there possible other negative side effects from these sunscreen ingredients?
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Comments

  • Honestly, I don't know Peter. I haven't seen any research that would specifically answer your questions about sunscreen particle coating. 
  • I've found an article from Europe: Collipa Opinion on Titanium Dioxide, which is the organisation which approves sunscreens in Europe.

    "The photocatalytic activity can be greatly reduced by coating the surface with various compounds. For example, the photo-catalytic activity of titanium dioxide when coated with silicon dioxide and alumina to the extent of 3.5% of the weight of titanium dioxide will reduce photo-catalysis to 1% of that found in the uncoated titanium dioxide. Although a few studies showing coating stability have been provided, it is important to know whether this, for example, could lead to the release of aluminium ions from alumina that may be present after the coating process and which may dissolve in the final formulation. It is less clear how stable the coatings are in final formulations. The photocatalytic activity data, measured in formulations, indicate that either some of the materials were not completely coated, or some of the coatings were not stable in the formulations. SCCS has considered acceptable an arbitrary level of up to 10% photocatalytic activity of a coated or doped nanomaterial, measured in terms of % to a reference standard"...."It is therefore possible that a trace amount of nanoparticles may remain embedded in stratum corneum, in hair follicles, and/or sweat glands, potentially over several days after skin application of a product and washing off"..."Three other rutile coated nanomaterials also have comparatively lower but still significant levels of photocatalytic activity (S75-C, S75-D, 4 S75-E)"..."further investigations over longer post-application periods taking into account the potential photocatalytic activity post-application, whilst allowing for appropriate lag-time and using realistic application scenarios may be necessary to ascertain that they do not pose a risk due to photocatalytic activity."

    There's also a table with the remaining photo-catalytic activity after coating, it varies from 0.3% to 11.8%. Trimethoxycaprylylsilane still has 10% activity, alumina/stearate around 7% and the lowest with alumina/silicones 0.3-0.7%
  • Nice work!
  • Why not non-nano non-coated sunscreens?
  • Well there not that many real non nano sunscreens, and besides some companies are not completely honest about what they're using. I would rather use a coated nano sunscreen that doesn't leave a white cast, then a sunscreen with physical filters that are not coated without knowing for sure if there are nano particles present.

    A sunscreen may be considered non-nano if more than 50% of the particles are larger than 100nm. So theoretically still 49% could be in the nano-range.
  • edited October 2016
    @Peter ;Thanks for raising the awareness about coated ZnO & TiO2.

    From my limited knowledge, coated zinc/titanium / micro sizing is proprietary currently... so not too much research out them for us lay people to peruse :( The technology differs a lot from company to company. One of the companies that were successful with this technology, Invisible Zinc was a local Australian company but bought over by larger USA company now. IMHO, it's the best Zinc sunscreen that i can buy here currently.

    Size of Physical Blockers (as an example)

    • Zinc oxide size: 200-1000 nm

    • Zinc Oxide, Micronized: 30-55nm

    • Zinc Oxide, Micronized & Coated: 86nm

    • Titanium oxide: 200-250 nm

    • Titanium Dioxide, Micronized: 15 nm


    Noted that due to TiO2 smaller size, it has been used more frequently in makeup compatible primers / bb cream / moisturisers etc as opposed to ZnO. UVA protection by TiO2 isn't as good as ZnO though. We have to be careful as consumers here in AU to lookout for "broad-spectrum" protection since PPD isn't rated on our sunscreens.

    The other point is ZnO is toxic if "breathed", Yet, i have a Japanese sunscreen spray that contains ZnO. peculiar indeed.
  • Does the Invisible Zinc sunscreen have a strong white cast?
  • escherichia  To answer your question plainly. Yes. 

    I overcome it with a layer of BB cream. No issue. I am Mac NC15, so very fair but i still find the sunscreen too white for my skin.

  • Thanks! I guess that is out for me then. ><
  • edited October 2016
    escherichia  to be fair. ALL the mineral sunscreens will give you a white cast.

    You want to consider Babo Botanicals.The white cast is really minimal. I have worn it out (after 2pm) and it seem to have protected me well enough.  http://loveneedwant.wixsite.com/blog/single-post/2016/09/24/Review-Babo-Botanicals-SPF40-Daily-Sheer-For-Face-Sunscreen

    Before
    image

    After 2 layers:
    image
  • edited October 2016

    Australia's Therapeutic Goods Administration (TGA) website (the TGA is the Australian equivalent of US's FDA) has rigorously studied nano particles in sunscreen. They conducted an updated review of the scientific literature in relation to the use of nanoparticulate zinc oxide and titanium dioxide in sunscreens  and concluded that:

    • Several in vitro and in vivo studies using both animal and human skin have shown that these nanoparticles do not penetrate the underlying layers of skin, with penetration limited to the stratum corneum. This suggests that systemic absorption is unlikely.
    • In conclusion, on current evidence, neither TiO2 nor ZnO nanoparticles are likely to cause harm when used as ingredients in sunscreens.

    For the full TGA report on the safety of Titanium and Zinc, please use this link: https://www.tga.gov.au/literature-review-safety-titanium-dioxide-and-zinc-oxide-nanoparticles-sunscreens. ;The report confirms that all research thus far shows these ingredients to be safe and the best protection from the sun.

    I refer to the Cytotoxicity and genotoxicity section that even uncoated Nano-TiO2 is not cytotoxic or genotoxic. 

    The TGA have paid such close attention to this topic because Australia is the perennial front runner in cases of skin cancer per capita. They want to know what works to help prevent skin cancer but are also concerned with safety.

    The Cancer Council Australia reported further in early 2014 that a recent Australian study found that human immune cells (macrophages) exposed to zinc oxide nanoparticles effectively absorbed the nanoparticles and broke them down.

    So, zinc oxide and titanium dioxide nanoparticles aren't absorbed through the skin into the bloodstream and, in the event that they do get into the bloodstream (for zinc oxide at least), the body's immune system can deal with them effectively.

    The overall conclusion is that there's no known health risk from these nanoparticles and you can safely use sunscreens that contain them.

  • @preciousia

    The articles do say that nano titanium dioxide in both rutile and anatase form are photocatalysts, however because they concluded the penetration is limited to the stratum corneum, they say it doesn't do any harm. That's why inhaling the particles is cytotoxic and genotoxic. Titanium dioxide has more photocatalytic activity and zinc oxide has a higher penetration risk, so for both of them a stable coating would be beneficial. UV-radiation will cause free radicals deep in your skin, but free radical formation with particles that might end up deeper in skin after very long daily usage doesn't sound very good to me either. You have to realise there are almost no studies which have investigated the effect of using sunscreen on human skin every day for several years. Especially the long term studies on impaired skin are scarce. So it can be concluded that physical filters are safe and okay to use in cream form, but I do think there still is some uncertainty and we might find better alternatives in the future with the first 8 sunscreens I mentioned in my post being good options.  

  • edited October 2016
    My dermatologist's private label sunscreen is SPF50+, tinted (perfect Colour) and it is pure mineral. No white cast, it doubles as a light BB cream/ makeup primer/base. Have noted many dermatologist recommending pure mineral sunscreen.

    Agree that when applied, there is no risk. Inhaled is another matter! Due to titanium dioxide smaller size perhaps, I do notice it is present in many makeup powders eg Bare Minerals foundation ... If inhaled accidentally it is not good. I dare dare bare minerals titanium is proper uncoated too? Need to double check.

    I am positive my sunscreen spray contains zinc oxide (unclear if coated). Can't read Japanese. At least THA concluded that the body is able to break down Zinc Oxide if it is absorbed.

    I believe many people here in Australua are living examples of using the mineral sunscreens everday for many years. I myself have been using mineral sunscreens (doctor's private label) for over 10 years.

    Those who yacht /boating for a hobby/livelihood use invisible Zinc or even Zincstic. I'll find out what works from those in the Australian sun more than me.

    The TGA have been studying this issue of nano particles for over 10 years as well since 2006. Will check to see if all 8 chemicals from your list are approved here in Australia, eg Tinosorb is not approved in USA but approved in Australia. Tinosorb absorbs heat which is a concern for my pigmentation.
  • @preciousia

    As far as I know most make up powders use pigment grade titanium dioxide, meaning non nano. But there are also powders where they list titanium dioxide [nano]. I haven't seen many studies where they follow a large group of persons for several years, most studies only last for 2 weeks to 6 months.

    Unfortunately we don't have that many options of fragrance free physical sunscreens in Europe. Maybe Tinosorb M is the best hybrid, it absorbs some radiation and scatters/reflects some.

  • yes i did notice that Europe has more chemical sunscreens.

    @Peter If you like, i can find an Australian pharmacy that will ship overseas. (after i tried and tested their products of course)

    tbh. mineral is best. no heat = less problems for pigmentation.

    and the ones i use are fragrance free. There is a website i use that sells many "healthy" sunscreens. They deliver worldwide and postage is free if you buy over USD40, their prices are really fair and i have been a big sucker buying many times from them. Quite a few of my skincare products come from this website recently. You can also buy the Innisfree sunscreen from them.

    I just click buy on Curel. It's going to be a trying summer, out in the heat during peak hours with the family on vacation. :( boy oh boy. i am going to be testing 7 sunscreen samples + 2 new ones on the way + 10 sunscreens i already own. In search of the HG sunscreen.
  • edited October 2016
    What are your thoughts on the "safety" of this product



    mineral powder for sunscreen. first of all, is powder adequate coverage? 


    ingredients:

    Gluten-free: Yes
    Paraben-free: Yes
    Unscented: Yes

    • Shade: Fair

      • Active Ingredients: Titanium Dioxide 23.9%; Zinc Oxide 24.1%

      • Inactive Ingredients:

        • Fair: Mica, Dimethicone/Vinyl Dimethicone Crosspolymer, Corallina Officinalis Extract, Methicone, Dimethicone, Calcium Silicate, Triethoxycaprylylsilane, Sodium Sulfate, Laureth-4, Iron Oxides (CI77491, CI 77492, CI 77499)

    • Shade: Medium

      • Active Ingredients: Titanium Dioxide 23.9%; Zinc Oxide 24.1%

      • Inactive Ingredients:

        • Mica, Dimethicone/Vinyl Dimethicone Crosspolymer, Algae Extract, Mannitol, Methicone, Dimethicone, Calcium Silicate, Triethoxycaprylylsilane, Sodium Sulfate, Laureth-4, Diatomeaceous Earth, Zinc Sulfate, Iron Oxides (CI 77491, CI 77492, CI 77499)

    • Shade: Tan

      • Active Ingredients: Titanium Dioxide 23.9%; Zinc Oxide 24.1%

      • Inactive Ingredients:

        • Mica, Dimethicone/Vinyl Dimethicone Crosspolymer, Algae Extract, Mannitol, Methicone, Dimethicone, Calcium Silicate, Triethoxycaprylylsilane, Sodium Sulfate, Laureth-4, Diatomeaceous Earth, Zinc Sulfate, Iron Oxides (CI 77491, CI 77492, CI 77499)

    • Shade: Deep

      • Active Ingredients: Titanium Dioxide 23.9%; Zinc Oxide 24.1%

      • Inactive Ingredients:

        • Mica, Dimethicone/Vinyl Dimethicone Crosspolymer, Algae Extract, Mannitol, Methicone, Dimethicone, Calcium Silicate, Triethoxycaprylylsilane, Sodium Sulfate, Laureth-4, Diatomaceous Earth, Zinc Sulfate, Chromium Oxide Greens (CI 77288), Iron Oxides (CI 77491, CI 77492, CI 77499)

  • My understanding is that owder alone does not an adequate coverage.  
  • edited October 2016
    @RandyS Yes... that's what your podcast said! I'm been studying up TBB. I don't see how they "hold" or form a barrier... so easy to rub off. It's $60+ for the SPF50+ .... good money in suncare that are makeup compatible
  • @preciousia
    I've ordered some products from england and america before, but most of the times its hard. In The Netherlands we pay by iDeal, most other countries only except visa or paypal. And after paying a lot for shipping and the product itself, most of the times I was disappointed, because it left a white cast, was drying or had an unpleasant texture. The Coola Mat SPF30 tinted, was almost perfect, no white cast, easy to apply, great ingredients. But the texture makes it impossible to apply enough, and it was very drying to my skin. 

    The powders are safe and don't contain irritants. Although for UV-protection it doesn't work. I don't know where I've seen it, but there was a study where they measured the UV-protection from powders and foundations. With normal application a consumer would end up with a SPF of between 2-3, from powder/foundations with SPF30. So if you have oily skin it's great for mattifying, but for sun protection you need a sunscreen. The study even found some moisturizers with SPF didn't have the right texture to form a sufficient film thickness on the skin, while with products formulated as a sunscreen certain ingredients may help to get sufficient film forming (like Aluminum Hydroxide and polymers for example). 
  • edited October 2016

    I must have been a sucker. i bought this Zinc oxide powder from Japan

    image

    • active ingredients: Zinc oxide + Octinoxate
    • Takes away shine
    • Hides pores, imperfections
    • Protects like a micro-velvet veil.
    • Recommended in the Japanese blog ratzillacosme.com (full ingredients on the link)
    • SPF50+/PA++++
    • Ingredients include
      • 92% Botanical minerals and moisturizer
      • Argan oil (alganiaspinosa core)
      • Vitamin C (cinnamyl Ascorbic tetrahexildecane acid)
      • Amino acids (lauroyl lysine)
      • Flower extracts of five species (multiflora fruit extract, Chamomile flowers extract, Calendula officinalis flower extract, arnica flower extract-capillaris flower extract)
      • 13 different mineral ingredients
    • Protects the skin against moisture loss.
    • Sweat resistant
    • Paraben and Alcohol Free
    • Made in Japan.
  • edited October 2016
    @Peter

    I'll be happy to guinea pig and do swatch test and feedback on the texture / if sticky / white cast etc of all the sunscreens i will be trying.

    I have been using my dermatologist's sunscreen for over 10 years. One brand. So there's a lot of sunscreen to try but only one face. If you really want to try something. i will be happy to mail you a sachet in the post, a sample of the sunscreen sealed it in a mylar bag :) With compliments. If you like it, you can get it from anywhere, if not. no worries. i understand what it's like to buy a whole bottle and not like the product (kind of what i am doing with my Moogoo... dreading)

    TBH most mineral sunscreens are awful in texture, white cast! Nothing. not even the "invisible" ones are really invisible. They "reflect". Some girls who are really fussy have special "day foundation" and "night foundation"... erm the diff is no flashbacks when camwhoring.

    Coola is a very good brand. (i never tried) It really depends on what you define as white cast. If you see the Babo Botanicals swatch i did, is that acceptable?  I am pretty fair. MAC NC15. So it's easy when buying makeup, i'm usually the lightest shade, and sometimes the lightest shade is too dark for me :(

    I found moisturisers with sunscreen good for layering but NOT good as the main source of sunscreen.

    My dermatologist always say.. get the sunscreen. not the multi-purpose product.

    i refer to Almay new marketing campaign, digging at the Korean 10 step routine.

    no way i am using their product for all my needs. Jack of all trades...

  • Preciousia! 

    Thank you so much! I don't know why but now that I can access your blog, I can't see the photos. But I shall look out for the Curel and Babo Botanicals. I do like the Badger sunscreen that I got, just that the white cast is horrific. If I apply a very thin layer (gotta forget about the 2mg/cm2) I kinda can get away with it though. BUT, the quest for the perfect sunscreen never stops. And just like Peter, I'm sick of spending so much $ ($60 is a lot to me) to order something that I can't/hate to use it. Sigh.
  • edited October 2016
    Maybe Wix is telling me i have used up my "free" bandwidth, i have been having issues with speed with the "free account" i have. 

    doh!

    need to pay them.... 


    Don't get Curel yet... i have one on the way... i'll test it and do a patch test to share so you can see for sure if the color /white cast is ok.

    Badger is not a makeup friendly sunscreen but a very good sunscreen.

    anyway .. what s 2mg/cm2? they calculate 1tsp (5ml) for the neck and face... for the death of me i can't even use up 1/2 tsp let alone 1 tsp! maybe i am using 1/4tsp at best.
    my face is smaller than the 1 tsp they calculate (average man's face) so how would we calculate the quantity used? face size in cm2? hehe. this is too technical for me.

    escherichia yes i totally agree with wasting money on products you don't want.. and can't bear to toss. Fortunately i did a swap with someone in Sydney for the Moogoo sunscreen (she didn't like it) and there were no testers in the store, no reviews either. I swapped it with something i don't use. As it came in an airless bottle, i was ok with it. normally i am a germaphobic. Cost only AUD$3 to mail a sample sachet. Would be happy to share... anyways. Babo is only USD17 a tube. Postage is free.

    Cotz is another brand i am looking out for. Not expensive. Lots of budget options in my list i shared.
  • Maybe Wix is telling me i have used up my "free" bandwidth, i have been having issues with speed with the "free account" i have. 

    doh!

    need to pay them.... 


    Don't get Curel yet... i have one on the way... i'll test it and do a patch test to share so you can see for sure if the color /white cast is ok. the UVA coverage isn't the max.. only PA+++ (max is PA++++)

    Badger is not a makeup friendly sunscreen but a very good sunscreen.

    anyway .. what s 2mg/cm2? they calculate 1tsp (5ml) for the neck and face... for the death of me i can't even use up 1/2 tsp let alone 1 tsp! maybe i am using 1/4tsp at best.
    my face is smaller than the 1 tsp they calculate (average man's face) so how would we calculate the quantity used? face size in cm2? hehe. this is too technical for me.

    escherichia yes i totally agree with wasting money on products you don't want.. and can't bear to toss. Fortunately i did a swap with someone in Sydney for the Moogoo sunscreen (she didn't like it) and there were no testers in the store, no reviews either. I swapped it with something i don't use. As it came in an airless bottle, i was ok with it. normally i am a germaphobic. Cost only AUD$3 to mail a sample sachet. Would be happy to share... anyways. Babo is only USD17 a tube. Postage is free.

    Cotz is another brand i am looking out for. Not expensive. Lots of budget options in my list i shared.
  • edited October 2016

    is Peter is right about The chemical filters, this is the one i really want to try

    Kanebo ALLIE Extra UV Gel SPF50+ PA++++

    image

    Active Ingredients: Zinc Oxide, Octinoxate, Uvinul A Plus & Tinosorb S

    Skinfit technology making it more resistant to water, sweat and sebum therefore last longer

    Includes blend of skin beautifying treatment

    Full ingredients here: http://www.ratzillacosme.com/sun/kanebo-allie-extra-uv-gel-mineral-moist-neo/

  • Preciousia,

    Thank you so much! My friend is going to Japan in October 21 so I've asked her to get me a bottle of that Curel UV if she sees it in the drugstores. If you happen to test Curel UV before then then, pls kindly let me know. :)

    Perhaps I should swap my sunscreens away too. I have 3-5 brand new sunscreens (seal not even broken) and 1-2 suncreens that I've tried but don't like. But I just hate the fuss of shipping... buying bubble wrap, wrap, buy envelope, go PO... u can see what a lazy person I am LOL.

    And you know what? I totally agree with you on the 2mg/cm2. I was quite fanatic about it and upon someone's suggestion on reddit, I tried to use saran wrap to measure my face. It's not gonna be totally accurate but the wrap is soft so it's easier to measure, and you can always accommodate for extra. I cut out the saran wrap rectangle (more surface area is better than less, right?) and my face (I don't really care for my neck...) is about 600cm2. I didn't weigh my sunscreens (density matters) but going by the 2cm/cm2, I really do need about 1/6 to 1/4 teaspoon.

    And that's A LOT. Yes, I suppose I can do it in 2 or 3 layers but for pure physical sunscreens, no matter what I do, I'm gonna look like a freaking ghost (I envy you people who can take chemical sunscreens).

    So I gave up. I rather apply a thin layer and get SPF5 then go out with no SPF. 

    I tell myself, at worse, I will look like a spotted hag when Im 60 (well, I might not give a s**t about how I look then). Hopefuly, no skin cancers...

    I'm gonna go take a look at the Babo botanicals sunscreen now.
  • edited October 2016
    escherichia By the way, your comment has prompted me to shell a few bucks and pay Wix for their hosting. 2GB of bandwidth. it is a little faster now. i hope. i am fond of how user friendly they are. i don't have to worry about backing up as well. there are limitations of course.

    If your friend is going to Japan, it will be good. i know lots of Japanese products to recommend if it is along the way for them. 

    Actually, postage from Australia to overseas is insane for any bottles. I am suggesting only sachets like a 5ml sample perhaps. (that way i pay the costs of postage for a Christmas card)  A sachet will allow for patch testing and color etc... I don't mind mailing things out... it's the costs of postage that is not worth while. would be better buying from the sources i mentioned. probably cost the same. lol
    from here to Canada cost AUD$16 for a 500g bag. 

    This is how much Babo Botanicals i applied on my face.lol trying to aim for 1/2 tsp
    image

    image
    looks familiar? 
    Get a SPF50... apply half and get SPF25 which is 96% protection :) or even at a quarter it is 92%

    or a SPF40 halved is SPF20 which is 95% or quarter SPF10 is 90%

    either way. get protected! and reapply!

  • Preciousia,

    I can FINALLy see the photos! So it was the bandwidth that was messing your website up! And wow, that's  ALOT of sunscreen. U are tempting me to get this... should I wait for my Innisfree to come first? Hahha
  • And oh, please do recommend good Japanese products for me hehe. I can read Japanese but I'm really seriously out of touch with skincare... 
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