Mineral Sunscreen SPF 50 PA++++

Details

One UV filter, zinc oxide at 24 percent, for reactive skin, for skin just off a facial or a peel, and for children over three. Sixteen ingredients, all below with percentages. SPF inflation is the sharpest cheat in Indian personal care, and it is sharp because a sunscreen that under-delivers is a burn the customer cannot see coming. Market surveys here have repeatedly found labelled SPF not being met. So here is the whole test result rather than the number off the front of the pack. In vivo SPF to ISO 24444, on human volunteers, ten subjects: mean 52.4, which labels as SPF 50. UVA measured as persistent pigment darkening in vivo to ISO 24442: UVA-PF 17.8, which is PA++++, and 17.8 divided by 52.4 is 0.34, above the one third of SPF that a broad-spectrum sunscreen is supposed to hold. Critical wavelength 380 nm to ISO 24443. SPF alone says nothing about UVA, and UVA is the half that ages skin and goes through window glass, so all four figures belong on the page together. The filter load is the second half of the story. A pure zinc formula reaching a tested SPF above 50 has to sit near the top of the permitted range, and 24 percent is one point under the 25 percent maximum. This is exactly why so many mineral sunscreens that claim SPF 50 carry 12 to 16 percent zinc and do not reach it. If a mineral sunscreen does not print its zinc percentage, the percentage is the reason. And the number nobody prints: the rating assumes 2 mg of product per square centimetre of skin. Almost nobody applies that much. Studies of real use find 0.5 to 1.0 mg per sq cm. Protection does not fall in proportion, it falls roughly as a power, so at half the dose you get roughly the square root: SPF 50 applied at 1 mg per sq cm behaves like about SPF 7, and at 0.75 mg per sq cm like about SPF 4.3. Face and neck are about 600 sq cm, so 2 mg per sq cm is 1.2 g, which is two full finger lengths or a level third of a teaspoon. A 50 g tube used properly is 41 applications, about six weeks at one a day. If a tube of sunscreen lasts you six months, you are not applying 2 mg per sq cm and you are not getting SPF 50. This and the daily sunscreen fluid are a real choice, not a good one and a worse one. Take this one if your skin is reactive, if organic filters sting your eyes, if you have just had a peel or a facial, if it is for a child over three, or if you will be in water, because this is the one with a water resistance figure. Take the fluid if a white cast will stop you wearing sunscreen at all, and particularly on deeper skin tones, because the sunscreen you actually wear is the one that works.

• Full INCI, in descending order: Aqua, Zinc Oxide, Caprylic/Capric Triglyceride, Coco-Caprylate, Glycerin, Cetearyl Alcohol, Polyglyceryl-6 Distearate, Silica, Isostearic Acid, Sodium Chloride, Phenoxyethanol, Tocopherol, Bisabolol, Xanthan Gum, Ethylhexylglycerin, Citric Acid
• With percentages: Zinc Oxide 24.0, Caprylic/Capric Triglyceride 10.0, Coco-Caprylate 6.0, Glycerin 5.0, Cetearyl Alcohol 3.0, Polyglyceryl-6 Distearate 2.5, Silica 2.0, Isostearic Acid 1.5, Sodium Chloride 0.8, Phenoxyethanol 0.7, Tocopherol 0.5, Bisabolol 0.5, Xanthan Gum 0.3, Ethylhexylglycerin 0.1, Citric Acid to pH, and Aqua is the balance at 43.1
• The 1 percent line falls after the isostearic acid
• Non-nano, and that word is measured rather than asserted: median particle size 210 nm by laser diffraction, with 3 percent of particles below 100 nm by number, against the 50 percent threshold in the EU nanomaterial definition
• Water resistant 40 minutes, by the ISO 16217 immersion procedure, two 20-minute immersions, with 44.6 of the 52.4 SPF retained, which is 85 percent
• Measured pH 6.8. Zinc oxide is amphoteric and dissolves in acid, so a zinc sunscreen cannot be built at skin pH and any that claims 5.5 is worth a second look
• No oxybenzone, no octinoxate, no octocrylene, no organic filter of any kind
• No fragrance, no parfum, no essential oil, none of the 26 EU declarable components
• No parabens, and no MIT or CMIT behind them. Phenoxyethanol 0.7 percent with ethylhexylglycerin 0.1 percent
• No alcohol denat, no dyes, no silicones, no tint
• Honest trade-off one: it leaves a white cast. At 24 percent zinc it cannot not. On light skin it settles in 10 to 15 minutes to near-invisible; on Fitzpatrick IV to VI it stays as a faint grey-white and it does not go away. Warming it between the palms and pressing it in helps and does not solve it
• Honest trade-off two: at 24 percent zinc plus 2 percent silica this is a thick cream that takes real effort to spread over 1.2 g of application. It is not a product you will enjoy putting on in a hurry
• Honest trade-off three: it is untinted. A tint would hide the cast and would also mean matching skin tones, which is a different business, and one product cannot be both honest about the cast and free of it