Why you should be using a retinoid
If you want the 60 second version of this post that just tells you what to do, click here to skip to the summary.
There is a cheap, widely available, extremely effective treatment for skin aging that has been around for decades and almost no one outside of dermatologists and beauty bloggers seems to know about it.
It’s called a retinoid. I first learned about their existence a few months ago after looking in the mirror one day and noticing I was starting to get permanent wrinkles around my mouth. Naturally, I wondered if there was anything I could do to fix them.
An ex of mine was a skincare addict and had perhaps the nicest skin of anyone I have ever met. I texted her to ask for advice and she recommended I use a retinoid.
Since I didn’t know what those were or how they worked, I watched a YouTube video. Thus began my 3 month journey down the rabbit hole of skin care product reviews and progress videos. In this post I’ll summarize what I’ve learned.
What are retinoids?
Retinoids are a family of medications derived from vitamin A. In the same way that Ozempic was originally developed as an anti-diabetes drug and later turned out to have a broader set of benefits, retinoids were originally developed to treat acne but turned out to do far more than clear up breakouts.
These effects can be summed up as “improving almost everything about skin”. If we had medications that worked as well for other organs as retinoids work for skin, people would probably live well into their hundreds. It’s actually kind of remarkable just how well retinoids work.
Exactly HOW retinoids work is a little difficult to describe because they seem to do so many different things. Here’s a brief list:
Retinoids increase collagen production
They decrease degradation of collagen within the skin
They protect the extracellular matrix by reducing the activity of metalloproteinases
They thicken the epidermis, which tends to thin as we age
They increase the formation of blood veseels, which makes the skin’s color look nicer and speeds wound healing
They increase the levels of fibronectin and tropoelastin, which makes for firmer, bouncier skin
These things just sound kind of vague and boring until you start to look at people who have used retinoids for a long time. Here’s a screenshot of “Melissa55” on YouTube, a woman in her late 60s that has been using Retin-A (the first available retinoid) for 28 years.
That’s already pretty remarkable on its own (most people in their late 60s do not look like Melissa), but what’s even MORE remarkable is that retinoids can actually REVERSE skin aging after it has taken place. Here’s a couple of before and after pictures of various people who used topical retinoids in a study done back in the 90s.
This is in addition to their intended use reducing acne, where they perform quite well.
Retinoids don’t ALWAYS yeild these kinds of results. You can find many pictures online where people essentially look the same after using them. And you can even find the occasional person whose acne got WORSE with use (though this seems to be pretty rare).
But the vast majority of people see significant visible improvement in the appearance of their skin, and these benefits only increase with time.
Ok, I’m sold. Where do I get a retinoid?
The easiest thing to do here is to just buy adapalene on Amazon. Adapalene is a over-the-counter retinoid which seems to work quite well and generally be well tolerated. You can get enough to apply it to your face every night for about $10-15 per month.
The most potent retinoid is trentinoin, which is the one all the dermatologists recommend. It’s the best studied ingredient for anti-aging, seems to penetrate the skin better and reach deeper layers, and overall seems more potent.
Unfortunately it’s available only by prescription, so if you want it you’ll have to either go to a dermatologist or fill out some forms online. There are a couple of websites websites that do this, but since I haven’t used any I can’t yet recommend one. I’m currently trying out RedBox since it seems to have very cheap prices and a variety of concentrations and tube sizes.
How to use retinoids
The recommended way to apply adapalene or trentinoin is once per day on the face and/or other affected areas. I put mine on before bed. You just need enough to barely cover all areas of the face, which is generally about this much:
The beauty bloggers like to put little dots of it all over their face and then rub it in to ensure even coverage.
Your skins is supposed to be DRY when you apply, so after you wash your face and use your cleanser, towel off and wait a few minutes for your skin to dry before you apply it.
What else should I know about?
When you first start on a retinoid, it will often cause redness, irritation, skin flakiness, and sometimes even a little miniature breakout of your skin.
These preliminary side-effects are worse if you start with too high of a dose, which is why most people recommend that (at least if you’re using trentinoin), you start with a low dose and gradually ramp up. It’s generally recommended you start with 0.025%, then move to 0.05% when you have no more redness or flakiness, then eventually to 0.1%.
I didn’t really follow this advice when I started on adapalene, and as a result my skin was pretty red and flaky for the few weeks of use. But eventually those side-effects disappeared and the benefits remained.
Lastly, you shouldn’t use Retinoids if you’re pregnant or likely to become pregnant.
Use a cleanser
It’s generally recommended that before applying your retinoid, you rinse your face and use a cleanser to remove some of the excess oils and dirt. This is not strictly necessary and you will still see benefits without it, but it’s pretty fast and cleansers are cheap so if you want to go the extra mile this is a good thing to do.
Here’s a link to a good cleanser on Amazon. You can also get a cleanser at any beauty store and at most pharmacies like Walgreens or CVS.
Use moisturizer
Retinoids tend to dry out the skin. You can counteract this by applying moisturizer after putting it on. Here’s what I use (note I am not an expert and it’s very plausible that something else will be just as good for less money).
Use Suncreen
Another thing you should know about retinoids is that it’s heavily recommended that you wear sunscreen on any region of your body where you’ve applied it.
I have to be honest; I don’t really understand why this advice is so universal; research shows retinoids INCREASE the thickness of the epidermis, so theoretically your basal cells should be MORE protected from the sun not less.
But I’ve seen this advice absolutely everywhere, so there’s probably something I don’t understand and you should just follow the standard advice. Also, sunscreen has substantial anti-aging benefits of its own so it’s a good idea anyways. If you want a good brand of sunscreen that doesn’t make you look like a shiny white Mark Zuckerberg on a surf board, here’s the one I use.
That’s pretty much it! I wish you the best of luck on your skincare journey!
TL;DR Version
Retinoids are an extremeley effective treatment for both acne and aging, yet few people use them. They can make your skin look significantly better in the short and long term for $10-20/month and 5-10 minutes of effort per day.
The easiest way to get a retinoid is to buy adapalene on Amazon or from a pharmacy like Walgreens. If you want something slightly more effective and have 15 minutes to fill out a form, you can get a prescription for Trentinoin (a more potent and well studied retinoid) online or through your dermatologist.
Apply just enough to cover your face each night (ideally after using a cleanser), then put on moisturizer. In the morning, put on sunscreen to protect your skin, since retinoids will make it burn more easily.
I have a confusion about retinoids that I haven’t been able to find an answer to:
If retinoids are approximately vitamin A, does this just mean that the average person is very vitamin A deficient? Should they just be eating vitamin A instead? (The best source is probably animal liver.) Surely this would have not just the beneficial skin effects but also lots of other positive effects on the body (surely facial skin is not the only part of the body bottlenecked by vitamin A).
I wonder if people who eat/absorb lots of vitamin A don’t get any marginal benefit from retinoids.
Btw I’ll pay $30 for a satisfying answer to this
Clarification: By vitamin A, I literally mean vitamin A. The compound that can be used without conversion. For example, the compound that is consumed through animal sources like liver.
Dietary vitamin A (beta carotene) is not the active form of vitamin A (retinoic acid), it needs to be converted into the active form by the body’s enzymes. Once retinoic acid is formed, it can bind to the retinoic acid receptor and regulate gene expression.
Retinoid treatment bypasses these enzymes and directly activates retinoic acid receptor signaling. So, eating vitamin A in the form of beta carotene won’t directly increase retinoic acid receptor signaling because the rate-limiting step is the enzymes, but retinoid treatment will. This is also why you can’t overdose on vitamin A by eating carrots.
Does this meet your criteria for a good answer? If not I can explain in more detail.
Hi, thanks for responding. You say:
It is possible to eat the active form of vitamin A, for example through animal sources like liver.
When I said vitamin A, I meant vitamin A (not the compound in plants that can be lossily converted into vitamin A).
So this doesn’t answer the question IMO
The highly active form of vitamin A is isotretinoin, which you can take orally. It has substantial side effects though, meaning it’s generally only used for severe (cystic) acne.
If you want to think of it as a kind of deficiency you can, but then only your skin is deficient in vitamin A (not the rest of your body).
How do we know?
Interesting question! I hypothesize the following:
Vitamin A is distributed throughout the body, so only a small amount actually benefits the skin. The body tightly regulates how much retinol is converted into retinoic acid, meaning that even if you consume a lot of vitamin A, your skin won’t necessarily receive much retinoic acid. Topical retinoids, on the other hand, deliver a concentrated dose directly to the skin, providing targeted benefits that dietary vitamin A alone can’t achieve. Even people with sufficient vitamin A levels in their bodies can still see significant skin improvements from topical retinoids due to their localized effectiveness. Also, consuming large amounts of vitamin A for additional benefits isn’t advisable due to the risk of toxicity.
As a crude comparison, just drinking water doesn’t automatically give you well-hydrated skin, while a moisturizer directly targets your skin’s hydration.
When you say vitamin A, do you literally mean vitamin A, or the similar potential-precursor compound found in plants that is often mistaken as vitamin A? See my other comment.
This is not a good post. I knew that as soon as I saw the title, because there are several different “retinoids” that are very different. Most of them have side effects and a mechanism of action that indicates negative long-term effects. Also some are teratogens. Maybe just read the wikipedia pages for the individual compounds.
The post specifically mentions adapalene which works by “increasing cell turnover” which long-term is presumably a bad thing. It also reduces “keratinocyte differentiation and decrease keratin deposition” which makes skin more fragile, and it increases sensitivity to UV light.
“not a good post” sounds kind of harsh and hostile to me, FWIW.
Leaving out major differences and understating risks is a big problem. But I personally had absolutely no idea that there was even a potential for anything to be remotely this effective for skincare, with or without risks.
Thus, this post is highly valuable for me; and of course I’d do a little research before embarking on something this time-consuming and expensive (daily time cost isn’t the right way to think about it; 10 minutes per day is about 60 hours per year, a week and a half of “full time” work devoted to looking younger every year)
I would prefer the author edit the post to say “there are differences and risks with each, do your due diligence and report back if you want”. But I am still upvoting the post for giving me one solid rationalist clue about the massively complex world of skincare claims.
OK, how about this then:
Is that better?
If the post was just like, “hey, retinoids exist, if you have specific skin issues X or Y (keratosis pilaris, etc) you should consider them, especially the 3rd-generation ones like adapalene, note these side effects and check these articles and then maybe talk to your doctor”—that would be a good post. This is not.
IMO, I am not a huge fan of increasing the burden of evidence for medical claims one way or another. If the author believes that all things considered it’s better for most people to use a retinoid, then I think the post title seems good. If the author doesn’t believe that, then the title would be bad.
I don’t think you improve people’s decision-making in higher-stakes domains by reducing the amount of conversation and information sharing that happens around those topics (though it seems to be a common attractor in norm-space, which I find frustrating, and in as much as I get to set culture on LessWrong about how to handle topics that are often treated this way, I want to put an explicit flag up around “no, it’s fine to openly share advice about high-stakes domains, indeed we probably want to subsidize information sharing about high-stakes domains”).
I asked my dermatologist about skincare routines, and she said, approximately, “There is a cheap, widely available, extremely effective treatment for skin aging that has been around for decades”
Yeah, actually that sounds way better to me. It’s not only nicer but more informative. You really think people shouldn’t be using retinoids, based on your read (it’s more than mine) of the literature?
I really think most people shouldn’t be using retinoids, especially not “retinoids in general”. For people who have certain skin problems, certain retinoids can be worthwhile, but it’s up to them if the side effects are worth the potential (mainly aesthetic) benefits.
I certainly wouldn’t recommend “retinoids”—I’d talk about individual compounds.
My skin is starting to have the problem of looking way older than I’d like :) At the cost of sounding shallow, looks matter for a variety of purposes, so I’d take some measured risks and downsides to get the massive improvements shown in the photos here. I’ll do some research if I get around to it before the singularity :) and report it in a comment on this post if I do anything worthwhile.
Understandable, have a nice day.
I somehow doubt anyone is going to read this and immediately slather a mixture of every retinoid known to man directly to their face (including many which are only available by prescription). If they did, I honestly wouldn’t blame this post. They’re going to either go to a doctor to find out more about prescription treatments, or Google “retinoid cream” and find some over-the-counter retinol that’s safe and has no substantial side effects for most people. This is a perfectly OK introductory post.
I’ve read the article and notice that all the negative side-effects listed are due to issues with oral Retinoids rather than topical Retinoids.
Several of the articles I’ve read indicate that topical retinoids actually DECREASE the risk of cancer, though I agree this is confusing since they supposedly increase cell turnover rates, which should theoretically cause more mitosis-induced mutations to occur. But Retinoids are actually frequently used as anti-cancer drugs.
Google’s AI summarizer says you the mechanism of action is promotion of cell differentiation and inhibiting the progression of pre-malignant cells to malignant cells.
This is correct of course and why I specifically recommend in the post that people wear sunscreen when using retinoids.
No. Topical adapalene has side effects. Also, not sure why you’re capitalizing retinoids.
Anti-cancer drugs generally increase the risk of developing cancer. Cancer preventing compounds reduce the risk of developing cancer.
Most sunscreens contain compounds that absorb UV by breaking into radicals, which can then cause problems in cells. They also often contain endocrine disruptors. These aren’t unavoidable issues but they are common. Sunscreen is also somewhat inconvenient.
I just checked 5 of the individual wiki pages linked from the retinoid page. You suggest they have side effects (together with their mechanisms of action) that “[indicate] negative long-term effects”.
None of the linked pages’ listed topical side effects indicated that to me. Here is the section on side effects for adapalene:
What in here indicates negative long-term effects?
Adapalene is used topically. Wikipedia doesn’t list skin fragility as a side effect but—as you can guess from its mechanism—it is one.
And the mechanism involves increased cell turnover, which long-term tends to either increase stem cell depletion or increase cancer risk. There’s a tradeoff, which is why people don’t just do the thing normally. Maybe your natural tradeoff is wrong and you want to adjust it, but you have to recognize that it exists.
Can you link to a source about the increased cancer risk? Every source I’ve seen on this subject indicates retinoids DECREASE cancer risk, though I agree with you that this doesn’t make much intuitive sense.
Highlighting the existence of different retinoids is good. I have used retinol serums and a tretinoin cream (not at the same time). Retinol products are the most popular in the retinoid skincare category, and are sold over the counter, so reading specifically about them might be worthwhile.
After checking out Melissa55’s YouTube channel, probably worth noting she was on HRT from her 40s until recently, so that might confound the retinoids effect for her in particular.
Anecdotally*, IPL/laser therapy seems to do all of these except increasing dermal capillaries, which it instead reduces. This makes it ideal for people with rosacea or other inflammatory problems, and fair skin (which often accompanies these problems).
*And with a few references: Effective treatment of rosacea using intense pulsed light systems—PubMed (nih.gov)
IPL irradiation rejuvenates skin collagen via the bidirectional regulation of MMP-1 and TGF-β1 mediated by MAPKs in fibroblasts—PubMed (nih.gov)
some studies find no significant effect on collagen etc.; I don’t know what went wrong here besides perhaps too-tan skin: Intense pulsed light photorejuvenation: a histological and immunohistochemical evaluation—PubMed (nih.gov)
The human body uses the amount of UV light it gets to decide how much of the sex hormones to produce.
I notice substantial positive effects from my habit of getting 20 to 30 minutes of strong sun on my bare arms and legs and eyes every other day. The main positive effect is to make me more optimistic and maybe willing to expend effort and endure suffering in pursuit of my goals. (Naturally I avoid getting more UV than I need to keep my sex-hormone levels high.)
People on this site tend to be too dismissive of seemingly-mild interventions like sunlight. “If the goal is to raise the levels of the sex hormones, why not inject the hormones directly?” they might say. Well, I injected testosterone for a couple of years (decades before I started the habit I just described), and I prefer the effects of the sunlight habit I just described to the effects of injected testosterone. The injected testosterone got me into at least one physical altercation and made me expend much too much time and mental energy in the focused intellectual pursuit I was interested in at the time (programming-language design) and had other negative effects (on general metabolism) that are hard to describe.
Most interventions available to us into the functioning of the central nervous system are too strong in my experience, and injected testosterone’s effect on me was too strong. I have a simple model of the brain or at least that part of the brain that controls physiology and mood as consisting of dozens of interlocking feedback loops, and things like injected testosterone alter the equilibrium of too many of the loops too strongly.
Maybe a person wearing sunscreen or high-SPF clothing that covers their arms and legs can get enough UV light to keep sex-hormone levels high through the eyes (as long as they’re not wearing sunglasses) but if so, it would require spending at least 2 or 3 times more time in the sun, which makes it less convenient to maintain a habit of UV exposure to keep sex hormones high.
Note that this is a reply to myself.
Since the comment I am replying to is being upvoted, I will put a little more effort into explaining. “Getting 20 to 30 minutes of strong sun on my bare arms and legs and eyes every other day” is from neuroscientist Andrew Huberman. This effect of UVB light on the sex hormones seems to have been recently discovered; more information here.
That’s an interesting paper! Although it seems a bit confounded—“Because eyes of mice and of human volunteers were not covered, we cannot exclude the possibility that solar/UV radiation to the eye affected the observed sexual behavior.” Which would be interesting if true, suggesting that just being outside and getting UV light in the eyes would be the thing to do. I guess you note this at the end of your first comment.
What do you think about the potential skin aging effects of UV vs the potential health benefits?
https://www.sciencedirect.com/science/article/pii/S1015958423001392 suggests that bright light might be causing the effect, not UV.
Anyone else getting “ask your doctor if Photoshop™ is right for you” vibes from some of those before & after photos?
Hi Gene! As a fellow research-based skincare enthusiast, I’m thrilled to see this discussion here.
I’ve been using adapalene for about two years now, and I’ve experienced all the benefits it’s known for: a dramatic improvement in my skin texture, brightness, and acne.
Adding to the sun protection advice, I think this point is so often emphasized in conjunction with retinoids because reversing signs of skin aging is a major motivation for people using them, and UV radiation is a major factor in breaking down collagen and elastin, accounting for up to 80% of skin aging — this figure is cited by both the Skin Cancer Foundation and the American Academy of Dermatology. While retinoids can help reverse some sun damage, it’s smart to prevent the primary cause of degradation in the first place. In addition to sun avoidance, I highly recommend Korean sunscreens for their advanced cosmetic technology and comfortable textures, and many of them are very reasonably priced.
Thanks for the second expert opinion.
I don’t suppose you’ve looked into the health risks (cancer and whatever else) of either retinoids or sunscreens? I’d want to know before embarking on a daily routine of either one.
Oh, I’m no expert! Just a skincare nerd who loves research-based information. I apologize if my wording was confusing.
I’m not quite sure why there’s so much concern in the comments. Yes, oral retinoids, such as Accutane, do carry significant health risks for humans, but that’s not the focus of this post. While high doses of oral retinoids have been associated with an increased risk of cancer in some animal studies, these studies typically involve doses much higher than those used in topical treatments.
When it comes to topical use, only trace amounts are absorbed, with adapalene having the lowest (<0.25 ng/mL). I tried really hard to find evidence of health concerns associated with topical retinoids, but they seem to be limited to skin irritation and a small potential risk of birth defects during pregnancy. In my opinion, adapalene is the best overall—it’s more accessible, less irritating, has additional anti-inflammatory benefits, and is more chemically stable than tretinoin while offering comparable results.
As for sunscreen, you’ve opened up a whole can of worms there, haha! I’d recommend checking out Dr Michelle Wong, aka Lab Muffin Beauty, who is a fantastic cosmetic chemist with great knowledge on myths like hormone disruption and on retinoids as well. You can find her at https://labmuffin.com/ or on YouTube. I can imagine you’re a busy man. If you have specific questions and my comment gives you a good feeling about my standards, feel free to ask – I’d be happy to look them up for you.
But to quickly summarize, there’s tons of misinformation out there about the dangers of sunscreens that’s not at all in line with the scientific consensus, made worse in the recent years by the “clean beauty”
marketing / corporate opportunismmovement. Sunscreens are rigorously tested and have huge safety margins (at least 100 times higher than the No Observed Adverse Effect Level or NOAEL), which take into account absorption through the skin and potential endocrine and other long-term effects.That’s extremely helpful, thank you!
Sharing my experience here:
VERY white skin, prone to dryness.
Had been on a cleanser+moisturizer combo before going to sleep for most of my adult life. Very liberal use of sunscreen.
Came across some research on different retinoids, started with a medium strength retinol serum (The Ordinary 0.5% Retinol Serum in Squalane) before moving to a higher strength retinol serum (The Ordinary 1% Retinol Serum in Squalane). Three drops on a dry skin after using a cleanser, one to each cheek, one to my forehead, spread evenly. Moisturizer applied after letting it settle for around 10 minutes.
I chose a cheap product ($9.99) because by default I’m quite distrustful of the beauty industry, and assume that simple and cheap is probably good as long as it has the active ingredient that I want.
I chose to start with the 0.5% strength and not the 0.25% for the same reason. My skin was kind of irritated for the first few days, but could handle 0.5% just fine. I moved to 1% in around 1.5 months after using 0.5% daily.
After roughly six months of using a retinol serum, I moved to a prescription tretinoin cream. Retinol already had quite a big effect, and I’m not sure using tretinoin is that big of an additional difference, at least for me. I do find using a cream easier than a serum, though.
I tend to favour simple and cheap products that have an active ingredient that have at least some amount of research backing up its effectiveness, and that are often recommended by dermatologists. Fancier and expensive products seem like snake oil to me, but I could be wrong on this. My intuition is that less products and less chemicals on your face is probably better than more, and I am quite suspicious of the lengthy multi-step regimens some people subscribe to.
I currently use the following:
Before going to bed:
CeraVe Hydrating Facial Cleanser. Comes in a nice pump. I really love how clean it makes my skin feel.
Prescription tretinoin cream.
CeraVe Moisturizing Cream. I chose the tub because it was cheaper per mL. Quite thick, good for dry Winters. They also have a lighter feeling ones, but this is good for my current dry climate and skin prone to dryness.
After waking up:
SPF 50 sunscreen. Re-apply around mid-day.
If you are able to access them, Japanese and Korean sunscreens are amazing. Can’t recommend them enough. They feel like you are not even wearing sunscreen. Leagues and miles ahead of Western sunscreens. This is apparently due to regulatory issues, and the fact that Westerners often ignore the instruction to re-apply sunscreen after a few hours of wear, which has incentivized Western sunscreen manufacturers to optimize for longer lasting (and slimier) sunscreens. Any time friend goes to Japan I tell them to bring me a huge supply of Bioré UV Aqua Rich SPF 50 sunscreen, which is really expensive in the West ($15-30), but really cheap in Japan (like, $4).
I am not sure if you actually need to have sunscreen during days which have a relatively low UV index, but all the recommendations say you need to use sunscreen if you are using a retinol or tretinoin product, so maybe there is a reason for that. I tried researching the reason why your skin might be more susceptible to damaging itself, but didn’t find anything that seemed obviously correct or applicable to topical use of retinol or tretinoin to me.
I felt a bit validated when I saw that Bryan Johnson also uses CeraVe products, heh.
I change my sheets often, so I tend to skip using a cleanser in the morning due to laziness. If you don’t change your bedsheets at least once a week, you might want to do cleanser in the morning as well.
While we’re on the topic of skincare, skin can be very individual in how it reacts to things. I have always had crazily fussy skin and the thing that finally helped a lot after two decades of trying different things was snail mucin. Worth a shot if you’ve never heard of it and have issues. Some people are allergic to it so best to try a drop on your wrist or whatever.
Note that you have to use at least SPF50 sunscreen every day, including during winters, including when it’s cloudy (clouds actually don’t reduce UV that much) if you use tretinoin.
The linked sunscreen is SPF 45, which is not suitable if you’re using tretinoin.
(I used tretinoin for five years and it has had a pretty awful effect on my skin- it made it very shiny/oily. It’s unclear how reversible this is. At some point I learned that it’s a side effect of tretinoin and mostly stopped using it. Some people want their skin to look like that and go for tretinoin to achieve it; for me, it looks pretty unnatural/bad and I am very much not unhappy about it.)
Unlikely to be advice that can be generalised.
SPF is a measure of the reduction of UVB reaching your skin [1−(1/SPF)]
SPF 30 means 96.7% protection
SPF 45 means 97.8% protection
SPF 50 means 98% protection
SPF 80 means 98.75% protection
→ There isn’t much difference between SPF 45 and SPF 50+.
Tretinoin increases sensitivity to UV light, but the biggest factor is still the underlying sensitivity of individual skin. For some people SPF 30 may be more than enough, for others, SPF 50+ may not be enough for prolonged sun exposure.
Still important to make sure that you’re using broad-spectrum (UVA + UVB) sunscreen, and that you apply it correctly.
(IDK anything about the underlying contingent facts, but:
there’s a large relative difference between .967 and .98; almost half as much distance to 1. If exposure is really bad, this difference could matter.
If there’s a damage repair mechanism with something like a rate of repair, that mechanism can either be overwhelmed or not overwhelmed by incoming damage—it’s an almost discrete threshold. )
For sure, but that leads to much more individualised advice of the form “If you’re fine to be exposed to sun for up to 2h with SPF 50, you should not expose yourself for much more than 1h with SPF 30”. The quoted section makes it seem like “You’re fine as long as you wear SPF 50+ sunscreen, but SPF 45 just won’t cut it.”, which doesn’t generalise for most individuals and their level of sunlight exposure.
Why is sunscreen more important when using tretinoin? What happens when you don’t?
The skin is much more susceptible to sun damage. Epistemic status: heard it’s from a doctor practicing evidence-based medicine, but haven’t looked into the sources myself.
It is true that cloud cover doesn’t reduce UV as much as one might think, certainly. But there is a *huge* difference in UV levels between Winter and Summer in Northern Europe. Appopriate levels of sun-cream cannot plausibly be the same regardless of time of year. Time of day also makes a huge difference; if you’re not going outside within 2-3 hours either side of the zenith (in theory noon; in practice moves up to 2 hours off this depending on exactly where you live, local time zones, and daylight saving), you can mostly forget about sun-cream.
There’s certainly a huge difference in the UV levels between winters and summers. Even during winters, if you go out while the UV index isn’t 0, you should wear sunscreen if you’re on tretinoin. (I’m deferring to a dermatologist and haven’t actually checked the sources though.)
This needs more emphasis. Retinoid signaling is very important for embryonic development, so excess retinoids will really mess up your baby.
Not a critique of retinoids but your post is not extremely convincing, I’ve looked into anti-aging anti-wrinkle cosmetics and the world of products is filled with marketing speak. Reading your post it seems no different from frontpage Google blogs for retinoids or skincare or supplements. Seeing those before and after pics is surprising on a site that loves talking about RCTs and statistical power! But it’s hard I’d like to challenge anyone to try googling “vitamin C wrinkles” and see if you can make a conclusion or understand which form or preparation is most effective if at all. Niacinamide, Ha, Ginseng, squalene, vitamins, caffeine… they can’t all work can they?
Cosmetics/health stuff marketing is the name of the game here, just slap a bunch of cheap actives into a bottle and your brand and budget will carry you.
I was unable to come to firm conclusions or cut through blog spam / marketing speak, I personally chose to go for “peptides” (aka Matrixyl, matrikines).
It has been studied to aid wound healing. And this study in Molecular Pharmaceutical, a journal on drug delivery instead of skincare/aging/cosmetic, seems proper https://pubs.acs.org/doi/abs/10.1021/mp300549d
The first Matrixyl 3000 is patented/licensed by it’s inventors (Sederma/Croda), which makes me believe it’s ‘moat’ is its efficacy/trade secret compared with large cosmetics companies who’s competive advantage are marketing/brand. The are a ingredients supplier to these companies, since they are B2B they aren’t in the marketing game. There are also several similar newer competing ‘peptides’ that companies have spend R&D on
For an active ingredient, it doesn’t seem the trouble to make compared to many of the simpler ones if it didn’t work. It’s a triple amino acid that is later palmitoylated to increase topical absorption. That’s is just a guess of course, but Palmitoylated-KTTKS doesn’t roll off the tongue or look nice on a bottle
Even though they are licensed, they arent much more expensive than high end products with cheaper/ineffective actives. Anecdotally, my skin feels more supple. I have no idea which of the peptides works best
There’s plenty of scientific evidence for the effectiveness of topical retinoids, going back several decades.
Thanks, this is interesting
I was wondering, do retinoids work as an acute treatment as well? I sometimes have annoying acne spots in various places, but I don’t feel like preventatively slathering my whole body in the stuff
Hard to say. Retinols are recommended as a preventative. Though incidentally I have noticed acne fading much faster after using them. I suspect this is because they speed up the healing process of the skin.
No, retinoids work by normalizing skin function and usually take at least a few weeks of consistent use to show results. If you need an acute treatment, consider benzoyl peroxide or acids like AHA and BHA.
If you would like to buy Differin gel in a country where it is not over the counter such as the UK, you could buy it on iHerb. It is a US site which ships to other countries, I got some Differin gel from there shipped to the UK and it was less painful than figuring out how to get American Amazon or Walmart to ship abroad. But it is more expensive than the Amazon link OP provided, so I guess this is more of a thing if you want to try some out and see if it works for you with as few effort as possible (although beware that it doesn’t work immediately, you will probably have to wait a couple months to start seeing results).
Just a detail : Haven’t retinoids been discovered when looking for cancer treatments? I thought it was the origin story behind isotretinoin.
According to Claude they were first studied for cancer but the first actual FDA approval was for acne.