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#skincare science
I always get so confused about the difference between mineral and chemical spfs. Which one is better long term?
image

two in one response! i’ve talked about mineral vs. physical sunscreen before, but i’ll restate and summarize it all here.

organic filters, aka chemical filters

these are kinda-complicated molecules that are capable of absorbing the energy of UV rays and dispersing it through heat. there’s a big array of these molecules, and new ones keep being created with better absorption profiles. USA-made sunscreen, however, does not use more modern organic/chemical filters (find out why here); for this type especially, it’s best to opt for european and asian brands.

pros:

  • modern chemical filters offer better UVA protection than mineral filters. UVA radiation is the more dangerous one in the long one, being responsible for skin cancer as well as playing a role hyperpigmentation disorders and visible signs of aging (wrinkling, sagging, sun spots, etc)
  • their formulation properties mean that chemical filters are more pleasant and cosmetically elegant to use, which can help you use the necessary amount to achieve the labelled spf (spoiler alert: you need a lot more than you think)
  • newer chemical filters have optimized stability and so they need to be reapplied about as often as mineral sunscreens
  • little to no white cast, POC-friendly!

cons:

  • some people with skin sensitivities react poorly to organic filters and need to use mineral ones instead
  • older chemical filters (the sort that is still used in USA-made sunscreen) were less stable and broke down after a couple hours, requiring frequent reapplication; as i’ve mentioned, this is not the case with newer filters available in other markets

mineral filters

these are simple mineral particles, almost always titanium dioxide and zinc oxide. these minerals reflect some of the UV light (thanks to their white cast), and absorb some of it too.

pros:

  • they are better for individuals with specific sensitivities to common organic filters

cons:

  •  mineral filters create a strong white cast that is especially problematic for brown and black skin — novel nanoparticle versions can help improve these issues greatly, thankfully, but these are still not yet as well researched and so regulation still holds this area back somewhat
  • they are generally thicker and less pleasant to apply, which leads you to applying less than you need and thus being less protected
  • they are worse at protecting you from UVA rays, which as we’ve seen is something that’s rather important
  • they are also not ‘set it and forget it’: both chemical and mineral sunscreens require reapplication after some hours — fewer if you’re out in the sun and actively exposed to water or sweat, more if you’re sitting still and indoors

a note on coral safety because i know this question will be asked again: according to current scientific evidence, all sunscreen is okay to wear in terms of reef ecosystems, unless you’re travelling to / swimming in areas near the reefs themselves, causing the local concentration to rise disproportionally due to currents and high rates of tourism in these areas. everywhere else, you’re fine — the effect is absolutely null at a global scale with the dilution in a planet’s worth of ocean water, and you should be more concerned with the effects of bleached industrial and agricultural substances.

and because i also know i’ll get asked again, here are my sunscreen recommendations for both categories!

lastly, a final reminder: you need to be wearing a minimum of SPF 30 broad-spectrum sunscreen every day. it’s the most basic step of skincare, and the one that’ll yield the most long-term benefits!

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💜 Oils that help skin barrier repair
Sunflower seed oil
Safflower
Argan
Coconut
Borage
Jojoba
Oils rich in linoleic acid (high linoleic:oleic acid ratio) are wonderful for preventing transepidermal water loss and aiding in barrier repair.

💜 Oils with anti-inflammatory effects
Shea butter
Rosehip
Jojoba
Safflower
Grape seed
Coconut
Sunflower seed
Argan

💜 Oils with anti-oxidant effects
Grape seed
Coconut
Jojoba
Rosehip
Shea butter

💜 Oils that may help skin aging
Jojoba
Rosehip
Almond
Oils rich in triterpenes or polyphenolic compounds can, to varying degrees, fight off free radicals and combat aging.

Reminder: Essential oils can be incredibly sensitizing. They should be avoided by those with sensitive or damaged skin.

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I heard US sunscreens really suck compared to European and East Asian ones

true! to put it simply, the USA regulates sunscreen as a drug, which implies a really strict approval procedure for new actives (UV filters), which can take a decade or two to be allowed in the market. this really slows down technological innovation, and US sunscreens are often effectively 20 years behind the rest of the world: meanwhile in europe, where sunscreens are regulated as cosmetics, the UV filters simply have to be approved into a positive list of allowed filters and they can be incorporated into products much more quickly. i confess i’m not too familiar with regulations in asian countries, but i must assume they’re no stricter than the european ones, as they have an even higher rate of innovation in the area.

another thing that makes asian sunscreens in particular more advanced is that they’ve been doing them for longer than western countries. while in the west a tanned look has been very glorified for decades and only now are we waking up to the hazards of sun exposure, asian countries (due to their cultural beauty standards, which can be colorist and problematic, yes, but we are discussing things from a health & safety viewpoint) have always sought to fend off the sun, and you’ll see a much higher prevalence of large hats and sunglasses, long gloves, shawls, parasols, etc. among their population, as well as a much more ingrained habit of sunscreen usage. therefore, since it’s so commonplace, competition has driven innovation and very high quality products are available at very affordable prices in the k-beauty and j-beauty markets. this is why most of my sunscreen recs are from asian brands, and the rest from european ones. online shopping makes it easier to get a hold of these brands even in other areas of the world.

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hi ieva! this might be too broad of a question, but do you have any thoughts on Dr. Bronners soaps? I mainly use the bar soap now and then (especially in summer, it seems to help my oily face then) but I trust your opinion

i never used them as they’re not a thing where i live (not that i know of), and in general i avoid most standard bar soaps (for facial use, anyway). here’s why.

a quick google search tells me that the dr. bronner’s pure castille bar soap pH is about 10. that’s very alkaline compared to our skin’s pH (between 4 and 5 according to most studies). now, lisa bronner defends this on her website saying the pH reduction effect of a cleanser on the skin has more to do with its stripping action than with the pH of the product itself. what she fails to acknowledge is the existing research pointing towards a correlation between the use of higher pH cleansers and acne, for instance, as opposed to a lower incidence of breakouts with the use of low-pH syndet bars.

whether this is due to the pH of the products or due to the comparative mildness or harshness of the cleansers, the fact remains that newer formulations with syndets are preferrable to classic bar soap based on current evidence.

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Was reading one of your other posts and was interested in more information about The Purge period. I am using a new prescription product and my face was looking great until now which is about my 2nd/3rd week using it.

prescription products can behave fairly different from standard cosmetics; consulting a medical professional to ensure this is normal and expectable is likely to be the best course of action. some products like prescription-strength retinoids can have quite an extended purge period, but again, i am not a dermatologist and so i cannot really give any input on whether that is normal purging or not.

when it comes to regular, OTC skincare and purging, it should never happen with certain ingredient and product types:

  • surfactants and other ingredients in cleansers
  • emollients, humectants and occlusives in standard moisturizers
  • UV filters in sunscreens
  • technological ingredients (consistency modifiers, pH adjusters, preservatives, stabilizers)
  • aesthetic ingredients (fragrances and colourants)

when you may expect some purging is when you bring in the big guns, that is to say, products that are much more active-laden and that stay on your skin for longer. these ingredients especially are prone to giving people a rough time for the first month or so of use, with an intensity of effects that is proportional to their concentration:

  • retinol and derivatives
  • vitamin C and derivatives
  • exfoliating acids (AHAs and BHAs especially)

they are also, in my opinion, the most effective skincare ingredients that can benefit essentially any skin type, and therefore, despite the purging, they are worth introducing into your routine; to avoid or minimize purging, introduce them gradually, starting with a low concentration, only once or twice a week, and one product at a time.

and as always, if you’re reacting to OTC skincare (again, this does not necessarily apply to prescription products) for more than 4-6 weeks with no signs of improvement, it’s not a purge, it’s a breakout or allergy and you should try to figure out what product you are reacting to and discontinue its use.

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hey! could you suggest more skincare blogs to follow! I really love yours but I can't find any similar ones on the platform. thanks! :)

i’ll re-enumerate these favs, i’ve answered a similar ask previously but i’m always happy to re-shout out lovely folks from the skincare community around here!

@skincarejesus @skincarehoney @skincarelair @sundayskin @k-skincare @geekbeautysquad @kbeauty-dailyblog @korean-skincare-for-dummies @skincaretipsforyourtwenties @skinknowledge @idontskincare @skincarestudies @still-glows @transcendentskincare @peonies-and-nettle @cloudskincare

beyond tumblr, i also recommend the instagram accounts of @theecowell @kindofstephen @labmuffin @chemist.confesions @sciencebecomesher @liahyoo @gothamista @james_s_welsh @skinchemy ! lab muffin, gothamista, james welsh, liah yoo and the eco well also have yt channels if that’s your thing.

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