You’ve probably seen the concept of rebound oil production, or reactive seborrhea:
“shampoos… strip the scalp of its natural oils and cause the scalp to overproduce oil to compensate”
“our skin naturally regulates perfect oil production”
“your skin will have to adjust to producing less oil”
“the oil tells the skin it’s no longer drying out, which helps to control excess sebum production“
This is a very common concept that is….well, impossible. But why do so many oily-skinned people notice less oiliness when they switch to more moisturising products?
Skin can’t sense how much oil is on it
There are lots of systems in your body that operate on something called a negative feedback loop. For example, when your body senses that its temperature is too high through receptors, it will send signals to sweat until the body returns to its normal state (homeostatis). Another example is when your blood sugar is high, receptors in the pancreas detect this and release insulin, which brings the blood sugar level back down.
The problem with applying this is that there isn’t any way for the skin to detect how much oil it has on it. Sebum is produced to a certain level on the skin, and is stopped by the physical phenomenon of surface tension, so you’ll end up with around the same total amount of oil on the skin, whether it’s natural sebum or skincare oil or a combination. The amount of sebum your skin ends up with depends on genetics and hormones – not on how much oil you put on the skin. Skin won’t “adjust” to the additional oil, no matter how long you wait (hence why no-poo simply won’t work for some people, such as me!).
Then why did I get less oily when I switched to a gentler cleanser?
There is a kernel of truth to this myth, and that is the fact that harsh products can sometimes leave you with more oil on your skin…just not for the reasons given. The sequence of events at some point in every oily person’s life goes something like this…
1. See oil on your face
2. Wash it off
3. Goodbye shine!
4. Wait…there’s more oil. Maybe I should wash harder?
(Repeat steps 2-4)
Washing is one of the most traumatising things people regularly do to their skin. Your skin is tough, but it can’t handle being scrubbed and stripped of oil all the time, and if your skin is oily, it’s really tempting to keep trying to wash the oil off. Overcleansing will damage your skin, which could potentially trigger your skin’s inflammatory response – to release the stored oil onto the surface of the skin, where it will sit instead of sinking in.
So it isn’t that more oil is produced – there’s the same amount of oil. It’s that the skin is damaged and the oil ends up in the wrong place.
- You’re noticing your oil more, because you’re seeing it go from almost nothing after cleansing to its normal level, which gives a bigger contrast
- Your moisturiser contains mattifying agents which help reduce the appearance of oil
What’s the difference then?
This means that if your skin isn’t damaged or dehydrated and it’s still oily, then no amount of oil cleansing or no-pooing will decrease your oiliness. Sorry!
But if you’re oily, and you ARE cleansing a lot (more than once a day, or with a foaming cleanser, or you scrub more than twice a week), or you’re seeing the signs of dehydration (tight-feeling skin, oil sitting on parched-feeling skin), you should try switching to a more gentle routine and see if things improve.
Is there anything else I can do about my oily skin?
Yes there is! You can soak up the oil with make-up (powders and primers) or blotting paper. Certain prescription medications can also help, like hormonal birth control, spironolactone and isotretinoin.
Your skin might feel oilier if it’s dehydrated, but if your skin is healthy and still oily, nothing you slap on your skin can change that.
C. Pierard-Franchimont, J. E. Arrese & G. E. Pierard, Sebum flow dynamics and antidandruff shampoos, J Soc Cosmet Chem 1997, 48, 117-122.
“Such a finding confirms the unreality of the so-called reactive seborrhea, in which the sebaceous excretion increases with the frequency of most hair washes… Another study has shown that those shampoos promoting seborrhea were those yielding some irritancy potential on the stratum corneum. The direct relationship between alterations in sebum flow dynamics and subclinical irritation is suggested, although not proven, by these studies.”
37 thoughts on “Do oils make your skin less oily? The myth of rebound oil”
Great article! I have had oily skin for my whole life, and use a very gentle cleanser (no moisturizer) and of course powder & blotting papers. I don’t think I’ll ever try putting oil on my face!
Though weirdly, my skin is MUCH less oilier since I’ve been on a strict low carb diet (elimination diet for allergies). I know it will come back once I reintroduce foods, but I’m enjoying the temporary reprieve!
I also have oily skin and I do like putting oils as overnight treatments (rosehip is great, and thick occlusives like Nivea Creme are so hydrating for me), but during the day it’s a definite no for me too!
There are a few studies on the effectiveness of low GI diets for acne (acne is partly linked to high sebum production) – the research is very new so it’s not very reliable yet, but so far the data suggests that it could work for some people!
I used to believe the whole “skin senses oil” thing as well, and learnt from experience that it’s just not true. As I’ve gotten older, as well as having moved to a drier country, my oil production has slowed up somewhat, and it’s a lot easier to deal with!
I used to believe it too, but it was really confusing how skin could sense oil! I can’t wait til my oil production ramps down when I get older 🙂
I’m finally vindicated! When I was younger, my face and scalp were a grease pit. People would tell me to quit washing my hair every day and my hair would “get used” to not being washed so often and thus produce less oil. Tried more than once and it was always gross! I never overwashed (was too lazy); I just cleaned what I could once a day. Now that I’m older, oil production has gone down, and I can’t say I miss it.
I have the same experience with washing my hair less frequently – my scalp and hair are happiest when I wash once a day!
I can see your point. But from my experience, using oil in my nighttime skincare routine really makes my face significantly less oilier in the morning. The same thing happens with all of my friends, to whom I recommend the oil.
That sounds like the situation I described above – where the skin is damaged from your old routine and the oil sits on top of the parched skin. With oil, your skin is more hydrated, and better able to absorb the oil. It’s like a puddle of oil on top of a piece of cling wrap, versus oil that’s soaked into a sponge 🙂
I thought that back in ye olde days it was determined that sebum excretion regulates itself by surface tension (sebum =/= oil, though). Can you give any sources for studies that suggest otherwise, or do you know if those findings were recently refuted or something?
The only other article I could find on this seems to agree:
I know this doesn’t prove that adding oil makes the skin produce less sebum, as that’s not the hypothesis that was tested (btw, why has nobody tried this? It would seem like an obvious experiment – just pick some oil with a similar surface tension).
But it does suggest there is a way for the skin to “know” what’s on it, even if they just measured excretion and not the actual production (that would probably require a biopsy of the sebaceous glands), excretion still affects how “oily” skin looks.
Maybe it’s just that the produced sebum stays in the sebaceous glands longer if there’s enough of it on the surface. Now is that a good or a bad thing?
Thanks for this! I missed these papers in my searches – I’ll have to amend this post to clarify that you end up with approximately the same amount of oil on your skin, whether it’s sebum or added oils (assuming that oils have similar surface tensions).
But what if it changes drastically depending on what moisturiser you’re using and from week to week or even day by day? I’ve had the same cleansing routine for two years but how greasy I get does change from day to day sometimes and can depend on what moisturiser I use, I have one that feels good but it leaves me a greasy mess by the time I wake up, and if I mix it half and half with another lighter moisturiser it’s much better (trial and error, over and over)?
They all feel fine when applied and for a while after, but some days I become an oil slick and some days nothing much happens, with the same routines? I’m trying to understand because right now, like the last week, my skin has been HORRIBLY oily and I just don’t know what to do really, I haven’t changed anything or been out in the sun or anything like that. I just want to put on makeup and be done with it but right now I can’t because I just look terrible after a few hours, it’s slipping right off my face no matter what I do.
There are other things that can affect how much oil accumulates on your face. Sometimes it’s the water-soluble parts of the moisturiser absorbing or evaporating and leaving the oil behind, it could be changes in your hormones or weather, how much exercise you’ve done…
One thing that might help is the Goss method, which involves putting powder on under your foundation (Wayne Goss has a video on it). You might also find blotting papers handy for soaking up oil from your skin throughout the day without messing up your makeup. Also, do you use silicone-based products? I find that anything silicone-based looks fine and matte at the beginning but slips off my skin after a few hours.
I don’t feel there’s a sense of any of it. My skin fluctuates all the time and I never really change anything apart from the weather changing around me really. And I don’t use much silicone based products but don’t feel that they really impact that much. Everything just slips off just as much, haha (sob).
Ok, this is something I’m living with on an extreme scale. Dermatologists are “evidence based” blind to the evidence on their exam room tables. Hot topic for me, and I’ve spent a couple years researching it (ironically, as it pertains to my dog because he was affected more than me, or so I thought).
The deal is Yeast + Inflammation = Hyphae. Hyphae = invasive fungus. Yeast like Candida is normal, everybody knows candida, everybody has candida. Problems come when it ‘flips’ into it’s other form and grows fungal roots. It took them forever to realize yeast is fungus in spore form (I think….systemic infections of it cause much confusion….) Candida is internal, and on mucus membranes.
Enter Malassezia, another passive local flora on everyone’s skin. External. Systemic inflammation is an overactive immune system, not just for those with HIV and those undergoing chemo, as most family practitioners will tell you). Could be caused by allergies, disease, Lyme, but family docs are not immune specialists so this escapes them. Even dermatologists – I saw 2 of the better teaching derms who also practice and they told me I had “female pattern balding”, “a birth mark”, needed to cleanse gentler, and take tepid baths when shown pics of how beet red my feet turn after a shower. And hormones for greasy face/chest/back. This was all false.
So I went out and bought a usb microscope, plugged it in, and looked at my scalp and pores. Brimming with fungus. Pores sewn shut from fungus + keratin + sebum. It ejected the hairs on my scalp, massive rootball and all, and sealed up the follicles. Same for face, my chin had orange peel texture. So I researched. My dog was covered in black fungus along w/ fungal leisons – which is Malassezia, turned invasive.
This particular yeast/fungus doesn’t eat sugar like Candida, it eats FAT. Medium chain triglycerides to be specific. Olive oil and coconut oil – nom nom. So folks treating these mysterious skin conditions were making it worse. The yeast shoots out hyphae that roots into the skin and follicle, and then stimulates the oil gland. It can turn on it’s own food source – oil – hence the skin becomes more oily. It can turn red. Psoriasis, eczema, Pityriasis versicolor, seborrheic dermatitis, dandruff – it’s a huge contributor if not the cause of a whole slew of skin conditions dermatologists in all their wisdom treat with liver-killing medications, Retin-A (which does help prevent it from getting totally disgusting), etc. One thing they are correct about is using a petrolateum based moisturizer. 1) the molecules are too big to clog a pore, 2) it hydrates the skin from within by creating an oil barrier, and 3) it’s carbon chains are too long for Malassezia to eat. So it’s not food. The only way researchers could get malassezia to turn hyphal in a petrie dish (grow into a blob of mold) is to add a drop of olive oil!
Now that this fungus is rooting into your skin, it’s creating even more inflammation. That causes the itching and redness, and even more oil. My hair would literally blow out with oil around 9pm at night to where it looked like my roots were dripping wet. Gross. And still the derms wouldn’t believe me. Amazing. I have microscope photos of tons and tons of hyphae on my face, scalp, chest…. And when they get active – I realize my immune system tanked around 9pm, inflammation rose, and it activated the yeast – my USB microscope had a video feature so I held it in place for 20 minutes, fascinated as a hyphae would grow out of a pore, spiral around a hair shaft, and start uprooting globs of crap from the follicle. This is “dandruff.” The follicle is overstimulated from the active and reproducing fungus, and the grease lets the white clumps easily slide along the hair shaft, away from the pore. Keratin + sebum + oil + malassezia = it’s quite disgusting on microscope, live, on your own body! Morbidly fascinating.
When it reproduces, it creates spores. But to protect them, it also sprays down a biofilm of sticky organic matter. So when we (the Roscea (sp) forums have done a ton of self-experimentation, smart folks out there along with the ones who try……) So when we apply an anti-fungal product, it slathers over the layer of biofilm. Yeast and baby spores are protected. (this is the exact cause of antibiotic resistant bacteria as well – boifilm). So the oil can’t clear up over night, it takes a long time to break that biofilm.
Interesting the author referenced a “dandruff shampoo” article in attempt to explain oil production. So this is the missing key. OTC shampoos for dandruff (the most evident malassezia infection, so I’m using it as example) have a bunch of crap in it like sodium laural sulfate, the ingredients that *look* like “coconut” but are really toxins – the things to get a nice lather. Shampoo that doesn’t lather is so much healthier. But they use Zinc (some form of it) in one version, and derms recommend those shampoos because the only other “commercial” P&G sort of shampoo for dandruff has selenium sulfide. The derms recommend *against* using that one because the selenium sulfide builds up in your body as a toxin. Surprise surprise. Yet when those were my 2 options in the early days, that was the product that actually stopped the itching and the nightly grease blow-outs.
Here’s why. Sulphur. They changed naturally occuring sulphur through chemistry, binding it to something or other. But the yellow stuff that smells like rotten eggs – that’s a bacteria, fungal, biofilm eating machine. And it’s not harsh. MSM I’m looking into, and it looks promising as well. Methylated sulphur. Perhaps like methylated B-12? Dunno. Tea tree oil – i’ve only had so-so results. Neem oil, not so much.
I find treatments for my dog’s skin by reading horse blogs. They get horrible fungal infections in their hoofs, up their chests, along their backs – identical to my dog. It turned out my condo was filled with mold from a leaky roof. Long term, but between the drywall and in the ducts. The dog was on the ground most, and in contact most. A product for horses is something like 95% yellow gritty nasty smelly sulphur, mineral oil (long carbon chains, too long to eat), and pine oil – not sure why pine.. Maybe for smell? I loaded the pup’s feet and nails up with that, covered them with socks held on with velcro on top of the joints, and let him mope for 2 days. When I took it off, HUGE IMPROVEMENT. Sulphur is a miracle substance as far as I’m concerned – for skin stuff. But it DOES smell like @$$.
Jason’s is a brand that has a sulphur shampoo with mint and other stuff – the real deal. It takes a while to work since I rinse it off after 5 minutes, but my conditioner was enough to mostly mask the sulphur smell. Now I’ve found sulphur creams (10%) that I’ll use on my face overnight. I know I start loosing the battle because my face starts peeling while being oily. I’ve also been on an anti-fungal med for 2 years – Diflucan, daily – and my still-unknown immune condition is so high the malassezia (or candida, or tinea – whatever the athlete’s foot yeast/fungus is) lessen, but are still winning. A petrolateum based hair product for african americans that has 2% sulphur has also been helpful for both the dog’s and my feet.
Sorry to go off – there is so much *almost right* and *way off base* information out there, and this topic is near and dear to my heart I sometimes can’t restrain and dump the info. Sprinkling it here and there. The medical community maybe 60 years ago had alarming high death rates for women and/or newborns in the hospitals. One doctor, against all the “evidence based research” they had at the time, forced his hospital to wash their hands before performing births. The death rate dropped from maybe 15% down to 1-2%. He wrote it up in all the journals, his reputation took a beating, the usual politics and investigations into negligence I’m sure occurred. But he stood firm. It took the medical profession as a whole about 50 years before doctors began routinely washing their hands before delivering babies and “miraculously” the death rates went down across the country. (likely attributed to anti-biotics lol!!!!!) So it will be a long time to turn the Titanic of Modern Medicine and many will suffer as the politics and egos play out. It saddens me, maybe because I’m stuck in that Lyme “hysteria” and quite sick, so I see it. To quote one Lyme Dr. who’s name escapes me, what shows up in the exam rooms (US! People needing help!) doesn’t reach the Ivory Towers of academic medicine.
And to prove how sad this is – my Immune doc showed me 2 articles when I said no doctors would believe me regarding all these symptoms I have. The first was “peer reviewed, published in a scholarly journal” article on how a statistically significant number of patients with multiple ‘mysterious’ symptoms that doctors don’t know how to test for are falsely diagnosed as “depressed” and actually wind up with depression (hopelessness at not being believed yet again, told they’re crazy – I have “psychosis” in one of my dermatologist reports lol!!!!!).
The second article – same sort of “peer reviewed, published in a scholarly journal” article was about how a statistically significant larger number of patients with multiple ‘mysterious’ symptoms commit suicide than normal patients with depression.
It doesn’t exist until it’s published, apparently! I can still only shake my head in amazement….
Fascinating! I would love to read updates on your progress.
Great post. Wash face on time to time is the best way to remove oil from skin. washing face in summer is very important to every one. I liked your post. thank you so much for sharing this lovely article.
First, I’d like to start with a precaution: this is a critique meant to help you in your endeavors, not to be a mean, harsh, nasty person. I do the tough love thing, so with that said…
The below paragraph highly contradicts itself, which leads me to suspect either misinformation, not enough conducted research, or poor communication/writing skills.
Therefore, I’m hoping you can clarify what you are trying to communicate. For ease of explanation (on my part), I have quoted your writing, then added my reasoning as to why I believe your statement contradicts something else you’ve written in that paragraph. Side note: All quotes are from the second paragraph under “Skin can’t sense how much oil is on it”.
“The problem with applying this is that there isn’t any way for the skin to detect how much oil it has on it. Sebum is produced to a certain level on the skin, and is stopped by the physical phenomenon of surface tension, so you’ll end up with around the same total amount of oil on the skin, whether it’s natural sebum or skincare oil or a combination.”
This contradicts itself. You write that “there isn’t any way for the skin to detect how much oil it has on it,” yet you note that sebum production is stopped by “surface tension”. By my logic, if the skin’s “surface tension” prohibits further sebum production, then isn’t it logical to conclude that “surface tension” is a detection mechanism in itself?
And on that note, the term “surface tension” makes no sense. By definition for the purpose of something tangible, not intangible, tension is the act of stretching or being stretched. How does stretching the skin (whether with your hands, a smile, etc.) prohibit sebum production? Sebum production is genetic & hormonal, which you get into with the next quote.
“The amount of sebum your skin ends up with depends on genetics and hormones – not on how much oil you put on the skin.” But ah…this in contradiction to “Sebum is produced to a certain level on the skin” and the whole “surface tension” thing.
And another note: with sebum being produced up to a certain level on the skin, and you say the skin has no way to detect how much sebum is on its surface, then why are you noting that sebum production “is stopped by the physical phenomenon of surface tension”? So this so-called “surface tension” talks to the hormones? “No. Wait. Stop. I’ve had enough.”
I’m not buying what your selling. Sebum production is ongoing. It may lessen due to hormonal changes as we age, but it doesn’t temporarily stop at say…3:00 p.m. and then pick back up at around 3:00 a.m. just in time for you to have that lovely morning shine.
In conclusion, I hope that for your future articles, you either conduct better or more extensive research (rather than referencing/relying on just one source), consider the words you use and how you structure your sentences and paragraphs, and/or have someone in the field proofread your work (like a university professor of dermatology or your local dermatologist). I’m an author; I know how vital proofreading, a second pair of eyes on your work, and technical skills can be.
Many people read the information you provide (I’m certainly not saying the contradictions and/or misinformation is intentional). Those people might not catch the mistakes in your article, and that’s a shame because ultimately, you are responsible for their being ill-informed. Being a blogger/writer is a responsibility, not a hobby.
Again, I say these thing to help you in your future endeavors…not hurt or discourage (though my harsh delivery, I’m sure, will leave a bad taste in your mouth for a while. Harshness stings at first. I know; as a writer, I’ve had my fair share of harsh criticism that has only benefited me.) I DO hope my comments help in a positive way somewhere down the line.
I did a PhD, so I’m very used to and open to criticism 🙂
“The term “surface tension” makes no sense” – Surface tension is a very common, basic scientific concept, so a lot of people would disagree! It’s a property of the oil, not the skin. An example would be a rope dipping into a pool of water – the water climbs up to a certain height on the rope based on water’s surface tension, but the rope doesn’t have a way to tell the stream entering the pond to stop adding water to the pool. Unfortunately bringing a dermatologist into this wouldn’t help, since they’d agree with the fact that oil rebound isn’t validated, and would probably be worse at explaining it…
I may be wrong, but from how passionate you seem to be in your comment, I suspect you’re a firm believer in the oil-rebound theory? It may be worth considering if you’re a victim of the backfire effect.
This response was a masterclass in grace, Michelle. <3
Hi im 18 i have oily skin and i have seborrheic dermatitis on face I never wash my face with soap or any cleanser because my face gets flaky after i wash it with cleanser, but when i only wash it with water my face still get flaky but no too much. Is it okay if i just wash my face with water? I need really help 🙁
You might want to try out a gentler cleanser first – check out this post on choosing a gentle cleanser for more info!
Great post, thank you! I still got one question which I think wasnt covered by you: Are mattifying products stripping of hydration/moisture of your skin? Or are they “safe” to use by which I mean that they don’t interrupt with the natural functioning of the skin?
Some will, some won’t… there isn’t a hard-and-fast rule!
Interesting! Are there any benefits from face oils? Do they just sit on the skin?
Some do and some don’t – I’m working on a video on this 🙂
Hey I am experiencing very high hairfall from past one year I got dandruff currently I am using a zinc 8x shampoo for it.but nothing seems to be working for me
Hey Michelle, Thank you for sharing this guide about oily scalp. I am currently facing oily scalp problems. But the tips and remedies that you mentioned it are quite helpful to me. Thanks for sharing keep updating.
Thank you for this post! Someone tried to sell me moisturizer once on the pretense that my skin was oily solely because I didn’t moisturize. She was adamant that skin gets oily because its dehydrated. Well, maybe in some cases. But, I’ve had oily skin for my whole life and it’s perfectly hydrated, so I wasn’t buying. You hit the nail on the head: ‘if your skin is healthy and still oily, nothing you slap on your skin can change that’
This is false. There IS a regulator to check how much oil is produced, that is confirmed in the sebaceous gland research from 1957. https://www.sciencedirect.com/science/article/pii/S0022202X15490633
That paper agrees with everything I described here – that there’s no feedback mechanism, and that sebum levels are controlled by capillary action and surface tension.
And how fluid surface tension is not a feedback loop? You’re using something similar every day when you flush the toilet.
This is in direct contradiction to your proposal that removing oil from the skin doesn’t cause more oil production. Of course it does, because you broke the surface tension, which is the only stopping mechanism. The key here is to induce a production of a more viscous oil, by lowering triglycerides and increasing unsaturated fatty acid content, primarily linoleic acid.
Surface tension isn’t a physiological feedback loop, which is why the paper and this post don’t describe it this way – there’s no long-term effect, and adding oil can go either way (you can end up with more oil if you use an oil with a lower surface tension).
Removing oil from your skin will only cause your sebum to come out to the same level – the endpoint is the same, so there isn’t increased oil.
I think you’re also confusing oil production with distribution of existing oil.
Also, lowering triglycerides and increasing unsaturated fatty acids will lead to a less viscous oil (see e.g. https://doi.org/10.1007/s11746-997-0048-6, https://doi.org/10.1007/s11746-000-0197-z)
I’m not confusing anything. The trouble is that by removing oil from the face, the body is forced to spend more resources to produce it again. It is, therefore, of lesser quality, as it has to substitute essential linoleic acid with oleic acid, which tends to oxidize. Nobody is talking about the exact “overproduction”, as there is no such thing, like hair and nails don’t grow “stronger” as you cut them.
As I am sure you saw already, triglycerides, sapienic acid, squalene and esters are much higher and unsaturated essential fatty acids, predominantly linoleic is much lower in sebum of acne sufferers. This shows exactly what is being used to produce sebum in larger quantities to compensate for the lack of uefas.
Surface tension is perfectly valid physiological feedback loop, I don’t really care why it is disregarded by you or anyone else for that matter. My bad, I meant less viscous, so it can withstand shear stresses better.
>The trouble is that by removing oil from the face, the body is forced to spend more resources to produce it again.
Sebum, especially if you confine it to face sebum, is an incredibly small and insignificant part of where the body’s EFA resources go.
>It is, therefore, of lesser quality, as it has to substitute essential linoleic acid with oleic acid, which tends to oxidize.
Linoleic acid is far more prone to oxidation than oleic acid (see e.g. https://link.springer.com/article/10.1007/BF02643258)
>Nobody is talking about the exact “overproduction”
Yes they are – Google the phrases at the start of the post. It’s obvious that they’re claiming a negative physiological feedback loop exists, where removing oil is “signalling” the skin to produce less oil.
>As I am sure you saw already, triglycerides, sapienic acid, squalene and esters are much higher and unsaturated essential fatty acids, predominantly linoleic is much lower in sebum of acne sufferers. This shows exactly what is being used to produce sebum in larger quantities to compensate for the lack of uefas.
Not necessarily. Simply lowering linoleic acid would also result in higher percentages of those, without necessarily any sort of “overcompensation” effect. There also isn’t any good evidence that topical linoleic acid or linoleic acid-containing triglycerides changes the composition of sebum.
>Surface tension is perfectly valid physiological feedback loop, I don’t really care why it is disregarded by you or anyone else for that matter.
If you examine any other physiological feedback loops, it should be clear why it isn’t considered a “perfectly valid” feedback loop – here’s a simple explainer: https://courses.lumenlearning.com/ap1/chapter/feedback-loops/ It’s like claiming that when you take dirt away from the bottom of a pile and gravity makes more come down, that’s a feedback loop.
>My bad, I meant less viscous, so it can withstand shear stresses better.
Lower viscosity leads to more oil on the skin, since it can flow out more easily. Higher surface tension would lead oil to remain in pores since capillary action is lower. This is borne out in temperature/sebum studies – so according to the logic you’ve presented here, higher linoleic acid content in sebum would make skin oilier.
The current opinion on how linoleic acid is involved in acne pathogenesis is because it’s related to inflammatory signalling pathways, not sebum/surface tension, since as you demonstrated, it would predict the opposite effect. Sebum quantity also doesn’t seem to be as big an issue as sebum composition itself. See e.g. this paper: https://doi.org/10.1111/jdv.12298
>>Sebum, especially if you confine it to face sebum, is an incredibly small and insignificant part of where the body’s EFA resources go.<>Linoleic acid is far more prone to oxidation than oleic acid<>Not necessarily. Simply lowering linoleic acid would also result in higher percentages of those<>If you examine any other physiological feedback loops, it should be clear why it isn’t considered a “perfectly valid” feedback loop – here’s a simple explainer: https://courses.lumenlearning.com/ap1/chapter/feedback-loops/<>Lower viscosity leads to more oil on the skin, since it can flow out more easily. <>The current opinion on how linoleic acid is involved in acne pathogenesis is because it’s related to inflammatory signalling pathways, not sebum/surface tension.<<
The low levels of linoleic acid lead to impairment of the epidermal barrier function, which leads to more inflammatory substances get through the comedonal wall. How it's related to "inflammatory signalling pathways" exactly?