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  • Sunscreen selection

    NEW format! Long, technical bits have been added in Times Roman font so that you can easily scroll through them to the next section if you wish

    I'm not trying to discourage questions, but sunscreens seem to be an issue where similar questions pop up all the time. I hope that by sticking up a FAQ-like sort of thing, it will make looking for answers much easier for everyone.

    There will always be a Sunscreen Talk thread where we discuss issues not described here. Currently it's at: http://forums.cozycot.com/showthread...&threadid=5969
    Useful info will be copied here.

    No, I'm not a skincare or sunscreen expert, whatever that is. I suck at science! But I have read up quite a bit on the subject, and think I have an objective and scientific POV on the topic. If there's anything you don't agree with, tell me why you think so.

    No, I'm afraid I don't remember the details of every sunscreen I've come across. But I hope this forum will provide everyone with enough knowledge to find the sunscreen that's perfect for them!


    UV damage is the sort of thing which isn't really evident until later in life; I'd rather invest in good sunscreens now than expensive "anti-aging" creams and serums later.

    To start off, this is what I look out for in a sunscreen:

    - minimum of SPF30 (really important no matter what the FDA says)
    - maximum UVA protection, so PA+++ (only shown on products exclusive to the Asian market) or PPD15 and above (products for European or Canadian markets)
    - zinc oxide or Mexoryl SX & XL or Tinosorb S & M, as these provide the best broad-spectrum protection. Zinc oxide should be among the first few ingredients listed.

    At the time of writing, my favourite sunscreens are
    - Sunkiller Clearwater SPF50 (zinc oxide and octyl methoxycinnamate)
    - L'Oreal UV Perfect 50 (Mexoryl SX/XL and titanium dioxide)

    SUNKILLER
    I like Clearwater 50 because it's the lightest. If you like shimmer, Beauty Skin Water 50 is good. Powder-in Milk 50 has menthol and is best kept for the body only. If you're going to be spending long hours in the sun, you're better off with Clear Milk 85 or the tinted Lift-tight skin tone Milk 135. The others in the range have only PA+ or ++ and do not give sufficient protection.

    French sunscreens
    I'm a big fan of French sunscreens, especially those from brands under the L'Oreal group, containing their patented Mexoryl XL. The Anthelios series under their La Roche-Posay has excellent sunscreens. Lancome and drugstore L'Oreal have the lightest of the lot. Avene and RoC make good sunscreens too.

    US and Australian
    IMO, their most notable sunscreen products contain micronised zinc oxide and/or titanium dioxide. They are lighter in texture and aren't as opaque, and so are cosmetically more pleasing. But because of the same reason, the protection cannot be described as optimum. Good enough for most everyday use.

    That's a pretty good summary of this thread! Read on for more.

    One last thing: there is good reason why Japanese women like hats. And if you worry about crows feet, don't forget your sunglasses.
    Last edited by saresha; 21-03-2005, 03:42 PM.

  • #2
    Some Japanese sunscreens

    Sunkiller comes in different formulations, but Clearwater SPF50 has zinc oxide and octyl methoxycinnamate. IIRC, the higher SPFs have also got titanium dioxide.

    Anessa SPF50 has zinc oxide, avobenzone (Parsol 1789), octyl methoxycinnamate, and octyl triazone. For some reason, zinc oxide is near the bottom of the list, which isn't very reassuring, especially for such an expensive product.

    I don't like Sunplay sunscreens because they don't contain zinc oxide. I need sunscreens to provide optimum, photostable (does not break down in UV light - which sort of defeats the purpose) UVA/UVB protection.

    OMi isn't quite as light as Anessa 50 or Sunkiller clear water, but it's lighter than Pola Suncut Milk. If you hold Anessa 50 as your standard for lightness, the Pola isn't going to cut it (pun unintended).

    Some of you have noticed that OMi doesn't have a very impressive list of ingredients. When it was previously available here (back in '01) there was most definitely zinc oxide and titanium dioxide. Either the formulation has changed, or the local importer has made a mistake with the ingredients labelling in English.
    Last edited by saresha; 30-12-2003, 12:55 AM.

    Comment


    • #3
      Reading the ingredients list

      Originally posted by latte
      Saresha, does it matter if zinc oxide and the rest of the essential ingredients are the last few in sequence on the ingredient list? Or they must be of a minimal %, eg 5% of zinc oxide, in order to qualify as one good sunblock?
      Ideally there should be % shown, but otherwise they should be separately listed as "active ingredients", or at least within the first half of the list. Ingredients are normally listed in order of quantity.

      Zinc oxide and titanium dioxide often occur in products in small quantities, not to provide sun protection, but to give coverage. It's their opaque nature that allows UV light to "bounce". That's the reason some foundations photograph badly (ie. make you look ghostly) - it's the flash light reflecting from your skin.

      Variable Chemical Names in Sunscreens, and Abbreviations

      Terephtalilydene Dicamphor Sulfonic Acid = Mexoryl SX [= Ecamsule]
      Drometrizole Trisiloxane = Mexoryl XL
      Bis-Ethylhexyloxyphenol Methoxyphenyltriazine = Tinosorb S
      Methylene Bis Benzotriazolyl Tetramethylbutylphenol = Tinosorb M
      Butyl methoxydibenzoylmethane = Parsol 1789 = Avobenzone = BMDM
      Diethylamino Hydroxybenzoyl Hexyl Benzoate = Uvinul A+
      Benzophenone-3 = Oxybenzone = OXY
      Octyl methoxycinnamate = Ethylhexyl methoxycinnamate = octinoxate = OMC
      Octyl salicylate = Ethylhexyl salicylate = octisalate
      Ensulizole = Phenylbenzimidazole Sulfonic Acid
      4-Methylbenzilidene Camphor = 4-MBC
      Octocrylene = OCTO
      Zinc Oxide = ZO
      Titanium Dioxide = TiO2

      From MUAer nora80's notepad
      http://www.makeupalley.com/user/notepad/nora80/

      BASF patented UV Absorbers

      UV Absorber (UVA)
      Uvinul BMBM = Butyl Methoxydibenzoyl Methane

      UV Absorber (UVB)
      Uvinul MC80N = Octyl/Ethylhexyl Methoxycinnamate
      Uvinul MC80 = Octyl/Ethylhexyl Methoxycinnamate (UVB filter available in two forms: stabilized with BHT and non-stabilized)
      Uvinul T150 = Octyl/Ethylhexyl Triazone (UVB filter with the highest UV absorption, no skin penetration and excellent photostability)
      Uvinul M40 = Benzophenone-3
      Uvinul MS 40 = Benzophenone-4
      Uvinul DS 49 = Benzophenone-9
      Uvinul D 50 = Benzophenone-2
      Uvinul 400 = Benzophenone-1
      Uvinul N 539 T = Octocrylene (an efficacy booster whose protection extends to the short-wave UVA spectrum, enhances the effect of other UV filters and stabilizes avobenzone)
      Uvinul MBC 95 = Methylbenzylidene Camphor
      Uvinul P 25 = PEG-25 PABA
      Uvinul A Plus = Diethylamino hydroxybenzoyl hexyl benzoate (provides efficient protection in the long-wave UVA-I range with an absorption spectrum of up to 400 nm; stable against photo decomposition; highly compatible with other organic UV absorbers and microfine pigments such as ZnO and TiO)

      UV Chelate
      Z-Cote = Zinc Oxide
      Z-Cote HP 1 = Zinc Oxide and Dimethicone
      Uvinul TiO2 = Trimethoxycaprylylsilane and Titanium Dioxide
      Last edited by saresha; 21-03-2005, 01:51 PM.

      Comment


      • #4
        Side effects?

        Originally posted by Glossie So, with all these minerals that affect the thickness and efectiveness of the sunblocks, should I be concerned that these same good stuff is also prone to clogging pores??? A facial lady told me once that that's the other side of the coin. Please set the record straight!
        Minerals can indeed clog pores. Paradoxically, they are also more suitable for sensitive skins, being inert. Sometimes it's not the filter agent, though, that causes problems, but the other stuff in the product ('vehicle'). One possible solution is the use of micronised minerals (see next page).

        Ultimately I guess you have to decide for yourself what's more important when it comes to your skin.
        Last edited by saresha; 21-03-2005, 03:45 PM.

        Comment


        • #5
          A few reminders!

          In answer to some of the other issues raised:
          - Yes, by all means use Sunkiller on your body. But for sports, I'd use something more heavy duty, like a high SPF Avene, Anthelios, ROC, etc.
          - Yes to sunblock around the eyes. Some people experience a stinging sensation, though. There are special eye sunblocks, but only a few offer adequate protection. Check the ingredients first! I have no problems whatsoever with using my usual face sunblock around the eyes. Dab carefully and don't let it get into the eyes.
          - It's tempting to rub sunscreen between your hands and then over your face, I know. I do that with moisturiser. But if I were you, I'd apply my sunscreen more carefully. Most of us don't apply nearly enough product, you don't want some of it to end up protecting your palms instead!
          - DON'T mix your sunscreen with other products, like moisturiser or foundation. You may end up halving the protection or worse.
          Last edited by saresha; 29-12-2003, 11:31 PM.

          Comment


          • #6
            Physical vs. chemical

            Physical filters are minerals, most commonly zinc oxide and titanium dioxide. They are opaque and reflect UV rays. They give broad-spectrum protection (both UVA and UVB), though comparison between zinc oxide and titanium dioxide shows that zinc oxide is superior for UVA protection in the 340-380 nm range (UVA-I) and tends to be less pasty on the skin. In their normal, non-micronised state, they are inert and photostable (ie. they do not break down in UV light).

            Chemical filters are, well, chemicals, and include just about every other UV filter. Being chemicals, they are light and invisible. They absorb UV rays. Unfortunately, some are not photostable and most of them do not give broad-spectrum protection. Parsol 1789 (Avobenzone), which you see a lot in US products, protects against UVA but is not photostable.

            New chemical filters like Tinosorb and Mexoryl are not only photostable and broad-spectrum, but they have a stabilising effect on other agents as well.

            Read more about chemical filters in the relevant post further down.

            If your sunscreen contains chemical filters, be sure to apply 15-30 minutes before exposure to the sun. If it contains only physical filters, applying it just before exposure is fine.
            Last edited by saresha; 21-03-2005, 03:49 PM.

            Comment


            • #7
              SPF15 vs SPF30

              There seems to be some confusion concerning the necessity of using >SPF30, since many doctors and the FDA maintain that SPF15 is sufficient.

              Arguably, a SPF 15 sunscreen provides full UV-B protection for healthy individuals. A SPF 15 product filters out more than 93% of UV-B radiation, and a SPF 30 product filters out less than 97%. The difference of 4% would not seem significant to most individuals. Product application technique outside the laboratory alters the SPF. As previously noted, the standard FDA method for SPF testing involves a sunscreen application thickness of 2 mg/cm2. Several studies indicate that under in vivo, real-world conditions, application thickness more likely approximates 0.5-1.0 mg/cm2, lowering the effective SPF of the product. When SPF testing is conducted outdoors, the efficacy of products is found to be lower than in the laboratory.

              Erythema, the key measurement in the SPF assay, is a relatively crude biologic endpoint. A comparison of a SPF 15 sunscreen versus a SPF 30 sunscreen showed subclinical damage (sunburn cell formation) in the former without visible erythema. The SPF 30 product provided significantly greater protection. Other forms of subclinical damage may occur with a SPF 15 formulation. Although UV-A protection may be less than desirable with all sunscreen products, the UV-A protection is better with a higher SPF, particularly in the UV-A II (320-340 nm) or shorter UV-A range.

              from Sunscreens and Photoprotection by Stanley B Levy, MD
              http://www.emedicine.com/derm/topic510.htm


              If you are interested in reading a more detailed discussion of this issue, go to this article from The Electronic Textbook of Dermatology http://telemedicine.org/sundam/sundam2.4.2.html and scroll to the section on High SPF Sunscreens and FDA.


              Basically, a minimum SPF30 is ideal. I don't think you should worry about anything higher (though I don't think they'll do you any harm either).

              Unprotected time in the sun w/o minimal sunburn x SPF = Protected time in the sun w/o minimal sunburn

              This is only under lab conditions, where test subjects apply the recommended amount of product. The truth is in real life, people apply much less. Thus anything less than SPF30 will not protect you sufficiently. Note that this only refers to protection from UVB rays, and not UVA. Also, SPF is no indication of photostability. Most chemical UV filters break down in the sun, which shortens the amount of time you are protected.
              Last edited by saresha; 21-03-2005, 03:47 PM.

              Comment


              • #8
                UVA ratings

                Products made for the Asian market typically include the Japanese PA rating (PA+, PA++, PA+++). On European products you see IPD and PPD ratings and these refer to UVA protection. Apparently PA+++ corresponds to a PPD rating of at least 8, with PPD 15 being the ideal minimum. However, the IPD, PPD and PA rating systems are based on in vivo test methods, and are not regarded to be as reliable as in vitro rating systems such as the Australian Standard or the Boots Star Rating System (latter as seen on Boots sunscreens: *, **, ***, ****).

                See below for more on these.

                Japanese PA Rating

                With respect to an index or measurement methods for UVA protection, however, a uniform measurement method has not yet been established on a national or industry-wide level although several papers on the subject have been published, and studies are underway in various countries. Throughout the world there are products displaying numerical values, etc., for UVA protection, but because there is particular concern that a uniform measurement method has not been established in Japan and these numerical values may cause confusion among consumers in their product selection, it has been decided not to employ some types of index to list the level of UVA protection on cosmetic products.

                Therefore, for the purpose of establishing a method for measuring UVA protection, the Technical Committee of the Japan Cosmetic Industry Association reorganized its previous SPF task force in November 1992 and established the Ultra Violet task force. This task force has handled the basic research project on UV protection approved and sponsored by the Japan Human Science Foundation and has compiled its results in this document.

                The fundamental principles toward the standard are described below:
                (1) The standard is intended to provide uniform measurement method of PFA (Protection Factor of UVA) values and labeling method for the grade of UVA protection on sunscreen and suntan cosmetics enable consumers to select products which meet consumers desired W light protection efficacy.
                (2) The standard shall go into effect on January 1, 1996.
                (3) The standard shall be reviewed when new technological findings warrant it.

                ...

                - MPPD (Minimal Persistent Pigment Darkening Dose)
                The MPPD is defined as the minimum dose of UV rays that produces slight darkening over essentially the whole radiation field within 2 to 4 hours after exposure.

                - Calculation Method of the PFA Value
                PFA value shall be obtained from the following equation by using MPPDs at sites untreated and treated by a test sample.

                PFA value = MPPD in protected skin/MPPD in unprotected skin

                PFA value of a test sample is defined as the arithmetic mean of each subject?s PFA values obtained from the above equation.

                - Method for Expressing UVA Protection
                For labeling PFA values in UV protecting products, the figures to the right of the decimal point shall be discarded from the PFA value of the sample that has been calculated according to the above method to make it an integer. Then, when the value is not less than 2, it shall be classified according to the following PA (Protection grade of UVA), and this classification shall be expressed on the label. PA shall be placed together with the SPF value.

                PFA Value : PA (Protection grade of UVA)
                2 or more but less than 4 : PA+
                4 or more but less than 8 : PA++
                8 or more : PA+++

                From FDA docket Japan Cosmetic Industry Association
                Measurement Standards for UVA Protection Efficacy

                http://www.fda.gov/ohrms/dockets/dai...ppendix_03.pdf

                ?In-vitro? methods

                Australian Standard (AS/NZS 2604:1997)

                In Australia, the official method is an in-vitro method that measures the power of absorption of the product by
                spectrophotometry. The expression of the results are carried out as a percentage of UVA radiation absorbed by the sun product. Different supports may be used for these types of measurements (quartz plate, thin film, solution). According to the Australian standard, a product with a long wave spectrum should not allow more that 10% of the radiation between
                320 and 360 nm at to pass through.

                Diffey and Robson Method

                In England, the in-vitro method is based on the Diffey and Robson method and the star system developed by Boots in 1991. Diffey and Robson fine tuned the in-vitro method that measures the transfer of ultraviolet radiation through a film, Transpore
                Tape. 2 mg/cm of the sun product to be analysed are applied on this support medium representing the skin. The ultraviolet radiation transfer measurements are then taken every 5 nanometers from 290 through 400 nm.

                The UVA/UVB radiation coefficient introduced by Boots consists of establishing a factor for the area of the absorption curve for the UVA radiation (320-340 nm) obtained, with respect to the area of the absorption curve for the UVB radiation (290-320 nm). The result is a coefficient defined between 0 (with no protection from UVA radiation) and 1 (protection from UVA radiation equal to the protection from UVB radiation). The results are translated depending on the coefficient using a star rating system between 1 and 4.

                From ROCHE Skin and Sun
                http://www.roche.com/vitamins/pdf/skin_and_sun.pdf

                SPF and UVA

                The definition of UVA-protection is far from harmonisation. It is not only the testing, but also the labelling, that is not standardized.

                There are still unanswered questions concerning UVA-protection, e.g.:

                * What level of UVA-protection is adequate?
                * Which is the most relevant and measurable skin response to indicate UVA-induced skin damages?
                * Which absorption profile should an ideal sun care product have?
                * Which UVB/UVA-ratio should be considered to meet different irradiation situations?

                In 1994 the German health authorities invited experts to discuss UVA-protection issues. It has been concluded that all sun-protection products should have adequate UVA-protection, but a clear definition of what adequate means, is not given by the lack of scientific background.

                Test methods used until now are the in-vitro

                * Australian Standard AS,
                * the Boots Star Rating system,
                * the Broad Spectrum Rating
                * and the APP?Method / UVA-Protection Percentage

                These methods are all based on transmission/absorption measurements. They differ in details and the methods of calculation. The results are usually used as indicator for UVA-protection or broadness of the absorption characteristic.

                In-vivo methods are:

                * IDP method (Immediate Pigment Darkening)
                * PPD method (Persistent Pigment Darkening)
                * APF method (Erythemal UVA- Protection Factor)
                * PPF method (Phototoxic Protection Factor)

                The in-vivo methods are based on the determination of UVA-induced skin responses (e.g. pigmentation or erythema) followed by a calculation of UVA-protection factors analogue to the SPF. The results obtained diverge significantly between methods, but may also lead to different efficacy rankings.

                As the in-vivo method cannot measure directly the target skin responses (ageing, immunosuppression, cancer) the results can only be seen as indicative.

                Therefore, the value and necessity of in-vivo UVA-testing has been questioned by several scientists, especially the additional benefit of the in-vitro measurements.

                For the customer, having just become familiar with the SPF system, the existing UVA-labelling (contains UVA-protection, Broad-Spectrum protection PA+-PA+++ and B20A6 or SPF60-IPD 55-PPD 12) is more confusing than informative.

                A simple and easy?to-understand system is to be demanded, like the in?vitro determination of Broad-Spectrum criterion. An in-vivo Broad-Spectrum is reached by Octyl Methoxycinnamate and Zinc Oxide, and an even greater Full-Spectrum protection is reached in-vivo with the use of Octocrylene and Parsol1789.

                From Sun Protection: Dermatological and Cosmetical Aspects
                Werner Voss, M.D., Dermatest
                http://www.dermatest.de/PB/Publikati...rotection.html

                Assessment of UVA Protection

                Increasing awareness of the need for skin protection against the UVA portion of the solar spectrum (320-400 nm) has accelerated development of sunscreen products that provide substantial UVA protection. Since these products have labeled SPF values similar to those of products that provide primarily UVB protection (290-320 nm) and relatively little UVA protection, there is a need for a reliable and informative index of UVA protection.

                Assessment of UVA protection is a formidable problem, because sunlight is always a mixture of UVA and UVB, and the immediate and long-term effects of UVA are normally masked by the effects of energy in the more potent UVB wavelengths. Separation of UVA effects from those of full-spectrum UV is difficult, and eliciting measurable responses to UVA alone requires high energy doses and relatively long exposure times.

                Proposed human in vivo methods for assessing UVA protection include the immediate pigment darkening, persistent pigment darkening and PFA methods. While each has its own advantages, none is completely adequate for assigning a clinically relevant index of sunscreen protection in the UVA region. For this reason, an in vitro method appears to offer the best alternative for assessing UVA protection. Following is a discussion of the available in vivo methods and the advantages of in vitro methods.

                Immediate Pigment Darkening

                The immediate pigment darkening (IPD) response is a transient brownish-gray coloration of the skin of individuals with pigmented skin after irradiation with UVA radiation. The response is evaluated within 60 seconds after UVA exposure. The IPD protection factor is the ratio of the UVA dose required to produce the response, with and without a sunscreen on the skin.

                The IPD test produces rapid results with low doses of UVA. However the response is highly variable and difficult to reproduce accurately. Its clinical significance is low because the action spectrum for IPD differs widely from action spectra for erythema and tanning, non-melanoma skin cancer and photoaging.Further, the test is performed using human subjects with skin types III and IV, who are not the individuals who have the greatest need for sun protection. The low UVA doses involved may conceal the effects of sunlight on the stability of the product.

                Persistent Pigment Darkening

                The persistent pigment darkening (PPD) response is a longer lasting response of individuals with pigmented skin after irradiation with UVA radiation. The response is evaluated 2 to 24 hours after UVA exposure. The PPD protection factor is the ratio of the UVA dose required to produce the response, with and without a sunscreen on the skin.

                The PPD test produces rapid results with moderately low doses of UVA. The response is stable and reproducible, however Its clinical significance is also low, as in the case of IPD, because the action spectrum for PPD is not defined for wavelengths shorter than 320 nm. Further, the test is performed using human subjects with skin types II, III and IV, which do not include Type I individuals who have the greatest need for sun protection.

                PFA

                The PFA (protection factor A) method is based on the minimal response dose (MRD), which is the smallest UVA dose that produces a minimal erythema or tanning response. A substantially higher energy dose is required to produce the erythema or tanning response to UVA than that required to produce an erythema or tanning response to UVB, with consequently longer exposure times. The response is evaluated 22 to 24 hours after exposure, and is stable, reproducible and clinically significant, in that the action spectra for erythema and tanning are similar to those for skin cancer and photoaging. Further, the test is performed using human subjects with skin types I, II and III, who are the individuals who have the greatest need for sun protection. The UVA protection factor, PFA, is the ratio of the MRD for sunscreen-protected skin to that for unprotected skin.

                Advantages of in vitro Methods

                A major disadvantage of all in vivo methods is that available UVA sources do not fully reproduce the UVA portion of the solar spectrum.


                Sunscreen UVA protection may be evaluated by measuring the product UV transmission spectrum determined in vitro. Once a representative transmission spectrum has been measured for a given product, the degree of UV protection against any effect for which an action spectrum is known may be assessed for any known natural or artificial UV source. The product UV transmission spectrum may be validated by computing the SPF and comparing the SPF determined in vitro to that measured in human subjects. Then the UVA protection factor (PFA) may be computed for a representative solar spectrum.

                http://www.suncarelab.com/UVA.htm


                Carol Demas and Barbara Kwiatkowska in The Biochemistry of Beauty

                European sunscreens with high PPD ratings and multiple chemical UVA filters are far more protective than the best currently formulated Asian and USA sunscreens.

                They can provide:
                * at least 3 times as much protection as the most protective USA formulations
                * at least 3 times as much protection in UVA as a product that employs only physical UVA filters
                * probably 3 times the protection of the most protective Asian formulations

                The preponderance of evidence from over 140 primary medical studies suggests that using the highest UVA protection is more important for cancer prevention and minimization of photodamage than avoidance of chemical UVA filters.

                Details are here:
                Research highlights from La Roche-Posay

                European and Canadian formulas:

                Look for two or more of the following:

                Chemical filters that cover an appreciable part of UVA include
                * avobenzone (INCI name: butyl methoxydibenzoylmethane)
                * mexoryl sx (terephthalylidene dicamphor sulfonic acid)
                * mexoryl xl (drometrizole trisiloxane)
                * tinosorb s (bis- ethylhexyloxyphenol methoxyphenol triazine)
                * tinosorb m (methylene bis-benzotriazolyl tetramethylbutylphenol)

                Physical filters
                * zinc oxide
                * titanium dioxide

                If the sunscreen does not have a PPD rating of at least 15, then look for three or more of the above chemical and physical filters and look for the highest possible concentration of each.

                Examples:
                La Roche Posay Anthelios SPF 60/PPD 28-30 XL Lait and Cr?me
                Bioderma Photoderm Max SPF 100 PPD 30
                SVR 100B SPF 100 PPD 30
                L?Oreal Solar Expertise IP 60, estimated PPD > 15
                Vichy Capital Soleil Spray SPF 40/PPD 18

                Asian formulas:

                Look for a formulation that has the rating PA+++. This corresponds to a PPD protective factor of at least 8. If you seek a higher PPD rating, you should consider European formulations.

                Example:
                Sunkiller SPF 85 PA+++

                USA formulas:

                Look for a formulation that has either
                1) avobenzone 3% + octocrylene (>=8%) or some other avobenzone stabilizer
                or
                2) a purely physical sunscreen with a high concentration of zinc oxide and/or titanium dioxide, which is very likely to leave a white or bluish cast on the skin

                Examples:
                Ombrelle SPF 40 lotion
                Ombrelle SPF 44 lotion for kids
                Ombrelle SPF 28 spray for kids

                All formulas:

                If the formulation includes avobenzone, look for a stabilizer in the ingredients list. Stabilizers for avobenzone include:
                * octocrylene
                * 4-methylbenzylidene camphor
                * tinosorb s
                * tinosorb m
                * butyloctyl salicylate
                * hexadecyl benzoate
                * butyloctyl benzoate
                * mexoryl sx
                * diethyhexyl 2,6-naphthalate (DEHN) http://www.fda.gov/ohrms/dockets/dai...99/c000586.pdf

                There is no FDA requirement for stability.

                Metal ions and formaldehyde donor preservatives must also be avoided for stability of avobenzone.

                Comedogenicity:

                Many cream formulations are highly emollient and likely to be comedogenic when used by an acne-prone person. Lotions (laits) are somewhat less so. European and USA gels or sprays tend to be the lightest and least comedogenic, along with many Asian lotion formulations. If you are breakout-prone, look for a gel, a spray, or an Asian sunscreen.
                Last edited by saresha; 21-03-2005, 01:21 PM.

                Comment


                • #9
                  Doing your homework!

                  Even experts don't always agree, and it's well known that many American dermatologists don't agree with the FDA guidelines. There are in fact many websites out there that provide the results of scientific studies on sun protection. Here are some of my favourites:
                  http://telemedicine.org/sundam/sundam2.4.1.html
                  http://author.emedicine.com/ped/topic2561.htm
                  http://www.photodermatology.com/sunprotection.htm
                  http://tinyurl.com/wr0g
                  http://www.dermatology.org/skintherapy/stl0205.html
                  http://www.emedicine.com/derm/topic510.htm
                  http://www.emedicine.com/ped/topic2561.htm

                  There is some repetition, but they are not all equally technical, so skip when it gets too much. I base my advice on sunscreen selection on these sites. For instance, a minimum of SPF30 for every day (rather than the SPF15 rec'd by the FDA).

                  I agree with Glossie, reading up on your own and forming your own opinions is the best way to go. Not everyone is so particular about sun protection, and that is certainly a personal choice. For many people, ease of wear is the biggest factor. Plus we spend different amounts of time in the sun. Just don't forget that even the best sunscreens don't give us 100% protection.
                  Last edited by saresha; 20-03-2005, 12:47 AM.

                  Comment


                  • #10
                    20+20=40? Er, no, actually.

                    Originally posted by elainetsai
                    If i have a foundation with 20 spf and a suncreen with 20 spf, do i get a protection of 40 spf if i use both together, or is it still 20?
                    Still SPF 20. Remember that sunscreen is meant to be applied generously to obtain the stated SPF, and that we don't usually apply that much foundation (or moisturiser, for that matter).

                    It's just as well that we don't usually slap on that much moisturiser or foundation. If you use two products, one with a higher SPF and one with a lower, you run the risk of diluting the higher SPF. If you use two products, one with SPF and one with none, you also end up diluting the SPF. It's good practice to allow layers to absorb nicely before applying the next.
                    Last edited by saresha; 29-12-2003, 11:35 PM.

                    Comment


                    • #11
                      How much is enough?

                      Are you applying enough?

                      The Food and Drug Administration recommends that 1,000 microliter be applied per 50 square centimeters of skin. What does this actually mean in practical terms? The average adult face has an area equal to a piece of typing paper (try draping a piece of typing paper over your face and you?ll see that I?m right.) That translates into about 810 to 820 square centimeters. That in turn would translate into 1.6 cc of sunscreen for the face. A teaspoon equals 5cc. If you were to be on the safe side and apply 2cc you would be applying about 4/10 of a teaspoon of sunscreen to cover an area the size of your face.
                      From http://www.iranderma.com/text1.htm


                      So that's 2/5 of a teaspoon.

                      A sun product with a protection factor of 25, will effectively give a sunscreen protection factor (SPF) of 25, if the product is correctly applied under the same conditions as the experiment, that is, at a level of 2 mg/cm. However if the amount applied is no more than 1 mg/cm, approximately half of the quantity used for in experimental determinations, then the actual sun protection factor will not be reduced to around half but will be signicantly lower, probably only 20- 25% of the stated SPF figure. Furthermore, skin is not a flat surface, but is made up of cavities and crests and if an insufficient amount of cream is applied, it has a tendancy to be localised in the cavities leaving the crests unprotected. If only a small
                      quantity is applied then this uneven coverage will be exaggerated.
                      From ROCHE Skin and Sun
                      http://www.roche.com/vitamins/pdf/skin_and_sun.pdf


                      That said, 2/5 tsp is the recommended amount set by the FDA in the US, where most sunscreens are quite thick, so I feel you have to adjust according to the formula and possibly use less. I tried recently to actually measure out 2/5 tsp of a Japanese sunscreen (the very liquid type), and there's no way I could put all of it on my face! I ended up drying out my skin (too much alcohol). Henceforth I will just try my best to get even coverage and not miss any spots (a bit tricky when the formula is so sheer and light).
                      Last edited by saresha; 28-03-2005, 06:33 AM.

                      Comment


                      • #12
                        UV through glass?

                        Most glass used for windows blocks UVB but not UVA. This means that although glass greatly reduces the risk of sunburn, it does not prevent long term damage from UVA. So, if you are driving long distances or sitting in your conservatory every day for long periods of time, with the sun beaming in on you, then you are putting yourself at risk. This does not necessarily mean that you would get skin cancer but you would be at risk of damaging your skin in some way.
                        From http://www.cancerhelp.org.uk/help/default.asp?page=5413

                        85% of UVA radiation passes through glass as opposed to 3.5% for UVB radiation

                        UVA radiation, available in significant amounts, and having an intensity not dependent on the time of day, but without producing any physical warning of overexposure (such as sunburn in the case of UVB radiation), is filtered to a negligible extent by materials such as glass. Thus, window glass may stop 96.5% of the UVB rays but only 15% of the UVA radiation. A similar process occurs with car windscreens and side windows where 90.2% of the UVB radiation is stopped as opposed to 30% of the UVA rays. Additionally, UVA radiation has a greater capacity to penetrate water than UVB radiation.

                        From http://www.roche.com/vitamins/pdf/skin_and_sun.pdf
                        Last edited by saresha; 21-03-2005, 10:11 AM.

                        Comment


                        • #13
                          Chemical filters

                          Chemical filters are largely not photostable, but there are some exceptions. (But photostable or not, chemical filters by themselves never provide sufficient broad-spectrum protection; they must be combined with physical filters.)

                          Mexoryl SX and Mexoryl XL, under L'oreal patent, are photostable chemical filters. Mexoryl and titanium dioxide are normally used together.
                          Read about Mexoryl here: http://www.loreal.com/_en/_ww/loreal.../capital.aspx?
                          L'oreal, Lancome, La Roche Posay, Biotherm and Vichy are some locally available brands that offer Mexoryl sunscreens. The more lightweight ones include Lancome UV Expert, L'oreal UV Perfect, and LRP Anthelios Fluide Extreme. Find LRP sunscreens here:
                          http://www.mypharmacy.com.sg/ShopFro...aspx?CatID=288 and at selected Guardians.

                          Tinosorb M and S, under Ciba patent, are also photostable.
                          Read about Tinosorb here: http://www.cibasc.com/index/ind-inde.../ind-pc-uv.htm
                          Tinosorb can be found in Avene, ROC and some other European sunscreens.
                          Here's an independent study on Tinosorb S: http://tinyurl.com/5z9qy
                          The latest Avene sunscreens in the orange packaging contain MPI-SORB, a combination of mineral filters (titanium dioxide and zinc oxide) and Tinosorb M. (White packaging sunscreens are non-chemical, ie. only zinc oxide and titanium dioxide.) Avene is available at selected Guardians and http://www.mypharmacy.com.sg/ShopFro...aspx?CatID=288

                          BASF, the same people who patented Z-Cote, has patented some other photostable chemical filters:
                          Uvinul MC80 = Octyl/Ethylhexyl Methoxycinnamate (UVB filter available in two forms: stabilized with BHT and non-stabilized)
                          Uvinul T150 = Octyl/Ethylhexyl Triazone (UVB filter with the highest UV absorption, no skin penetration and excellent photostability)
                          Uvinul N 539 T = Octocrylene (an efficacy booster whose protection extends to the short-wave UVA spectrum, enhances the effect of other UV filters and stabilizes avobenzone)
                          Uvinul A Plus = Diethylamino hydroxybenzoyl hexyl benzoate (provides efficient protection in the long-wave UVA-I range with an absorption spectrum of up to 400 nm; stable against photo decomposition; highly compatible with other organic UV absorbers and microfine pigments such as ZnO and TiO)
                          Originally posted by marie
                          it seems that octocrylene has been shown to photostabilize avobenzone. is this true?
                          Yes. Other avobenzone stabilisers are 4-methylbenzylidene camphor, Tinosorb S, Tinosorb M, butyloctyl salicylate, hexadecyl benzoate, butyloctyl benzoate, Mexoryl SX and diethyhexyl 2,6-naphthalate. (Eg. LRP Anthelios 60 XL Fluide Extreme has Mexoryl SX and XL, octocrylene, avobenzone, as well as titanium dioxide.)

                          However, avobenzone also has the potential to degrade other sunscreen ingredients in products in which it is used. In particular, avobenzone, even when stabilised by octocrylene or methylbenzylidene camphor, is destabilised by the presence of ethylhexyl/octyl methoxycinnamate.
                          See http://tinyurl.com/5z9qy

                          European sunscreens with Mexoryl or Tinosorb
                          by Barbara Kwiatkowska

                          Manufacturers:

                          TINOSORB
                          - Avene
                          - Bioderma
                          - Castalia
                          - Caudalie
                          - Cosmedex
                          - Daylong
                          - Ducray
                          - Evaux
                          - Galenic
                          - Johnson's Suncare Baby
                          - Laboratories SVR
                          - Laviderm
                          - Lierac
                          - Mustela
                          - Nivea
                          - Oenobiol
                          - RoC
                          - Synchroline

                          MEXORYL
                          - Biotherm
                          - Garnier
                          - Lancome
                          - La Roche-Posay
                          - L'Oreal
                          - Vichy

                          Formulations from the same manufacturer may vary with European countries! Also, Vichy, La Roche-Posay, Garnier, Lancome, L?Oreal, Ombrelle, and Biotherm all have the same parent company; some formulations are very similar although the price isn?t. Garnier Ambre Solaire has the best prices.

                          Comments/questions to Barbara Kwiatkowska

                          More on chemical agents

                          'One problem with chemical screens is instability on exposure to UV radiation. Because sunscreens absorb light energy and must then release it in some form, they may deliver UV radiation to sensitive cells. This, in itself, could lead to skin damage. Physical screens that scatter may redirect some UV radiation onto the skin. When exposed to UV light, a sunscreen's active compounds interact with inert ingredients and with each other, as well as with the skin. These photoproducts, which are different from the original sun filter, may be formed by UV-induced breakdown of a sunscreen product?s ingredients and may have a different toxicity profile from that of the original filter.

                          'Certain sunscreen formulations can lose more than half their SPF value after one hour of artificial light exposure, suggesting that degradation on exposure to UV light, or photodegredation, is an important factor to consider when evaluating sunscreens. Generally, octyl triazone, octocrylene, and benzophenone-2 are completely photostable. Octyl salicylate and methyl benzylidene camphor may suffer a slight degredation on illumination. Octyl dimethyl PABA, and isoamyl methoxycinnamate are mostly photstable.

                          'Although oxybenzone is an excellent broad spectrum UVA filter, it rapidly oxidizes when exposed, yielding products that could have damaging or harmful effects. It can also deactivate important antioxidant systems in the skin and may be harmful to the epidermis. In one study, while assessing broad-spectrum sunscreen protection against chronic UVA radiation, researchers observed a paradoxical worsening of skin damage with one product. Upon further examination, another sunscreens was found to induce a marked dermatitis. Biopsies showed that damage from use of these products greatly exceeded that found in UVA-irradiated, unprotected control subjects including clumping of elastic fibers and collagen damage that was not due to UVA exposure. All products tested provided substantial protection from UVB radiation. The UV filter, oxybenzone, was in all sunscreens. The researchers postulated that there might have been an irritating component in the vehicles responsible for the UV-induced irritation. A reasonable explanation for these adverse events is that the oxybenzone in the sunscreen products was not completely dissolved.

                          'It is important to note that chemical and to a lesser extent, physical filters are not able to completely eliminate UV energy, but must convert it to a different form. These conversions may have unwanted effects.

                          'PABA, one of the first UV filters to gain widespread use, appeared to be a good choice because it occurs naturally, but it is known to increase the formation of thymine dimers upon illumination. People genetically unable to repair these DNA defects are more susceptible to skin cancer. Padimate O, a derivative of PABA, does not generate such dimers but does oxidize DNA and produces free radicals that break DNA strands and may harm other cell components. Avobenzone has been shown to generate free radicals upon llumination. PABA generates oxygen radicals readily, whereas benzophenones, such as oxybenzone, and salicylates do not.
                          ...
                          'In another study, after a dose of 20 MED, which is not unusual for a daily dose of UV exposure, absorbance of octyl methoxycinnamate was reduced significantly. In the case of avobenzone, there is often a rapid decrease in UVA absorption leading to unsatisfactory protection in that region, particularly when combined with physical screens. Avobenzone is generally unstable unless certain additives are included in the formulation. Stability of avobenzone can be enhanced by addition of butyloctyl salicylate, hexadecyl benzoate, butyloctyl benzoate, methybenzylidene camphor, octocrylene, diethyhexyl naphthalate, Tinosorb S, and Mexoryl SX.

                          'UVB radiation has only a minor effect on the stability of most chemical screens. It is the UVA portion of radiation that is most damaging to a sunscreen?s ability to protect, and it is most detrimental to the chemical screens that protect in the UVA range.

                          'This inactivation of sunscreens on exposure to UV radiation may be an underestimated hazard to the skin, because the UVA protection from a sunscreen tends to diminish more than UVB protection on exposure to UV light, and this decrease in UVA protection may allow for the formation of free radicals via increased UVA transmission.
                          ...
                          'Researchers are investigating methods to improve the stability of chemical screens. Placing octyl methoxycinnamate into inert nanocapsules gives marked improvements in photostability: Researchers found that encapsulated particles degraded by 35.3% compared to 52.3% for free octyl methoxycinnamate on exposure to UV radiation.

                          'Some chemical screens may degrade other chemical screens in the formulation. Tinosorb S prevents the photodegradation of avobenzone, even after radiation with doses of up to 30 MED. Since avobenzone is known to destabilize octyl methoxycinnamate, researchers tested the effect of Tinosorb S in sunscreens containing this UV filter combination as well. Here too, Tinosorb S protected both UV filters from photodegrading. Tinosorb S does not appear to be estrogenic and is protective up to 400 nm but has not yet gained FDA approval for use in sunscreen formulations although it is available for use as a washing additive to boost the SPF of clothing. Octocrylene also has a stabilizing effect on avobenzone, and can prevent it from degrading in a formula that includes microfine physical particles, particularly when they are coated to reduce reactivity.'

                          From The Biochemistry of Beauty by Carol Demas & Barbara Kwiatkowska
                          Last edited by saresha; 21-03-2005, 01:56 PM.

                          Comment


                          • #14
                            Sunkiller stockists

                            Basic Beauty Pte Ltd
                            The Heeren, 260 Orchard Road #03-07 S(238855) 6738 0126

                            Jurong Pro Shop
                            9 Science Centre Rd 6560 7370

                            Loke Skin Clinic
                            1 Sophia Rd #04-20 Peace Centre S(228149) 6337 4926

                            Nishino Pharmaceutical Pte Ltd
                            391-A Orchard Rd #B2 Takashimaya S C S(238859) 6735 1226

                            Nishino Pharmaceutical Pte Ltd
                            Meidi-ya Supermarket 177 River Valley Rd S(179030) 6337 5831 (?)

                            Nishino Pharmaceutical Pte Ltd
                            350 Orchard Rd #B1 Shaw House S(23886 6835 3305

                            Sea World Collections
                            No. 50 Tanah Merah Ferry Road #01-09 Tanah Merah Ferry Terminal S(498833) 6542 7730


                            Sa Sa Cosmetics Outlets

                            Wisma Atria
                            435 Orchard Rd #01-14/15 S(238877) 6738 8232

                            Marina Square
                            6 Raffles Boulevard #02-235 S(039594) 6339 1498

                            Parco Bugis Junction
                            200 Victoria Street #01-83/84 S(188021) 6336 9180

                            Great World City
                            1 Kim Seng Promenade #02-39 S(273994) 6238 0195

                            Jurong Point Shopping Centre
                            1 Jurong West Central 2 #02-44 S(648886) 6397 0989

                            NTUC Hougang Mall
                            90 Hougang Ave 10 #03-19 S(538766) 6383 3651

                            IMM Building
                            2 Jurong East Street 21 #01-68 S(609601) 6566 7512

                            Novena Square
                            238 Thomson Road #02-27 S(307683) 6254 3315

                            Clifford Centre
                            24 Raffles Place #01-06 S(048621) 6532 2311


                            Pan-West Pte Ltd Outlets

                            Laguna Main Pro-Shop
                            11 Laguna Golf Green S(488047) 6546 5055

                            Orchid Country Club Pro-Shop
                            1 Orchid Club Rd S(769162) 6759 9211

                            Paragon Shopping Centre

                            290 Orchard Rd #04-20/23 S(238859) 6735 1891

                            Parkland Golf Driving Range
                            920 East Coast Parkway S(449875) 6440 6726

                            Sentosa Golf Club
                            27 Bukit Manis Rd S(099892) 6275 1125

                            SICC Pro-Shop
                            180 Island Club Rd S(578774) 6453 1227

                            Suntec City Mall
                            3 Temasek Boulevard #02-033 S(038983) 6357 5133

                            Tee to Green Showroom
                            59 Jalan Pemimpin L & Y Building #01-03 S(57721 6354 0328


                            Transview Golf Pte Ltd Outlets

                            Singapore Island Country Club
                            240 Sime Rd S(288303) 6461 7443

                            Suntec City Mall
                            3 Temasek Boulevard #02-17/19 S(038983) 6339 3733

                            Transview Golf & Country Club
                            23 Folkstore Rd S(139599) 6872 1167

                            Green Fairways Pro-Shop
                            60 Fairway Drive S(286966) 6462 3833

                            Also:

                            - Gallen Sports at Parkway Parade (near Pastamania and What a Fish)
                            - AMK Bestway (near the starhub booth)
                            - British Essentials at Hougang Central (row of shops opposite Food Land minimart)
                            - Bugis Food village #02-01 tel: 90673731 Boss:Zoelyn Chai
                            - Mustafa Centre
                            Last edited by saresha; 18-03-2005, 09:39 PM.

                            Comment


                            • #15
                              NSC sunscreen comparison

                              Here's a useful (though incomplete) chart comparing various locally-available sunscreens, from an NSC article.

                              Last edited by saresha; 19-03-2005, 08:55 PM.

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