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Which skincare products are evidence-based?
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7022I did a bunch of research on this a while ago, here are my high-level conclusions:
- This video is worth watching: Ali Abdaal’s “My evidence-based skincare routine”
- Sunscreen and retinoids get you almost all the way there.
- Sunscreen:
- Wear it on your face everyday.
- Most sunscreen feels horrible and slimy (especially in the US where the FDA has not yet approved the superior formulas available in Europe and Asia).
- The best is Elta MD (UV Clear Tinted Face Sunscreen, SPF 46 Tinted Sunscreen with Zinc Oxide). It’s expensive, but it feels fine on your face, and so you’re more likely to actually use it. And since it’s only going on your face you only need a little bit so it lasts a while.
- Retinoids (vitamin A):
- Retinols are the diluted form of retinoids that you can buy over the counter. They are basically too weak to do much, probably not worth your money.
- The exception to this is adapalene, a new-ish synthetic retinoid you can buy over the counter such as in the form of Differin gel. Adapalene seems to be effective and less irritating than other retinoids, but has mostly been studied for acne rather than anti-aging, so there’s just less evidence at the moment. Definitely a good place to start though.
- Tretinoin is the form of retinoid that is best known for anti-aging. It’s only available with a prescription, but it’s easy to get one. You can either ask your doctor for a referral for a dermatologist, or you can use an online service like Curology or Dermatica, where you send photos, then they create a custom skincare formula that they send you every month - make sure to say you want it to include tretinoin. I use Dermatica and am very happy with it.
- You have to ramp up slowly with tretinoin to avoid skin irritation. If you use Curology or Dermatica they will gradually increase your concentration over time so you don’t need to worry about it. The max they go to by default is 0.05%, but I asked to go up to 0.1% when I was ready.
- Only use retinoids at night since they don’t play well with sunlight.
- A bit of irritation at first is normal (in fact, some say if you don’t experience *any* irritation your retinoid is not strong enough). You can manage this by using it only every other day, or layering it with moisturizers.
- It takes about 6-8 weeks of regular use to start seeing benefits. I've been using it for over a year and I cannot believe how much better my skin is now compared to before I started.
- Other stuff that may be worth trying (but I am less confident in, and is probably dwarfed by the effects of sunscreen + retinoid):
- Niacinamide: A form of vitamin B3, benefits include minimizing pores, evening skin tone, and reducing signs of aging.
- Ceramides: Lipids that occur naturally in your skin and help keep the skin's barrier healthy. Adding more can help restore moisture and prevent irritation.
- Vitamin C: An antioxidant that can protect the skin from damage, brighten it, and stimulate collagen production. Works best at a lower PH so good to use alongside an acid.
- Salicylic acid: A chemical exfoliator that unclogs pores, reduces inflammation, and is antimicrobial (avoid physical exfoliators (e.g. with microbeads), they can damage the skin).
- Hyaluronic acid: Retains moisture, keeps skin plump.
- Moisturizers are worth using, but not the fancy ones.
- CeraVe Moisturizing Cream is cheap and great, you can use it on your face and body. It contains hyaluronic acid and ceramides, it’s fragrance free, and non-comedogenic, meaning it won’t clog your pores.
- As far as I can tell there’s no need to use a separate eye cream, it’s a marketing gimmick. A gentle, rich moisturizer like the CeraVe one is perfectly fine. Just wear sunscreen and sunglasses to help reduce eye wrinkles.
I feel *so* pedantic making this comment — please forgive me — but also:
CeraVe may have degraded in quality when they were purchased by L’Oréal and potentially changed the source of the fatty alcohols in their formulation. Fatty alcohols that have been sourced from coconut are more likely to cause skin irritation than those that have been sourced from palm. Plus, retinoids can actually push these fatty alcohols deeper into the pores for the ultimate backfire effect. My source is u/WearingCoats on Reddit, who runs a dermatology practice and does product consulting for drugstore brands. She's another one of my favourite resources; I recommend running a search on her posts if there's something specific you're interested in learning.
In general, you don't want to use a moisturizer that is heavy or occlusive over retinoids. It could make the treatment more effective than intended, which might compromise your moisture barrier and contribute to irritated skin. Cetaphil may work better for you if you're going down that route. I personally own a variety of moisturizers, which I rotate depending on what else I'm using on my face, and the season.
This is a very fine point and nobody asked, but ...
3
Very helpful, thank you for the extra detail!
- It takes about 6-8 weeks of regular use to start seeing benefits. I've been using it for over a year and I cannot believe how much better my skin is now compared to before I started.
Just wondering if you could expand on just what improvements you see? What features or criteria are you looking at and how you have been measuring the changes?
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* I used to get breakouts maybe like once a month, sometimes with really stubborn/painful zits that would take quite a long time to disappear. Now I basically never get breakouts, I think I've had like 2 small zits since I started and they have disappeared quickly. I have not had any big painful ones.
* My fine lines have been reduced, my skin looks and feels smoother and softer
* I had some redness/discoloration in some areas which has been reduced a lot - no longer needs to be covered with makeup
Dermatica prompts you to send them photos every few months so they can check how your skin is reacting, but it's also convenient because you can look back and see the improvement.
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Has anyone tried Visia skin analysis to get feedback loops on skinhealth? (they reveal WAY more than just pictures) The problem with camera images is that visible light doesn't capture fine lines or wrinkles. My skin SEEMS to look as perfect as that of a 12-year old on the outside, but there is some small amount of wrinkling under my eyes that a visia reveals (which is why this thread prompted me to finally get dermatica tretonin)
Collagen peptides also can help increase collagen synthesis and relieve fine lines (it's my biggest pet peeve b/c I can't stand ingesting animal products, and this is the only thing Bryan Johnson will ditch veganism for). And it's really irritating that there isn't more vegan collagen available.
Weird side effect to beware for retinoids: they make dry eyes worse, and in my experience this can significantly decrease your quality of life, especially if it prevents you from sleeping well.
I live and die by hyaluronic acid. It doesn’t create permanent changes AFAIK but makes a massive difference for me day to day — plus or minus 5 years depending.
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Concerning the efficacy of hyaluronic acid (HA) in enhancing skin hydration, I would like to highlight glycerin (glycerol) as a superior humectant.
Recalling the 500-Dalton rule, which postulates that any compound with a molecular weight inferior to five hundred daltons possesses the ability to penetrate the skin barrier, we can provide a framework that elucidates the mechanisms of penetration of both compounds. Notably, glycerin has a molecular weight of 92.09 daltons, while even a low-molecular-weight HA weighs a substantial 50,000 daltons. For comparison, high-molecular HA can reach a staggering 1 million daltons.
Consequently, HA is rendered incapable of traversing the deeper skin layers and confined to the epidermis. Topical HA is potent and can bind to colossal amounts of water, proving to be a stellar humectant. Nevertheless, the hygroscopic nature of HA can be problematic in dry climates: HA can extract moisture from adjacent skin cells, inducing transepidermal water loss.
A thorough examination of the hyperbolic marketing surrounding this compound reveals a propensity to obscure the boundaries of its categorization concerning its weight, thereby precipitating a conflation of topical HA and injectable HA, which in turn yields imprecise buzzwords such as "filler" printed on topical moisturizers. A comparative evaluation reveals that the rejuvenative effects of topical HA, when contrasted with its injectable counterpart, are eclipsed in terms of its ability to enhance skin volume and elasticity.
Now, glycerin, on the other hand, has consistently demonstrated superior results at a more economical price point. The trihydroxylated glycerol molecule is widely regarded as one of the most (if not best) humectants: its small molecular weight allows it to penetrate the skin effectively, which characterizes its ability to retain and attract water molecules, and ensure long-lasting hydration.
The synergistic effect of HA and glycerin may provide enhanced hydratio
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Oh nice! My retinoid formula and moisturizer have hyaluronic acid mixed in so it's hard for me to isolate its effects, but a lot of people seem to find it hugely beneficial
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Nice! Which hyaluronic acid product do you use?
I watched this video and this is what I bought maximizing for cost/effectiveness, rate my stack:
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Nice!! I don't know much about that moisturizer but the rest looks good to me
Regarding sunscreens, Hyal Reyouth Moist Sun by the Korean brand Dr. Ceuracle is the most cosmetically elegant sun essence I have ever tried. It boasts SPF 50+, PA++++, chemical filters (no white cast) and is very pleasant to the touch and smell, not at all a sensory nightmare.
Most sunscreen feels horrible and slimy (especially in the US where the FDA has not yet approved the superior formulas available in Europe and Asia).
What superior formulas available in Europe would you recommend?
What do you think is the strongest evidence on sunscreen? I've read mixed things on its effectiveness.
Seems like the evidence is overwhelmingly in favor of sunscreen, the studies I've seen against it generally seem to not address the obvious confounder that people who tend to wear sunscreen more are also the ones who have a lifestyle that involves being in the sun a lot more.
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I think it is pretty conclusive that sunscreen wearing will improve your skin complexion and smoothness in the long term (presumably the effect is not worth having if you never go outside in sunshine, obv).
Whether it has enough material effect to do anything to your risk of dying from malignant melonoma (which is pretty rare anyway), is more of an open question. It might not be a worthwhile trade-off for everyone.
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It says to reapply every two hours but I... do not do that 😅 I put it on in the morning and would reapply if I was spending time outside. I don't know how important the "every 2 hours" thing is
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I believe it's 2 hours of sun exposure. So unless you are spending all day outside, you should only need to apply it once. I personally apply it once before going to work.
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oh super helpful, thanks!
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Retinoids, which is a big family of compounds but I would go with adapalene, which has better safety/side effect than anything else. It has less scientific evidence for anti-aging than other retinoids (and is not marketed for that purpose), but I've tried it myself (bought it for acne), and it has very obvious anti-wrinkle effects within like a week. You can get generic 0.1% adapalene gel on Amazon for 1.6oz/$12.
(I'm a little worried about long term effects, i.e. could the increased skin turnover mean faster aging in the long run, but can't seem to find any data or discussion about it.)
David Sinclair mentioned in a podcast that he is also a bit worried about the long term anabolic effects of the retinoids. He suggested cycling it, possibly synchronized with other catabolic cycling such as fasting.
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Can you say more? What are "anabolic effects"? What does "cycling" mean in this context?
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A simplistic model of your metabolism is that you have two states:
1. The anabolic state which builds muscle and creates new cells.
2. The catabolic state which tears down dysfunctional structures and recycles your cells.
A common theme in scientific anti-aging is that you need to balance both states and that the modern life leads us to spend too long in the anabolic state (in a state of abundance, well fed, moderate temperature and not physically stressed). Anabolic interventions can lead to good outcomes in the short-term and quick results, but can potentially be bad long-term.
Cycling in this context would mean something like doing it every other day or every other week (what is optimal? probably no one knows). It could also mean timing it when you don't do fasts for those people who do alternate day fasting or other longer fasts. Fasting and calorie restriction would be typically catabolic activities.
80
This post has some useful info:
https://milkyeggs.com/biology/lifespan-extension-separating-fact-from-fiction/
It basically says that sunscreen, ceramide moisturizers, and retinols are the main evidence-based skincare products. I would guess that more expensive versions of these don't add much value.
Some amount of experimentation is required to find products that don't irritate your skin.
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61This is my first time posting to LessWrong! Thanks for asking such an exciting question!
One of my favourite resources is Chemist Confessions. They have a great book that I would recommend as a primer. They often review studies on their podcast and blog, but I'd probably check out the book first.
Stating the obvious, but is it possible for you to see a dermatologist? They might not be trained extensively on the cosmetics side of things, but they'll be able to get you started with a solid routine.
Also, can we please have more threads like this? I think this is the most women I’ve ever seen in one place on LessWrong, like, ever, and it’s really lovely and fun.
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1Thanks for this!
Does it really make sense to see a dermatologist for this? I don't have any particular problem I am trying to fix other than "being a woman in her 40s (and contemplating the prospect of her 50s, 60s etc with dread)". Also, do you expect the dermatologist to give better advice than people in this thread or the resources they linked? (Although, the dermatologist might be better familiar with specific products available in my country.)
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I would also like to recommend the INCI (International Nomenclature of Cosmetic Ingredients) decoder tool: https://incidecoder.com/. It explains the ingredients of your skincare products and points out potential hazards, such as irritancy and comedogenicity. It's easy to use and you have the ability to compare products.
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I watched and read a ton of Lab Muffin Beauty Science when I got into skincare. Apart from Sunscreen, I think a lot of it is trial and error with what has good short-term effects. I'm not sure about long-term effects at all tbh. Lab Muffin Beauty Science is helpful for figuring out your skin type, leads for which products to try first, and how to use them. (There's a fair number of products you wanna ramp up slowly and even by the end only use on some days.)
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'Evidence based' in the skincare industry mostly means a company paid a consultancy to do 'scientific testing.' Very little shows any signs of actual large effect sizes other than blocking UV damage, afaik. Moisturizer does seem to help, especially in low humidity climes. Which moisturizer your skin responds best to seems to be trial and error, ie the detectable/subjective metrics are all we really have. Retinoids are one exception, but come with tradeoffs that I don't fully understand.
I settled on snail mucin as a more natural alternative, but a significant fraction of people have mild allergic reactions to it apparently.
Snail mucin is one of those products that has less evidence behind it, besides its efficacy as a humectant, compared to the claims you'll often see in marketing. Here's a 1-minute video about it.
It's true that just because a research paper was published, it doesn’t mean that the results are that reliable — if you dig into the studies that are cited in ads, you'll often find out they had a very small number of participants, or they only did in vitro testing, or they graded their product based on the participants' feelings, or something like that.
I’d a...
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I know LW is US/ California heavy, but just as a counter to all the sunscreen advocates here, daily sunscreen use is probably unnecessary, and possibly actively harmful, in winter and/or at northern latitudes.
There doesn't seem to be much data on using sunscreen when there's no real risk to skin, but you can find a modelling study here:
"There is little biological justification in terms of skin health for applying sunscreen over the 4–6 winter months at latitudes of 45° N and higher (most of Europe, Canada, Hokkaido, Inner Mongolia etc.) whereas year-round sunscreen is advised at latitudes of 30° N (e.g. Southern U.S., Shanghai, North Africa) and lower ... Using products containing UV filters over the winter months at more northerly latitudes could lead to a higher number of people with vitamin D deficiency."
Although most approved sunscreens are generally seen as safe, there are potential systemic health risks from a few products, some proven environmental harms, a potentially increased risk of vit-D deficiency, and some time/financial costs.
The question of what kind of sun exposure leads to visible skin aging is an empiric one. Saying "We err on the cautious side and assume that an arbitrary value of 0.5 SED could be regarded as an acceptable daily erythemal exposure" does not imply that there's no visible skin aging under that arbitrary value.
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Of course, but there reaches a level of sun exposure at which the marginal increased harm becomes negligible compared to other things that damage your skin (see this meta-analysis - photo-aging is just one component among many), and below that level you're probably actually getting suboptimal levels of UV exposure for skin health (see this article for benefits of UV - from Norway, aptly).
I'd love to see someone try to measure and compare the specific trade-offs, but I strongly suspect that people at northern latitudes should just trust common sense - only wear sunscreen in summer months, and when you're actually exposed to the sun for extended periods.
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An important thing to keep in mind is that cosmetics companies don't necessarily have the money that e.g. pharmaceutical companies do to push large-scale studies on their products, so lack of evidence usually means a study wasn't done, rather than a study was done and found inconclusive.
If you haven't heard of it before, the subreddit 'SkincareAddiction' has some great recommendations for what's evidence-based and what works.
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I would bet that sunscreen dwarfs all other effects in the long run
You mean in a positive or negative way? Harmful? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615097/ , and/or useless? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1447210/
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"Minimize excessive UV exposure" is the steelman to the pro-sunscreen arguments. The evidence against tanning beds demonstrates that excess UV is almost certainly harmful.
I think where the pro-sunscreen arguments go wrong is in assuming that sunscreen is the best or only way to minimize excess UV.
I personally don't have what it takes to use sunscreen "correctly" (apply every day, "reapply every 2 hours", tolerate the sensory experience of smearing anything on my face every day, etc) so I mitigate UV exposure in other ways:
* Pursue a career of work that can be done indoors
* Avoid doing optional outdoor activities during the parts of the day with the highest UV levels -- before and after the heat of the day is more pleasant to be out in anyway
* use sun-protective clothing like UV-proof gloves, wide-brimmed hats, UV hoodies, etc
* choose shady over sunny locations, or create shade with a large hat or parasol
* choose full-coverage swimwear for outdoor recreation
* wear dark colors on hot days, because dark clothing makes it uncomfortable to remain in the sun very long. I'm good at noticing when I'm too warm, so that's my cue to relocate to shade.
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Just flagging that the effect on sunscreen on skin cancer is a separate question from the the effect of sunscreen on visible skin aging (even if both questions are important).
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Has anyone tried OneSkin/does it actually do what it claims? It acts on a mechanism independent from tretonin.
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Surprised to see nobody mentioned Microneedling yet. I'm not skilled in evaluating scientific evidence, but the takeaway from https://consensus.app/results/?q=Microneedling effectiveness &synthesize=on can hardly be anything else than clearly recommending microneedling.
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I'm using Differin and I can add a few more tips that I've heard and can confirm personally: the purging period can last several weeks and you should see improvement after a few months. It's best to do every other day or every few days initially and then ramp up to daily (for me, this helped avoid a lot of peeling). It's best to apply it after allowing your face to dry so that it's not too intense, and many people also prefer to layer it on top of a buffer like a moisturizer, so you would wash, apply moisturizer, wait 20-30 min, and then apply the product. People particularly like to buffer for the area under their eyes.
Also, a lot of people find that their retinol reacts poorly with other "actives" like glycolic acid etc. I don't think you should do them in the same day, and you shouldn't introduce them to your routine immediately with retinol.
Yeah, glycolic acid is an exfoliant. The retinoid family also promotes cell turnover, but in a different way. You'd be over-exfoliating by using both of them at the same time.
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It seems underrated for LessWrong to have cached high quality answers to questions like this. Also stuff on exercise, nutrition, parenting and schooling. That we don't really have a clear set seems to point towards this being difficult or us being less competent than we'd like.
I expect that these are among the harder YMMV questions, where the right answer really does differ a lot from person to person and over time.
In that sense, a think an actually-high-quality cached answer would look like a giant flowchart where you need months of self-experimenting and data collection at each decision point to make an informed choice, and even then the best-available studies will usually give low confidence in the result. And for parenting and schooling, aging is one way, so it's not always possible even in principle to do the needed testing for a given individual.
The LessWrong Review runs every year to select the posts that have most stood the test of time. This post is not yet eligible for review, but will be at the end of 2025. The top fifty or so posts are featured prominently on the site throughout the year.
Hopefully, the review is better than karma at judging enduring value. If we have accurate prediction markets on the review results, maybe we can have better incentives on LessWrong today. Will this post make the top fifty?
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