The comedogenic rating scale was born in 1979 on the ear of an albino male rabbit. It has since grown into a gold standard of qualifying ingredients for acne potential. A quick Google search of comedogenic scales pulls up thousands of results, often with contradictory ratings. So how can you trust the evidence? In this episode of ASCP Esty Talk: 2 Es in a Podcast, licensed estheticians Emily Morgan and Ella Cressman answer all the burning questions you never knew you had about (supposed) comedogenicity: What is it? How does it work? And how can we better use this scale as licensed professionals and consumers?
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About Ella Cressman:
Ella Cressman is a licensed esthetician, certified organic formulator, business owner, and absolute ingredient junkie! As an educator, she enjoys empowering other estheticians and industry professionals to understand skin care from an ingredient standpoint rather than a product-specific view.
She has spent many hours researching ingredients, understanding how and where they are sourced, as well as phytochemistry, histological access, and complementary compounds for intentional skin benefits. In addition to running a skin care practice, Cressman founded a comprehensive consulting group, the HHP Collective, and has consulted for several skin care lines, including several successful CBD brands.
About Emily Morgan
Emily is a licensed esthetician in Massachusetts and Colorado, having graduated with a 4.0 GPA with additional certifications in microdermabrasion, spray tanning, and eyelash extensions (her specialty). She currently works as the Membership Program Manager at Associated Skin Care Professionals, where she works to provide helpful resources and tools for estheticians to help them grow and thrive in their esthetic careers.
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0:00:37.8 EC: You are listening to ASCP Esty Talk, where we share insider tips, industry resources and education for estheticians at every stage of the journey. Let's talk, 'cause ASCP knows it's all about you.
0:00:54.3 EC: Hello and welcome to ASCP Esty Talk, the ingredient decked out series. Here we explore the fascinating world of ingredients and how they work within the skin. I'm Ella Cressman, licensed esthetician, certified organic skin care formulator, owner of the HHP Collective and a total and complete ingredient junky. Today, I'm happy to again be joined by Emily Morgan, who is also a licensed esthetician and membership program manager for Associated Skin Care professionals, as well as a fellow host of ASCP Esty Talk. Hey Emily.
0:01:29.0 Emily Morgan: Oh hey.
0:01:30.7 EC: So this is not our first podcast together, right? And we have so much fun doing these.
0:01:34.8 EM: Yes, I love it. It's like, you know, we're just sitting here having coffee, gossiping a little bit before our podcast episodes, and then we get into it, it's so fun.
0:01:43.1 EC: Having Esty Talk like two Es in a podcast.
0:01:47.2 EM: And so we're hoping to do a lot more of these and that's what we're gonna call them, two Es in a podcast.
0:01:54.3 EC: So today, let's kicky about something super fun, you know, many of my rants, as you know me now, very well. I'll start with a... Usually a social media maranding. [chuckle] I was perusing through and something happened, probably about a month and a half ago that was irritating, to say the least. It was a post about a product and it was just the ingredient deck that they took a picture of and they posted online, and they said, "Is this product good for my clients, I'm using it for this specific function." And people started to chime in that the constitution of this product was, "This ingredient was comedogenic, that ingredient was comedogenic, and that's a horrible product, that's comedogenic."
0:02:37.2 EC: And the truth was one of the things that they said was Argan oil. "The Argan Oil is comedogenic," and a quick Google search will lead you to see that actually Argon oil has a comedogenicity scale rating of zero, so not in fact. And it led me to think... And watching this post and some behaviors that ensued led me to realize that what the heck, WTF, what's the function of the comedogenicity scale, what the hell does it mean? So as an esthetician learning about this in school, but also as a formulator, understanding the difference of different oils, for example, and we'll get into that in a minute. I thought, "What the heck is this?"
0:03:17.1 EC: So today we're gonna talk about comedogenic rating scale for ingredients. And I think before we get into the scale and everything, what that means, I think it would be helpful to kinda do a quick little recap of what comedones are what, what is comedogenic? What does that mean? And honestly, if I mis-pronounce anything, please just know that the English language makes absolutely no sense to me, it's comedone and then comedogenic and I just... I don't understand, so if I slip up, don't blame me, blame the English language.
0:03:50.2 EM: I agree.
0:03:55.6 EC: Yeah, makes no sense. So let's do like just a quick little review according to our dear friend, Milady, Milady textbook. So a comedo as we know is a blackhead, a mass of hardened sebum and skin ____ within a hair follicle. So when a follicle is filled with the excess of oil a blackhead forms and it's dark because it's exposed to oxygen and it oxidizes; while a closed comedone that is... They're usually plural because they're rarely just by themselves, unfortunately, they bring all their friends, but those are your whiteheads, those are the things that your clients are itching to pop, maybe sometimes you're itching to pop, we get it.
0:04:37.8 EM: The things we dreams about at night.
0:04:42.5 EC: Right, right. We're watching videos of it constantly, so satisfying. And then we have some other terms, comedogenic, so that is a tendency to clog follicles and cause build-up of dead skin cells resulting in comedones. So, that being said, comedogenicity is the tendency of a topical substance, so like your products, your oils, or serums and all that to cause or worsen a build-up in the follicle, which leads to the development of a comedo. So knowing what all those little guys are, there has been a scale that was created based on what products or what skin care ingredients and things were the most clogging or the least clogging, which Ella, why don't you tell us a little bit more about this scale I know you love so much.
0:05:37.0 EM: Oh yeah, eye-roll, big fan. Huge fan of this, I'm not. And I'm not because it's been taken as word to be this golden rule, right? It's this, "Maybe, maybe not scale," that has been used as gold as aesthetic professionals, and it makes sense because we deal within our scope of practice with topical application, especially concerning acne. So we have clients who come to us and they're like, "Oh, we need help." Whether it's... At all ages, let me tell you, but it would be so easy if it was just an ingredient that was the culprit rather so many factors. Yet, we look to an ingredient deck just to point fingers, literally. So let's talk about the comedogenicity rating scale. This scale was developed in 1979 by a very well-known and respected dermatologist named Albert Kligman.
0:06:36.0 EM: He published a protocol intended to assess ingredients using something called the rabbit ear method. Do you know what the rabbit ear method is?
0:06:45.4 EC: I do. And it disturbs me.
0:06:49.8 EM: It disturbs me too, which is also a reason while the cruelty-free badges that you'll see on products use the rabbit. Because rabbits have long been used for cosmetic testing and chemical testing, and the rabbit ear method is where you take a white male... White whatever... An albino male rabbit because of their pore size is larger, and you test these products or these ingredients inside of their ear and you sit back and you wait for some kind of reaction. And they are used because it is thought that there's an incubation period that's a lot shorter, so you'll see a result sooner than you would in a human subject. So he used this rabbit ear method to... And apply these ingredients one at a time, by the way, and from that he deducted on a scale from zero to five, how comedogenic this ingredient was. Zero was good, five was bad. So after this scale, scientific papers started to be published using this method and generating data about how likely a single ingredient was to cause blackheads or comedones. In this, a great example was... Or an early telling of the failings is Lanolin. So when they first started testing Lanolin, Lanolin was good, it had a zero rating. But Lanolin derivatives were really bad, so they would have a four or a five. I should also note that an ideal situation is for topical... The theory is. Topical use product should be from zero to two, anything higher than two, is bad.
0:08:29.8 EM: Awesome, right, so this... Now we have an explanation, a guideline to follow from 1979. Great, except experienced formulators noticed that this posed predictive data, it was not translating to real world anecdotal human experience, this wasn't making sense.
0:08:47.4 EC: You don't say. That's bizarre.
0:08:48.0 EM: Rabbit ears weren't being compared correctly to skin, human skin. Those things weren't the same.
0:08:54.5 EC: Isn't that something? Wow. Weird right?
0:08:56.3 EM: So yeah, I was like, "No, this isn't making sense to what I know to be true." You're saying this is bad and it's not bad from what I'm seeing, or you're saying this is good, and it's not good from what I'm seeing. And then, there were scientific papers on the same ingredient that would contradict each other so let's just use coconut oil 'cause we're gonna talk about it in a minute. It would be coconut oil in this study was good and coconut oil in that study was bad. So that sucks. That and a lot of other things led to Kligman state or conclude that rabbit ear tests should or could produce misleading results. So that in 1996... So what is that? 17 years later, he was like, actually, maybe that was not the best way to do things. [chuckle] So they started testing on humans. In Europe, the animal testing or the rabbit ear test is banned, and I think there's still a couple of places in the US that use it, but majority use is human test. So, would you guess that the comedogenic potential of an ingredient would be tested on human faces?
0:10:09.1 EC: I would assume so.
0:10:11.4 EM: You would assume so, right? Makes sense, 'cause if this is a facial product, we better test it on the face because we know the skin everywhere is slightly different there.
0:10:20.6 EC: Right.
0:10:22.0 EM: And we've learned some things since 1979, rabbit ears aren't quite the same as human facial skin, so let's move, let's evolve from that. You know?
0:10:32.8 EC: You'd think, you would think.
0:10:34.9 EM: But it's the method in which that they do this test is they take this... Pretty much a Band-Aid that has this transdermal release of this specific ingredient and they put it on the backs of adult humans with large pores on their back, by the way.
0:10:52.6 EC: Which is so crazy, anyone that is well-educated in skin care knows how much of an enormous difference there is between the skin on your face and all of those complexities and the skin on your back... Amen. Sister Amen.
0:11:10.4 EM: So this golden rule that we're holding true and we're wagging our fingers at these ingredient decks is a result of contradictory studies performed on rabbit ears or people with... Not everyone's back qualifies, by the way. Only people with large pores on their back qualify. What the heck? So with that, there's a really cool... It's not cool, it's kind of like... It's interesting on acne.com, there is a summary or a summation of these things. And I just wanna kind of review 11 of these studies that were performed to show the contradictory things. So one study found that ingredients that were high in the comedogenic scale become non-comedogenic when they're diluted as they are in many products. So that's good to understand, especially when we're looking at... I keep saying coconut oil, but that's true. So if we have a product, we'll get into coconut oil and fractionated or refined coconut oil too, but when they're combined with things like lactic acid or glycolic acid, they're no longer comedogenic. Another study determined that ingredients that report clogging on rabbits didn't affect humans in the same way. So if these studies done from 1979 to 1976 showed an ingredient was comedogenic and has been blacklisted since then, yet still hasn't been tested on the back of someone with very large pores. [chuckle]
0:12:45.9 EM: Then we're just still, again, wagging our fingers at that ingredient. At one point it was determined that if the active ingredient in a product were comedogenic, you should avoid it, until they did a study that showed all of the active ingredients in sunscreen were non-comedogenic, but the overall product was comedogenic. We won't say brand names, but it's a very well-known brand. In other words, the inactive ingredients were to blame, so the fillers and the alcohols. And yet another study found that even if a product is non-comedogenic, 'cause remember we see that all the time, this product is non-comedogenic, that product is non-comedogenic, that it can still cause skin irritation, and we know skin irritation can cause acne.
0:13:30.5 EC: And I just have to say, on that one in particular, I have the same issue with this comedogenic scale as I do with facials that are basically in a box, pre-made facials. Everyone's skin type condition is so different, and just by applying these same rules to everything, it just... It can't apply. And so, sure, maybe this product is quote, unquote "non-comedogenic" to someone out there, sure, but to someone else with totally different skin conditions, totally different skin type, has a completely different situation overall going on, different diet, different behaviors, different lifestyle, of course, that could still cause skin irritation, it completely depends on the person. And, yeah, that would cause acne, meaning the whole thing is a moot point. It drives me nuts, man.
0:14:21.7 EM: It drives me nuts too, especially when you're looking at acne, which is such a sensitive thing, Oh, naturally, I'm gonna use an acne line on someone who has acne, but if you come at me with a benzoyl peroxide or salicylic, my acne is gonna get worse. My acne, my break-out, my comedones respond to hydration, in the form of hyaluronic acid, but also in moisturizers, thick moisturizers, comedogenic moisturizers. [laughter] But it's because there's a... Well, we can get in... That's a whole other podcast. But it's basically the message between acid mantle and sebaceous gland, that's destruct-ant, anyways. Let me tell you about this most recent study. This most recent study is the one that I find is on to something. It's kinda like this "Aha" study. But it talks about that there are a crazy number of variables involved in whether an ingredient will clog pores, like the other ingredient it's combined with, the concentration of the ingredient and the material used to dissolve it. One thing that is not considered in any of these studies is the co-factors, like we're talking about.
0:15:32.9 EC: Yeah. How they work together.
0:15:33.9 EM: How what's going... The individual cause of the acne in the first place. Is it hormonal? Is it dry acne? I live in Colorado, and that's a huge problem here. Is it an overproduction of oil? What's the problem here? What is the root cause? Not just... And it could be beyond a topical solution, and do we need... Is it inflammatory? And we need to apply anti-inflammatory agents like... That's a drum roll. Like coconut oil, which can be extremely anti-inflammatory and anti-bacterial. So coconut oil is bad. Coconut oil has a bad rep when talking about comedogenic. It is avoided at all costs. Would you say?
0:16:17.6 EC: Yeah, that. And sometimes coco butter. I think coco butter can get a real bad rep too.
0:16:23.5 EM: Absolutely, but guess what? Coconut oil in 1982 had a rating of 1.8 on humans. On rabbit ear method, it was 2.9.
0:16:35.5 EC: You better do it coconut oil.
0:16:37.6 EM: Okay. Remember, zero to two. So it was fine.
0:16:41.2 EC: Yeah, yeah.
0:16:41.3 EM: And then in 1989, coconut oil had a rating of 2.5, so I'm not sure what happened in those seven years, but it doesn't address what else this person with the very large pores on their back was eating, what their hormones were, what their age was, what part of the country they lived in. And then, there's also a difference between coconut oil and fractionated coconut oil. So it's kind of like... I'm sure we've all been out for crab legs, and we have dipped our crab legs into the most amazing golden sauce, decadent, rich, clarified butter. And so, clarified butter is when you melt butter and you remove the heavier solid portion of it. It's the same thing in refined or fractionated coconut oil. It's when it's been heated to a certain point, but you're still protecting the integrity... The nutrient density of the ingredient, but then you remove a lot of that solid form and you have a thin, more liquid form left. So that fractionated or refined coconut oil, doesn't talk about that here. So products that contain that... In fact, one of my good friends, she developed a line... I don't know if we should say it or put the link in the bio, but it's called Clean coconut. And I was like, "Girl, no one's gonna get that." [chuckle]
0:18:03.6 EM: They're so scared of coconut oil, I would think that over. But dang, if it doesn't work. It's a beautiful product that works really well, and for some of those inflammatory things, we need something inclusive, especially now that we've got this maskne and the tactile disruption to our microbiome that these masks are providing, something inclusive like a coconut oil, not every day, but in those certain circumstances might be actually very beneficial.
0:18:31.3 EC: So in summary, Emily, what are your thoughts on the comedogenicity scale rating system?
0:18:38.1 EM: You know, I see where they were trying to go with it, and I think that well-intentioned, for sure. You wanna give the people a basic knowledge of certain ingredients and how they perform on the skin. Did they really do that well overall? Me personally, I'm gonna say no, just considering the ears and the backs and all of that. So it's like I see where they were going, and is it something to be aware of as you're practicing on your clients? Of course. I think looking at your clients, looking at the uniqueness of their skin, what they're trying to achieve, that is gonna be the most important thing, and then when you're looking at your products in your ingredients, really take a deep dive into what is contained within your products, and what are you trying to achieve for your clients, and don't just use this scale as the end-all be-all. Just if something is rated zero or a five according to this scale, that doesn't mean that you cannot use products that have those ingredients because it's just, it's like a basic resource that maybe it's helpful, but maybe it's really not, and you really just need to do your own research and do what's best for your client and think a little bit more independently versus just having a scale to refer to.
0:20:05.4 EM: Would that be nice if this was the end-all be-all? Sure, man, my job would get so much easier if I was just picking products according to a scale and doing these... The anti-aging facial where it's the same for everyone and your skin is gonna look like it's 18 again, but it's like, that's just not reality. And so those are my thoughts. It was an interesting concept. A little outdated. Not necessarily the most accurate.
0:20:36.1 EC: A for effort.
0:20:37.6 EM: A for effort.
0:20:39.7 EC: A for effort old Kligman.
0:20:40.1 EM: Yep. He tried.
0:20:41.8 EC: I would so echo that. Everything you said. Oh, the other thing I want to add to that is that I forgot to mention that these human trials, this human test subjects with very large pores on their back, the testing was over a period of four weeks to six months. So if you're using a product, you're asking about a product, if you're asking your peers about a product or if you're looking at a client, you're reviewing their products, understand that if they use it for a day or a few weeks, this is probably not the culprit of causing them acne. And it's so much more than that, like Emily said. So for you posters who are asking the question, girl or a man, you got this. It's not just the product that you should be looking at. Yes, it is one part of the formula. And for those of you who are commenting, be careful not to be too self-righteous about that because it's not a one-size-fits-all. And with that, we would like to bid you adieu and tell you to keep your ears posted for our next Two E's in a Podcast, and for information on how to connect, check the show notes. Thank you.
0:21:50.2 EM: Thank you guys.
0:21:51.2 EC: Thanks for joining us today. If you like what you hear and you want more, subscribe. If you wanna belong to the only all inclusive Association for estheticians that includes professional liability insurance, education, industry insights and an opportunity to spotlight your six skills, join at ascpskincare.com. Only 259 per year for all this goodness. ASCP knows, it's all about you.