Skin Chemistry: The Biggest Myth in Fragrance?

[00:00:02]Hi, welcome back to the fragrance standard where I bring you news and reviews on fragrance so you guys don't have to waste your money. I hope you're all well and today I'm going to do some more investigative journalism in the fragrance space and I'm going to investigate the skin. We keep hearing from many many sources that fragrances are smelling different on different people's skin. And the commonly recited reason for that is because our skin microbiome is actually affecting the fragrances at a molecular level. So, we've all seen reviews of fragrances like these where they're very, very polarizing that people have said, you know, on my skin, this smelt like pickles, pickled gerkins, and on my friend's skin, it smelt absolutely amazing.

[00:00:54]And I think there are some reasons that that happens, but I don't think it's what is perpetuated among most of the industry websites on the forums. That uh skin pH stuff that we keep hearing about is the one that's touted most readily.

[00:01:13]Is there any truth to that? Let's find out. The standard position is that fragrance molecules are affected once they've left the bottle and landed on your skin by a variety of biological factors, pH level, sebum production, microbiome composition, body temperature, and hormone profile. And probably the most repeated one of those is the pH. Now, skin pH sits roughly between 4.5 and 6.5, creating an acidic environment. The standard claim is that slightly acidic skin from 4.5 to 5.5 enhances woody and musky notes while dulling bright citrus and more alkaline skin at 6 to 6.5 makes floral and fresh notes more prominent. And this advice is perpetuated so often that it's just taken as fact. No one really questions that. So let's see what the science says. The key study is Behan Etal which was in the international journal of cosmetic science 1996. This study was based on headsp space analysis measuring fragrance concentration in the air above skin and solvent swabbing measuring what's left on the skin to monitor fragrance in actual use. They split the question in two physical interactions.

[00:02:35]They compared perfume behavior on skin versus on a relatively inert surface, a vitrius tile. It genuinely differs. So, the physical effect is real and measurable. Skin is not a neutral surface.

[00:02:50]And here's the finding that kind of guts the myth. They examined the potential for skin mediated chemical transformation across a wide range and found little of it. the honest quote of their conclusion, "Some evidence has been found for changes in perfume ingredients in the underarm, probably arising from microbially catalyzed reactions." So, they discovered that there were changes in the skin, but this was pretty much restricted to the area underneath the arms. The rest of the skin, they didn't see massive changes in the fragrance molecules at all or in the profile. But we have a newer study for those of you that might complain that that is a little old. Excuse my pronunciation. This is Hajistau at International Journal of Cosmetic Science 2025 exploring the impact of fragrance molecular and skin properties on the evaporation profile of fragrances. And they built an invivo system using SPME, solidphase micro extraction and gas chromatography to track evaporation from real skin. The framing is telling. The modern research question is evaporation, not chemical transformation. That's where the science actually is. And so if we break this down, pH has a smaller direct effect on fragrance smell than hydration and oil levels. Its role is limited to influencing enzyme activity that may subtly alter compounds during dry down. The acid mantle matters, but it is not the dominant factor. It's the opening act, not the headliner. So, it does have a a small interaction, but it's nowhere near enough that you would notice a substantial difference.

[00:04:35]Certainly, when you get influencers that are saying, "This smells absolutely disgusting on my skin, but on my friend's skin, he must have a better pH.

[00:04:43]It smells absolutely fantastic. It's a compliment machine on his. You know, that's just not accurate at all. Most people sit between 4.5 and 5.5 on the pH and that's a pretty narrow band. And although aldahhides, ers and tarpen are sensitive to acidbased conditions in principle, in practice, healthy people cluster tightly in pH level. and Behan found the transformation just isn't happening other than under the armpit as we've already discussed. And the thing that really kills the pH argument is your own pH isn't even stable. It's shifted by soap, hard water, sweat, skin care activities, glycolic acid, salicylic acid, and stress. The skin you sprayed at 8:00 a.m. is not the same as the skin you spray at 6:00 p.m. So, if pH were the master variable, your signature scent would smell different every single day you wore it from one part of the day to another. You could spray someone in the morning and smell great. You could spray someone in the evening and it would smell absolutely disgusting. And I've never ever heard anyone talking about that. You know, these influences that have a favorite scent that they wear all the time. I've never heard any of them say, "Oh my god, I can't wear it in the evenings. It smells disgusting." So, I think we can pretty much rule out the PH argument.

[00:06:08]The science debunks it. And if we play that last part through ourselves, we can we can probably debunk it just using common sense. So, what is actually happening? So, there are mechanisms that have an effect on the smell on skin.

[00:06:24]Sebum as a physical fixative. Sebum's secondary job from a fragrance perspective is to anchor fragrance molecules to the skin surface. It acts as a natural fixative, slowing evaporation of aromatic compounds and keeping them close to the skin longer.

[00:06:41]More sebum equals slower evaporation.

[00:06:44]Better longevity and more sustained projection. Oily skin holds fragrance longer and scents are richer and more sustained. Dry skin lacks the sebum to anchor the molecules. So compounds evaporate faster and base notes may not fully develop. That's the key because it means dry skin people are genuinely experience a truncated version of the fragrance. Unfortunately, I'm one of those dry skin people. And there's going to be a second video that I'm going to release on this subject, which is how we can combat some of these issues and actually get a better deal from our fragrances if you are unlucky enough to have dry skin. My wife, however, has not oily skin, but she has a kind of Mediterranean skin, which is certainly not dry. I commonly get dry patches on my skin. She never gets anything like that at all. She's got very very soft and and pleasant skin and she really has a great time with fragrances. You know, they last a long time on her. She doesn't understand people talking about um fragrances kind of dying off quickly.

[00:07:51]She never has that issue. So, we can probably thank her skin for that and that's down to her sebum production.

[00:07:59]Oily skin can also amplify base notes strongly. heavy oriental or musky fragrances applied generously on oily skin can become overwhelming. So whilst having this increased sebum production and oily skin can be beneficial, you also have to be careful. You can kind of go over a tipping point which may be where people say, "I can't stand this fragrance on me. You know, it's too cloying. I really don't enjoy it. It goes right up my nose." That could be because they are blessed with decent skin that's producing a decent amount of sebum and that becomes a problem of overspraying. It's as simple as that.

[00:08:36]That if they sprayed less of the fragrance, they might only need a couple of sprays on their skin and they would be good to go for the whole day because they're going to get that enhanced projection, enhanced seage, enhanced longevity, but they might be overdoing it. So, there's also something to be said for these videos where they're like, "How many sprays should everyone do? You know, you should do six sprays with this perfume and with this one it should be eight. And if you're running Outlands, then it only should be two."

[00:09:06]There is no fixed answer to that. That is purely down to the individual. If you're someone who has incredibly dry skin, you would need to spray more. If you're someone who has incredibly oily skin, you would need to spray less. in simple terms. Now, something that should be basically common sense in this area and isn't that generally spoken about, everyone gets obsessed about this pH level, which we pretty much discounted, is the skin microbiome, which creates subtle background notes that blend with perfume molecules. So, the popular concept is the perfume molecules are being changed by the skin, which the science does not support. But what we do know is that the molecules mix with the molecules already on our skin which is personal to us creating in essence a different fragrance altogether. You're smelling the fragrance plus the person.

[00:10:00]And I'm not just talking about the obvious. You know, if someone's got really bad body odor, of course things aren't going to smell great on them. But if we take that out of the equation and we imagine everyone's had a wash that morning or that evening and then we smell them, they still have a personalized smell. Warmer skin intensifies base notes like musk and vanilla, accelerating evaporation and projection. Cooler skin slows the entire development cycle. And rougher skin increases the surface area available for evaporation, accelerating top note release and reducing longevity. So, if you're someone who has good sebum production, you've got very young skin with no wrinkles, no roughness, you've taken care of it, and your body runs pretty cool, you're in a great situation that you're going to get the most from that fragrance. And if you're someone like me who's a bit older, I've got pretty rough and ready skin from years of doing, you know, manual stuff outside and uh not taking care of my skin properly. And I also run pretty hot as well. You know, if I go and do some physical activity, I heat up really quickly. Then you're on the unlucky side of things. You know, that that fragrance is going to be evaporating really quickly on you.

[00:11:18]You're not going to get as much longevity out of it. Um, you will get an enhanced level of projection to start with. You know, if you go to the gym wearing a fragrance, it really projects.

[00:11:29]That's why people complain about fragrances at the gym because you heat your body up. You're enhancing that projection, but that's giving you less longevity. Heavy base notes are the most robust. Woody, amber, oud, and musk bass notes perform consistently across most skin types. They're heavy molecules which evaporate slowly and hold regardless of pH variation. And they also bear up to being kept in a bottle for a long time as well. You know, we've discussed that in the previous videos about masseration. One thing science does really support is that we're all massively different in terms of our ability to smell fragrance. So specific anosmia is the inability to perceive a specific odor while alactory perception is otherwise intact. You can smell roses, citrus, vanilla, everything except one molecule. The proposed analogy from genetic literature is like color blindness in vision. Humans can carry roughly 400 types of alactory receptor, each tuned to specific molecular shapes. If the gene for a given receptor is faulty or missing, the brain simply never receives a signal.

[00:12:42]And the numbers are actually quite stunning on this. So iso superree, 20 to 25% of people cannot smell it at all.

[00:12:51]And it's everywhere. Used in compositions at concentrations from 25 to over 70% with global production around 3,000 tons per year. Entirely synthetic first created in 1973.

[00:13:05]And many many fragrances have that in, but maybe a quarter of us can't even sense that at all. Macrocyclic mus up to 40% of people can't detect certain ones.

[00:13:18]Galaxalide. The receptor has been identified O4D6 with few exceptions. Participants homogeneous for the O4D6 variant are unable to smell galaxalite. Musk penta decolactone about 70% of Caucasians couldn't smell it. Uh that was in a study whistle bi and amore 1973. And this is an inherited autotosomal recessive trait. This is a really interesting one. Body odor itself. 3M2H described as the impact odor of underarm body odor. Specific anosmia runs at about 21 to 25% of the population. So a quarter of people can't smell the primary component of BO. That means that when you've got that person in the office that you're thinking, "How did they even come to work today? They absolutely stink." They may not even know that they stink. They simply can't smell it. Which is both a blessing and a curse, right? Because they don't get to smell anyone else's BO, but at the same time, they might be walking around absolutely humming, making everyone feel sick, and they think that they smell just fine, which is crazy to me. You know, this is a a really interesting part of what I found out here. And the universal stat, one study found 45% of 153 healthy subjects were a nosmic to at least one of six tested odorants. And the estimated probability of being a nosmic to at least one out of 100 is 98.3%.

[00:15:00]Effectively, we all have blind spots.

[00:15:02]There are very few people, if any, that can smell every single odor known to man. The people that are blessed with the alactory system like that probably are working in perfumery. The upshot of all this is when two people smell the same wrist, they might have wildly differing experiences and thus wildly different opinions, which is why the influencers may have such wildly different opinions. You know, you'll have an influencer that has a favorite scent, a least favorite scent. That will be massively different to someone else's. So, the good news is that that might not be down to things like monetary gain, sponsorship, or that kind of thing. It really is down to how an individual perceives fragrance. The bad news is that that means you really have to go out and smell things for yourself.

[00:15:52]It's fine to watch these videos as a enjoyment, a bit of fun. You might find an influencer that you share similar alactory kind of senses with and everything that he's said is good, you also enjoy. I've found a couple of those myself. I kind of know that when they say that something's good and I go and smell it, I tend to enjoy it as well.

[00:16:15]And the things that they don't enjoy, I don't either. So you might sort of find that you have to team up with an influencer that really suits your old factory system, which is kind of a weird concept. I know there are influencers that I can't believe are suggesting some things are good. You know, this may even tie in with some of my clone videos that maybe those clone factories are using some of these chemicals which have a very high percentage of anosmia. Now, the only part that makes me slightly question this is I've heard a lot of influencers talk about they would spray something on themselves and it just wasn't any good at all. They hated it. It didn't smell good and then they sprayed it on someone else or they gave someone else that scent and it smelt great on them. The science does not support that. Apart from the blend of someone else's personal body odor, which I think you would probably notice, you know, if you had a wildly different body odor to someone else, I think that would be fairly apparent. It's usually um talking about pH levels. You know, they say, "I gave it to my friend. He must have a better skin pH than me." And there, like we've seen, there's no evidence for that at all. I do wonder if some of that is an easy out for influencers because most influencers are on some kind of paid situation from the perfume manufacturers of one kind or another. I'm not knocking that. We're all here to do some business and make some money. I try to on the side of being truthful because I think the the money to be made for me on YouTube is presenting a truthful, honest and believable channel to the viewers and kind of upholding the viewers end of things whereas other people might see themselves as working for the manufacturer and more of a a sales role and that's fine as well. And I don't mind selling stuff. You know, I promote some of the things that I like. I I promote some of the fragrances I really love on here. I don't get paid by the fragrance companies to do that. But if I really like something and they offered me some money to promote it and I liked it, I wouldn't have an issue with that.

[00:18:30]I'm not against that. But I think if you just get money from a manufacturer to promote every single thing they do, there will be points where to keep it believable, you can't simply say you love everything. So, you have to have an out. You know, you can't also say this one smells like crap because then you're slagging off the brand and you're damaging the brand. So, an easy out, I think, would be to say, "Oh, my skin pH isn't good with this one. It doesn't smell great on me. I won't personally be wearing it." But, I did give it to my friend, and it smells amazing on him.

[00:19:07]So, it's a way of them kind of wiggling out or saying maybe some uncomfortable truths that they personally didn't like something. They would never wear it.

[00:19:15]They felt it was not a great perfume or fragrance, but they're going to back it up with, "Yeah, but it's still good.

[00:19:22]It's just not good for me." I think there's probably a lot of that that goes on. So, what are the conclusions of this? What are the practical things that we've learned? Paper strips cannot replicate the enzyatic and bacterial activity present on skin. So there is some effect. We've agreed a fragrance that smells appealing on a blott may develop unexpected notes on your body and it may also improve on your body.

[00:19:45]You know, I've said this many, many times, especially when discussing oud.

[00:19:50]Spray it on your skin. I always have a better time, especially oud on skin, than I do just spraying on a blott. I really only do those blott strips um because there's only so much skin that I've got for one video. So, if I'm doing a lot of different fragrances, I obviously have to. Also, it's something that's now kind of expected. People like to see it on the video. And it does give you a ballpark idea, you know, of what kind of fragrance it is. It won't be structurally changing unless you're spraying it under your arms, but certainly your own body odor may affect it and you may have a different experience and your level of oil on your skin is going to affect it as to whether it performs well or not. Always sample with your own nose. As I've said already, given the Anosmia numbers, which are frankly quite shocking to me, other people's reviews are describing a fragrance you may literally not be able to perceive. And I've had this a lot.

[00:20:47]I'm sure you guys have as well. So, just take the reviews as something of entertainment. They're just like news stories bringing you out what's new in the industry. You need to get into the store yourself or order some small samples yourself and actually get your own nose on it and see what you think about it. And just be skeptical of anyone with a free bottle who's really really confident in the old biology stuff. Oh, it's just my skin pH.

[00:21:13]Whenever there's free stuff and whenever there's money, especially lots of money, there is some disingenuous stuff going on. So, just be careful about that. Use these videos as a point to push you into having a journey of discovery yourself.

[00:21:29]Don't use them as a kind of catalog to buy from. You know, if you're watching videos and then you're blindering fragrances, you're going to end up pretty disappointed at some point. If you're watching videos because they're entertaining, because they're fun, and that launches you into a a journey of finding some of your own fragrances in the shop, exploring what was discussed in the video, getting your nose on those, finding that you really like it, then fantastic. The video has done its job. There is a space for fragrance influences, but I think you need to be careful how you utilize their information. if they're direct selling to you and you're buying off the back of that. I see that a lot with the clones because they're cheaper on the price point and you get these guys every week saying, "Get this. It's the best thing ever. It's the best thing ever. It's the best ever every single week." And you guys are just thinking, "Well, it's only 30 or 40 bucks. You know, I'll just buy that." That's the the kind of direct sales thing that I have an issue with.

[00:22:30]You should be going out seeing if you actually like those things. And you know, once you've bought 10 of those cheap clones on the back of some influencer guy saying they're all the best thing in the world, you basically spent 400 bucks and you could have gone out on your own discovery journey, smelt some amazing niche stuff, and you could have ended up with a bottle of something really, really good, high quality ingredients that you absolutely have fallen in love with. I hope you guys enjoyed that. Hang around for part two.

[00:23:02]that'll be out in the next couple of days where I'm going to be talking about the practical steps we can take to improve things like our skin so we get a better experience with fragrances that that annoying person like my wife who her fragrances last all day on her beautiful soft oily skin and me having to reapply. There are steps I can take to improve my situation and I'll go through those next time. There's some myths in that as well which we'll cover and I'll try and debunk for you. Thanks a lot for watching. Take care.