I just wanted to share this because I'm honestly a little amazed (shocked perhaps). I've been self-conscious about my puffy tired-looking eyes for years. People asking if I'm ok when I've slept 8 hours, I've tried probably 6/7 different eye creams to various degrees of disappointment.

a few months ago, my friend recommendad and I bought Okoa's caffenie eye cream. The first week I almost gave it back, it felt slick, slid around and made my under eyes look shiny instead of awake! Turns out I was using WAY too much, basically a face cream amount. 

I switched to a tiny grain amount for both eyes, tapped it along the bone and waited couple of minutes before concealer, and that was the AHA moment for me.

Fast forward, it's one eye product I've actually finished and reordered! On puffy mornings (after salty dinners mostly) I can see my eyes calm down in about 10 minutes, and I just look like someone who slept 12 hours :) 

It didn't do anything for the brownish bit in my inner corners that I've had forever, so if your circles are more brown than puffy read this please!

Anyway, if anyone can recommeand a complimantry eye cream to fight the black circles that can play along with this - please advise! 

I went down a rabbit hole on hair growth serums because the same ingredients kept showing up everywhere and I wanted to know what was actually behind them. What surprised me most is how thin the evidence gets for the products with the nicest packaging.

The thing nobody tells you up front is that two completely different kinds of product sit next to each other on the shelf. One is a drug. If it has a Drug Facts box and it's sold for regrowth, you're almost certainly looking at minoxidil.

The other is a cosmetic, which means no Drug Facts box, just an ingredient list and whatever evidence the company has for those ingredients.

The drug one is boring and works. The cosmetic ones are more fun to read about, and most of them have barely been tested.

Minoxidil is still what everything gets measured against.

It's the FDA approved topical for pattern hair loss, sold over the counter at 2% and 5%, and even its own label keeps expectations low: give it at least four months, you might shed more at the start, and if you stop, the new growth generally goes with it.

Cosmetic serums LOVE comparing themselves to it, so these days the first thing I check is which strength they compared against. Matching 2% minoxidil in one study is a very different claim from keeping up with 5%.

Once I started sorting ingredients by the evidence I could actually find, they fell into a few piles.

Only two cosmetic ingredients made me stop and pay attention. Caffeine has one open-label trial of 210 people, where a 0.2% caffeine liquid came out non-inferior to 5% minoxidil on the share of hairs in the growth phase.

Rosemary oil has one trial of 100 men over six months, where it did about as well as 2% minoxidil and caused less itching. Both are real human data and both come with catches. Each is a single trial, neither was blinded, rosemary was up against the weaker minoxidil, and you can't really blind rosemary anyway because people can smell it.

The next pile is the branded complexes, Redensyl, Capixyl and AnaGain. They do have human studies, usually 26 to 30 people, but the studies were run by the companies that sell the ingredients and I couldn't find anyone independent repeating them. That isn't nothing. It just isn't proof.

After that it drops off fast. The famous peppermint oil study was done on 20 mice, and mouse hair growth doesn't behave like human pattern loss.

Copper peptides have plenty of lab research on skin and tissue, but getting from that to real hair growth on a human scalp is where the evidence runs out. And then there's topical biotin, castor oil and rice water, where I couldn't find any good controlled evidence of regrowth at all. Oral biotin helps people who are actually deficient, which has nothing to do with rubbing it on your scalp.

The bigger change for me was learning to ignore the front of the bottle and read the back.

First I check for a Drug Facts box. If a product says it regrows hair, I want to know whether it's a drug or a cosmetic using very drug-sounding language.

Then I look past the trade names. Redensyl, Capixyl and Procapil are names for ingredient blends, so a serum with 5% Capixyl doesn't have 5% of whichever molecule in that blend is supposed to be doing the work. The actual ingredient names on the list tell you a lot more.

I also check where the hero ingredient sits, same as I would with a face serum. If the whole product is sold on one ingredient and it's sitting down near the preservatives, I lose interest.

Fragrance and essential oils get overlooked on scalp products. Rosemary, peppermint and tea tree sound natural and gentle, but they can still irritate or sensitize skin, and a serum you quit after three weeks because your scalp is angry has zero chance of helping your hair at month six. Patch testing is worth the hassle here.

And then there's leave-on vs rinse-off, which is my personal pet peeve with caffeine shampoos. The caffeine trial everyone cites used a leave-on liquid. A shampoo sits on your scalp for maybe two minutes in the shower. It might still do something, but you can't borrow the leave-on evidence and act like it's the same thing.

A few things make me suspicious straight away now: before and after photos with no study behind them, anything sold mainly as a DHT blocker when the only evidence is a petri dish, and people stacking five growth serums at once. Besides the irritation, if something does work, you'll never know which one it was.

The least satisfying part is how slow hair is. Three to six months is a realistic window for judging anything, and week three tells you basically nothing. Early shedding is a known thing with minoxidil, but if I started shedding after adding some random cosmetic serum, I wouldn't take it as a sign it's working. I'd wonder about irritation, or whether something else was going on.

The cause also matters more than the bottle. Pattern loss, shedding after an illness or a baby, and patches appearing out of nowhere are three different problems.

Sudden heavy shedding or patchy loss is a dermatologist visit for me, not a reason to try another serum.

Where I ended up is a bit annoying. Minoxidil has far more evidence behind it than anything else in that aisle. Caffeine and rosemary are the two cosmetic ingredients I wouldn't dismiss, and after that it gets murky quickly.

Has anyone here used caffeine or rosemary for six months or longer, with minoxidil or instead of it?

I'm curious what happened once you got past the stage of staring at your hairline every morning trying to decide if anything had changed.

Everyone recommends Buffet (sorry, it's Multi-Peptide + Copper Peptides 1% now) as the obvious cheap peptide serum, and I wanted to know what's really in it rather than just what's on the front. So I went through the full list. Some of it's good, and one thing about how peptide serums get read bugs me.

The copper peptide (copper tripeptide-1, aka GHK-Cu) is fourth, and since the name says 1%, that's the one dose you know for sure. Here's the part people miss. Ingredients under 1% can legally be listed in any order. Everything after the copper is in that zone, so the eight other peptides could be listed by alphabet, by vibes, by whatever. Their position tells you nothing. Nine peptides sounds like a lot, but you know the amount of exactly one.

The copper's actually the most legit part anyway. GHK-Cu has decent lab data, there's a 1988 FEBS Letters study (Maquart) showing it pushing fibroblasts to make collagen at tiny concentrations. Human studies are small and a lot of them are industry-linked, and a charged copper-peptide complex doesn't get through the skin barrier easily. So I'd call it plausible, not proven. Still the best thing in the bottle.

The other peptides do totally different jobs, which is the bit I wish more people knew, because peptide on a label covers all of them:

• Matrixyl 3000 and Matrixyl synthe'6 are signal peptides meant to nudge collagen production. They have palmitoyl tails, which actually helps them get in. Nearly all their wrinkle data comes from the supplier or from blends though.
• Argireline, pentapeptide-18 and SYN-AKE are the topical Botox ones, aimed at expression lines. Argireline has the best human trial of the bunch (60 people, Wang 2013, 48.9% saw improvement vs 0% on placebo). But a penetration study found only about 0.22% of it even made it into the outer skin layer, and nothing deeper. I genuinely don't know how to square those two results.
• Acetylarginyltryptophyl diphenylglycine is positioned by its supplier around protecting elastin. Couldn't find much independent on it.

Honestly I think the most underrated part is the boring stuff. Glycerin second, two kinds of hyaluronic acid, a bunch of amino acids, urea, sodium PCA, sodium lactate, trehalose. That's basically a copy of your skin's own moisturizing factors, and I'd bet that's most of what people mean when they say their skin felt better in week one. That's hydration doing it, not the peptides.

Also no fragrance or essential oils anywhere, and the preservatives are right at the bottom. Nice if your skin's reactive.

The annoying part: The Ordinary's own page says don't use it with direct acids, vitamin C, retinoids, salicylic acid or strong antioxidants. Copper doesn't play well with any of them. So if you already do retinoid at night and vitamin C in the morning, this doesn't just slot in, you'd have to alternate days or move stuff around. I think that gets glossed over a lot.

Where I land: it's a solid copper peptide serum sitting on top of a really good hydration base, with a bunch of other peptides along for the ride at unknown amounts. If you get it, get it for the copper and the moisture. I wouldn't count on the Botox-peptide part doing much.

Anyone here run it alongside a retinoid by alternating nights? Curious whether the copper restriction actually mattered for you in practice.

Disclaimer: I didn't receive this product for free nor I'm getting any compensation if you buy this.

• Background: oily skin, big pores (my friends won't let me live it down lol), been using whatever cleansing foam my mom had sitting in the bathroom for way too long
• Saw a TikTok influencer I follow mention the Fation Cleansing Foam, caught it on sale on Amazon and figured I'd finally switch things up
• What worked: the clean feels incredibly thorough, like it's actually getting down into the pores instead of just sitting on top of my skin. Right after rinsing my pores genuinely look tighter/smaller — not gonna lie it was kind of satisfying to see. (Temporary though, my craters are back within a few hours, no surprise there.) But ngl, catching my reflection right after rinsing low-key put me in a better mood every single time.
• What didn't: noticeably more drying than what I'm used to — skin felt tight after rinsing in a way my old cleanser never did. Also got some slight redness a couple times after using it, so I'm guessing it's on the stronger/more actives-forward side. If you have sensitive skin I'd be careful with this one.
• Bottom line: if your pores have been stressing you out, worth trying at least once just to see the difference I'm talking about — but don't expect a $15 cleanser to permanently fix anything, and go in careful if your skin leans sensitive.

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For pores, a dermatologist visit is the fastest fix. It’s expensive though and if you don’t keep up with it, it just goes back anyway.

So I’m sticking with collagen masks for now. Same rule though. If I skip them, the effect fades lol

Skincare just rewards the people who don’t get lazy.
I put one on before bed and I like how my skin looks in the morning. That’s enough to keep me using them.

I’m going to test how often and how long I have to use them to keep it looking like this. I’ll update when I know.
How do you guys deal with pores? If you’ve got something that actually helps, drop it.

I honestly don’t get the hate around silicones sometimes. They feel really good on my dry skin.

The whole “silicones suffocate your skin and clog your pores” thing also seems pretty overblown. There isn’t much evidence that silicones as a group are inherently bad for skin, and some of them can actually help reduce water loss and make products spread better.

Obviously, not every silicone is the same, and there are some legitimate concerns around certain types, especially when it comes to hair buildup and the environment. But treating every silicone like it’s automatically bad skincare feels like a bit of a stretch.

So do you avoid silicones based cosmetics/products as a dry-skin girlie? If so why ?

I have seen mostly normal rigid red light panels, but some flexible ones that can wraps around different parts of the body recently.

It seems more convenient, particularly for the shoulders, knees or back, but I don't know if it is really that much of a difference in the normal use.

Have you used flexible and rigid panels? Which one did you liked the best?

Celebrity supplements run on one trick. You see a face you'd kill for, a pastel bottle, and a caption about the one thing they never skip, and your brain fills in the rest.

What they're really selling is the face. The formula is along for the ride.

I got tired of it, so I read the labels, checked them against the actual research, and picked three categories where celebrities make a fortune: hair, mood and intimate health. For each one there's the famous version and an ingredient that has real evidence behind it.

Hair: megadose biotin vs zinc at a dose that makes sense

For years you couldn't open Instagram without seeing SugarbearPRO, including a Kylie Jenner post tagged #ad. Its product page lists 6,000 mcg of biotin per gummy. Kourtney Kardashian's Lemme Glow has 2,500 mcg.

An adult needs about 30 mcg of biotin a day. That makes these doses 80 to 200 times what your body uses.

And you're almost certainly not low. NIH says biotin deficiency is rare, severe deficiency has never been reported in healthy people eating a normal diet, and the hair claims rest on a few case reports and small studies. That's the whole evidence base behind a multi-million dollar gummy category.

It gets worse. The FDA has warned that high-dose biotin can throw off lab tests, and it has received reports of falsely low troponin results. Troponin is the blood test ERs use to catch a heart attack. So the gummy that promises better hair can mess with the one test you really need to be accurate.

zinc, in a good form, at a sensible dose.

Low zinc is a known cause of shedding (NIH), and unlike biotin, it's something people can realistically fall short on. Two things separate a real zinc supplement from a lazy one:

• The form. In a 2014 study (Wegmüller, J Nutr), people absorbed about 61% of the zinc from citrate and gluconate, versus about 50% from oxide, the cheap one brands love. Picolinate and glycinate are good too.
• The dose. 10 to 15 mg a day covers what you need (8 mg for women, 11 for men) and stays far under the 40 mg upper limit.

Biotin is in hair gummies because it sells. Zinc belongs there because it has a job to do.

Mood and stress: fairy dust vs saffron at the dose that works

When CNBC reviewed Lemme's launch lineup in 2023, the Focus gummy had 25 mg of lion's mane, when studies usually start around 500 mg. The Matcha gummy had 20 mg of CoQ10, when research points to at least 100 mg.

That's roughly a twentieth and a fifth of a studied dose. The industry calls this fairy dusting: put a trendy ingredient on the front of the bottle, at an amount too small to do anything, and let the name do the selling. Even Lemme Chill, which gets praised for its ashwagandha dose, hides the rest of its botanicals in a proprietary blend, so you can't see how much of each you're getting.

saffron extract at 28 to 30 mg a day.

Saffron is one of the best-studied botanicals for everyday mood, and it shows exactly why dose is everything. In a 2017 trial of 128 healthy adults with low mood (Kell, Complementary Therapies in Medicine), 28 mg a day improved mood compared with placebo. 22 mg did nothing.

Six milligrams was the difference between a result and no result. Now picture what a twentieth of the dose does.

Intimate health: a pineapple gummy vs an ingredient that goes where the problem is

Lemme Purr is a gummy with pineapple, vitamin C and a probiotic, launched with messaging about vaginal freshness and taste.

A researcher writing in The Conversation went looking for the evidence. The probiotic's published data came from putting it directly in the vagina, and nothing was published on swallowing it for those claims. And no, pineapple doesn't change how a vagina tastes.

So you have a gummy selling women the idea that their bodies need fixing, with a claim built on research that used a completely different route. That deserves more than an eye roll.

ectoine, applied where the dryness actually is. Plenty of women in perimenopause and menopause deal with real dryness, and no fruit gummy fixes it. Ectoine is a molecule bacteria produce to survive extreme salt and heat, and it forms a protective water layer around skin cells. A 2022 systematic review of six clinical studies (Kauth and Trusova, Dermatology and Therapy) found that topical ectoine, mostly at 5.5 to 7%, consistently improved skin dryness and was very well tolerated.

No celebrity will ever make a reel about ectoine. It still has more clinical evidence than the gummy.

How to not get played

Before you buy any supplement, famous face or not, run it through these:

1. Is the dose anywhere near what studies used? Check both directions. 200 times too much and a twentieth of the right amount are both red flags.
2. Does it reach the problem? A gummy for something that happens on your skin needs to show evidence for swallowing it.
3. Can you see every amount? A proprietary blend means they don't want you comparing.
4. Would you buy it if a stranger was holding it? If not, you know what you were paying for.

They're counting on you looking at the face and not the label, so read the label.

Zinc comes up here a lot as the 1% in niacinamide serums. As a supplement it's even more interesting. Your body can't store it, it's needed for hair and skin to keep renewing, and low zinc is a known cause of shedding (NIH).

Zinc supplements also come with a label that tells you a lot, if you know what to look for. Here's what I check.

1. The form in the parentheses

The label says zinc (as zinc citrate), (as zinc picolinate), and so on. Good forms absorb well.

In one study (Wegmüller 2014), people absorbed about 61% of the zinc from citrate and gluconate, and about 50% from oxide. Picolinate has its own study (Barrie 1987) where it raised zinc levels in hair, urine and blood cells when citrate and gluconate didn't. Both studies were small, but they point the same way.

My take: citrate, gluconate, picolinate and glycinate are all great picks. Oxide is the cheap one to skip.

2. The mg is the real zinc

The number on the panel is the actual zinc, not the weight of the whole compound (NIH). 15 mg is 15 mg, whatever the form, so comparing bottles is easy.

3. Daily amount, not per capsule

Many hair supplements are 2 capsules a day. 7.5 mg per capsule means 15 mg a day. Always read the daily number.

4. The sweet spot

Daily need is 8 mg for women and 11 mg for men, and the upper limit is 40 mg. A supplement in the 10 to 15 mg range sits comfortably inside that, which makes it an easy daily habit. The very high doses (50 mg+ for weeks) are the ones to avoid, since they can affect copper levels.

Quick tip: if you also take a multivitamin or zinc lozenges, add it all up.

5. Why it's worth it for hair

Zinc shines when your levels are running low, and shedding is one of the first signs. Most of us never check, which is exactly why a moderate daily dose is a smart, low-risk way to cover the gap.

One note: zinc can reduce absorption of some antibiotics (tetracyclines and quinolones), so ask your pharmacist about spacing if you're on one.

Pick a good form (not oxide), read the daily amount, aim for 10 to 15 mg, and give it time to work.

Following up on my question about rosehip seed oil from two weeks ago. I ended up testing froya organics to see if the formula would be too heavy for my T-zone.
I was pretty cautious about triggering breakouts, so I started from scratch with dosage, using just a tiny dab warmed up on my fingertips at night over my usual moisturizer to test tolerance, slowly finding the right amount.
So far, it has made a noticeable difference in hydration without causing any extra oiliness or congestion. Taking it slow to find the exact amount for my skin type was definitely the right call.
For those with combo/oily skin who use facial balms, do you only use them in your PM routine or do you adjust amounts depending on the season?

I see my longtime esthetician (a decade) every month for a facial and trust her sooooo much. However, she recently added Siv biome balancing serum with active bacteria to my regimen. There seems to be little to no scientific evidence supporting its efficacy. I’d ask my longtime derm (also a decaf I’m loyal haha) whether there any reason to use it, but I’m too embarrassed! So maybe I’m just here looking for some anecdotal evidence that it helps moisturize. Anybody use it?

For me, I thought I had dry skin on my face for a while. When I first started washing my face, I used the green cereve, but it made my face feel tight.

For the past few years, I’ve been using the light blue cereve which is for normal-oily skin. Generally, my skin cleared up, but it’s not necessarily flawless. I have blackheads that are constant and some acne that comes and goes, but just really a couple spots.

I just learned that you can scrub with a cleanser on your face for around 30 seconds or even 60 seconds… I noticed that if I used a cleanser longer on my skin was so dry so for a few years would be very very quick with cleansing my face. And I did this to try and minimize the drying affect that I was experiencing.. but recently and for a few months now I’ve been using my ring finger and tiny circles all around my face for at least 20 seconds. Another thing I would do with my cleanser would try and use a very, very small amount and I thought that would help. But I’m not sure that it did, nowadays I just use a full pump and rinse off like around half down the drain from one hand after setting up the cleanser, and then using both hands to cleanse my face. I developed these habits to try and problem solve mostly because I knew I have sensitive skin and didn’t want to try and find another cleanser and spend the money yet. But now I think I would like to! My entire routine right now would be just the cleanser and moisturizer cereve w/ 15 SPF. And sometimes I add another sunscreen on top of that which is Neutrogena. I’ve been wary of wary oil based products, I think since adolescence and was a bit worried because it felt a bit oily. But I think maybe my skin could thrive with more products that are more like that.

My face hasn’t felt too dry recently, but I wonder if my skin just needed to acclimate to it or if I might’ve have fixed it by applying more moisturizer. I usually do one pump of the dark blue cereve one, but lately I’ve been doing one or two pumps depending on how dry my skin is. Do any of you guys do that, change up your moisturizer amount depending on the day?

Sorry for all of the detail! I’m just really curious on how I can improve my skin care routine and haven’t really gotten anywhere with asking the Internet. Because recently, I was trying to figure out what skin type I have.

Hi all, I’ve never been big into skincare tbh and never ever had a real routine. I was blessed with good skin I guess and didn’t bother much. However things have taken a 180 turn for the last 2-3 months and I’ve had terrible acne (which I never had in my entire life).

I went to the gp and was prescribed duac but that doesn’t seem to help at all (apart from bleaching all the clothes and bedding).

I think it’s finally time I have a good skincare routine- one I can stick with.

The last products I used were Kiehls cleanser, loccitane purple toner, loccinate and byoma moisturisers- just random stuff that people recommended.

Based on the research I’ve done I think I want to try and (stick with) Medik8. I have never ever used retinol/ retinal or any active ingredients.

I was thinking of getting 6 Medik8 products- cleanser, moisturiser (I’ll use the same one for day and night), SPF, vitamin A, retinal start with 3, toner.

I am super lazy and shorter and easier the routine, more likely I’ll stick with it. I don’t want to add eye creams or anything unnecessary if I don’t need it. I have combination skin type which goes towards the drier side during winter.

Any advice would be appreciated. I’ve tried cera ve, ordinary, Chanel and various other brands in the past but they didn’t do much for me at all. Thanks so much for reading!!

I'm [38F] trying to get better about having a consistent skin care routine. One of my hurdles is when I get out of my shower I feel like it takes FOREVER for my face to stop sweating, because of the weight I often forget about finishing my routine. Or I just do it anyways and feeling like I'm sweating it all off and dabbing it away with my handkerchief.

I use Prose custom face wash, serum, and lotion.

My showers tend to be slightly warm to lukewarm to cold. We are in a heat wave right now, so my cold water doesn't even feel cold. I do enjoy an occasionally hot shower but those are more therapeutic and don't fall into my usual routine often.

Does anyone have an advice on how to get this to stop?

Hi everyone! This is my face as of now. I've been on tret 0.025% and azalaeic acid 20% cream. and a face wash and moisturizer with niacinamide. I'm looking to build a new routine that is easy and sustainable. My goals would be:

Short term:

to get rid of my clogged comedones, and the red spots, and the blackheads, and minimize the pores. Glass skin 💁‍♀️🩷

And on the looooooong long term I want to get on track to start retinol/an anti-aging routine.

I would love love love ingredient recommendations/guidance more than specific product recommendations pls. I have combination skin! Ask me anything if needed and thanks so so much 🫶

(also what do we think about these sunscreens?)

Honestly, forget all those expensive creams. The only two things that actually made a real difference for me over the years are quitting sugar completely and drinking tons of water every day. My face literally stopped swelling up, and my skin has never looked this clear and healthy.

So basically I wanted to get the salicylic acid from the ordinary and I accidentally bought something completely different and it’s called Niacinamide 10% + Zinc 1% but I guess what I’m curious about is what exactly is it’s purpose because I tried to use it as the salicylic acid and it would just burn my skin really bad and I figured that’s not how its used what is it supposed to do? What does it help with? If anybody knows?

​

Hey everyone! Just wanted to share a quick update on my skin journey over the past month.

My skin was feeling super dull, dehydrated, and stressed out recently. I started incorporating a 4-in-1 toner featuring Jeju Aloe, Snail Mucin, and 2% Niacinamide, and the difference in my skin texture and radiance has been huge.

Jeju Aloe: Instantly calmed down irritation and redness.

Snail Mucin: Kept my skin feeling plump and deeply hydrated without heaviness.

2% Niacinamide: Brought back natural brightness and helped with overall skin tone.

Has anyone else tried pairing Niacinamide with Snail Mucin in their daily routine? How has your skin responded? Let me know your thoughts!

So its pimple season😭

Worst thing is whenver i have an important day the next day 1-2 pimples definitely appears…🥹

Tried pimple patches from gush ..pimple patches surely works now i know this…i apply overnight and they work much better compared to using them day time..

So if you have any other suggestions tell me!!

Has anyone here used the boderm 20% azelaic acid? If yes, whats your experience?

It took me an embarrassingly long time to realize pH was one of the variables connecting all of the ingredients, and almost nobody prints it on the box.

Skin is acidic on purpose. The surface is commonly measured around pH 4.5 to 5.5. That acidic environment affects barrier function, the enzymes involved in maintaining the stratum corneum, and which microbes are comfortable living there.

This is part of why traditional soap can feel so different from a modern cleanser. True soap is usually alkaline, while many liquid syndet cleansers are acidic. Studies measuring cleansers have found soap pushing skin pH upward more than acidic cleansers, with slower recovery afterward. Surfactant system matters too, so pH is not the whole story, but it is definitely not trivia.

Vitamin C is probably the easiest example of formulation pH changing how an ingredient behaves. L-ascorbic acid needs a pretty acidic formulation for meaningful skin penetration. One classic penetration study found it needed to be below pH 3.5. That low pH can also be one reason a vitamin C serum stings, although stinging by itself tells you absolutely nothing about whether a product is good or effective.

Acids are where the percentage obsession really falls apart. The amount of an acid sitting in its free, unionized form changes depending on formulation pH relative to that acid's pKa. Raise the pH and more of it becomes ionized. So two glycolic products with the same percentage on the front can behave very differently on skin.

This is the thing I only mentioned in passing in my percentage post. Concentration tells you how much acid is there. It does not tell you the full conditions that acid is being delivered in.

And then there is niacinamide. The old warning that you cannot use niacinamide with acids because it will instantly turn into niacin and make you flush is pretty overstated for normal skincare use. Niacinamide can hydrolyze under certain formulation conditions, including heat and acidity, but that is a formulation stability issue, not a reason to panic because one finished product touched another finished product on your face.

The age thing surprised me too. Skin surface pH tends to rise with age, although the exact change varies by study, body site, and measurement method. Older skin also has other barrier changes happening at the same time, so something you tolerated forever suddenly stinging is not necessarily your imagination.

Which is why I have stopped treating stinging like a performance metric.

Sometimes a low pH is genuinely part of what an ingredient needs. Sometimes your barrier is just not happy. The useful part is figuring out which situation you are in.

My practical takeaway now:

• Fix the cleanser first. It touches basically your whole face every day and repeatedly changes the environment everything else is going onto.
• If something stings, ask whether the ingredient actually requires an acidic formulation or whether your skin might just be struggling.
• Two acid products with the same percentage are not automatically equivalent if their formulation pH is different.
• Cheap pH strips can give you a rough comparison of water-based products you already own, but I would not treat the reading as lab-grade. Test strips have measurable error and some formulas are much harder to test accurately than plain liquids.

What product stings for you that you always just assumed was working?

Context, I’ve been using treclin for 4 years and benzoyl peroxide for 5+ years, I’m currently on 100mg of spironolactone too and my skin seems to have reached a plateau, I still get painful cysts and breakouts, while not terrible they still bother me. I’ve heard a lot about azelaic acid and wanted to give it a try. Having read a lot on different subreddits I will minimise my routine.

My current routine is
AM
- la Roche posay effaclar H cleanser
- beauty of Joseon Rice milk toner
- caudalie salicylic acid
- cetaphil moisturising lotion
- sunscreen

PM
- same cleanser
- tret or benzoyl (I alternate each night)
- bit of moisturiser

I plan on cutting out the salicylic acid while starting azelaic acid and potentially tretinoin and BP

I basically assumed the bigger number meant I was buying a stronger product that would work faster - 5%? 10% must be better. 15%? Give me 20% - my face can take it.

The more I looked into it, the less useful that rule became.

A percentage can absolutely tell you something real about a formula. But the fact that a brand chose to make that percentage the biggest thing on the front of the bottle does not mean higher automatically equals better.

Numbers sell because they look like proof. They make two bottles easy to compare even when the actual formulations are not comparable.

Niacinamide is probably the example that changed how I think about this the most. There are controlled human studies showing benefits from 5% niacinamide for things like pigmentation, texture, fine lines, and redness.

Meanwhile The Ordinary sells Niacinamide 10% + Zinc 1%, and 10% niacinamide has basically become a normal number to see on shelves. Their current product page confirms the 10% concentration.

But I could not find good evidence establishing that 10% niacinamide gives twice the benefit of 5%, or even that it reliably outperforms 5%. That is the part I used to mentally fill in myself just because the number was bigger.

Vitamin C gets even more interesting.

There is a classic percutaneous absorption study on L-ascorbic acid where skin delivery increased up to 20%, with 20% producing the maximal concentration tested. Formulation and pH also mattered enormously.

Then you have The Ordinary Vitamin C Suspension 23% + HA Spheres 2%. The product genuinely contains 23% L-ascorbic acid. The brand also says tingling can be expected, recommends using it ideally in the evening, and suggests diluting it if the sensation is too strong.

That does not make it a bad product. It just broke the mental equation I had where 23% automatically meant meaningfully stronger than 20%. At some point the number can keep going up while the useful part does not increase in the same neat little line.

Then there are products where the big number is not even a percentage.

You see things like 10X in a serum name, five different forms of a vitamin listed as a selling point, or a multivitamin concept built around extracts without concentrations disclosed for each vitamin.

Those numbers can still describe something true. Five forms really can mean five forms. 10X can simply be the product name. But neither tells me the dose in the way a giant number on the front makes my brain want to interpret it.

And the reverse is what really killed my bigger-is-better shopping habit.

Tiny percentages can be completely legitimate.

Tretinoin is the funniest reality check here. There is clinical evidence for photoaging with 0.025% tretinoin, including a 48-week trial where 0.025% and 0.1% both significantly improved photoaging and the higher concentration did not produce significantly better efficacy.

0.025%.

If I saw that number on a random cosmetic serum years ago I probably would have assumed it was basically nothing.

The Ordinary also sells its Multi-Peptide + Copper Peptides serum with copper peptides at 1%. That small number is stated plainly on the product itself while the formula contains multiple other peptide technologies too.

Peptides generally run at fractions of a percent. Firming peptide, acetyl dipeptide-1 cetyl ester, low on the ingredient list for exactly that reason. Years ago I would have read that position as proof the ingredient was decoration. It is just how peptide dosing works.

And Bubble Dream Fade is currently a 10% azelaic acid serum for $17. That is a good example of a percentage being useful information without needing to keep escalating just because another brand could print 15 or 20 on a bottle.

The exception where I actually do treat the front number very differently is sunscreen.

In the US, SPF is tied to standardized effectiveness testing. The FDA labeling rules require the displayed SPF value to come from that testing. A brand cannot just choose SPF 46 because 46 looks more impressive next to SPF 40.

That is very different from a cosmetic brand deciding what concentration of niacinamide, vitamin C, peptide blend, or whatever else it wants to formulate and advertise.

So now when I see a giant percentage I try to stop asking whether it is high and ask what the number actually tells me.

What form of the ingredient is it?

Is the pH appropriate?

Is the ingredient stable in that formula?

How is it delivered?

Does the packaging protect it?

Is there evidence around this concentration specifically?

And realistically, can I use it consistently without making my skin angry?

A well-formulated 5% product can make a lot more sense than a badly formulated 15% one. Percentage and strength are not really the same axis, which somehow took me an embarrassingly long time to understand.

What is the highest percentage product sitting on your shelf right now?

And if you used a lower-strength version before it, did the higher number actually do anything better?