Skincare Ingredients You CAN'T Mix?! | Doctorly Investigates

Illegal skincare combos. Never ever use a BHA together with a retinol. Pairing your vitamin C with your retinol? Stop doing that. I would never use the retinol in the daytime. Stop using active ingredients together with your retinol eye creams. It will literally burn your eyes. If you're one of those people who are using a salicylic acid cleanser, BHA exfoliant, and a retinol in the same skincare routine in the evening, stop doing that. There's a lot to unpack in this video here. This is basically going to be our do not mix or do mix video. I've seen, since I started doing social media, hundreds of videos telling you can't mix this with this. You definitely can't mix with this with this. And every single time I'm wondering, where does this information come from? We're going to be talking about specifically what you can and cannot mix. We're going to go through each one in this video here. So let's debunk some stuff. All right, debunking mixing. Here we go. Here we go. So first to kind of preface this, we love her videos. Actually, we've done other videos agreeing with everything that she says, but we want to go through this because there's some nuance to this. There's some good reasons why you may or may not want to do these things, but we want to like fully dive into this and explain why we think what we think. And he said the word why twice in there. And I think that is absolutely everything. I'm coming out stronger on this with the stance of the first rule of skincare is there are no rules in skincare. It is all personalized. It is all deliberate, but it takes knowledge to understand the why. Because once you understand why you cannot do something, you find out why you might be able to it and why it actually might be beneficial for the right person. Like we're not saying that all of these are completely wrong. It's just saying, this is how you take this information and personalize it and tweak it for your skin. So the first combination here is BHA or salicylic acid. And she said retinol specifically, but we might expand that to retinoids. So retinol and BHA. So first salicylic acid, not really a BHA chemically, but I think most of the skincare industry understands BHA and salicylic acid to be the same thing. That's a separate conversation. BHA and retinol. Can you mix them? Yes or no? Yes, you can mix them. You can use them at the same time. Why is it commonly spread that you can't use these together? Well, the reason is because when you use these two together, they're both irritating ingredients, or they both can be irritating ingredients. And so when you use two ingredients together that are irritating, you potentially have the possibility of becoming more irritated. This is true of using alpha hydroxy acid with retinol as well. People will tell you not to mix these as well, but there's no chemical reason why salicylic acid and retinol can't be used together. They don't oxidize each other. They don't inactivate each other. The caveat being, if you have sensitive skin, I would definitely not use these together. Now, interestingly, this is actually a combination of ingredients that not only can you use together, you might want to. We see this, especially in the acne space. There are very common acne cleansers that you would want to couple with your retinoid. A very common acne combination would be a benzoyl peroxide wash in the morning. At night, you'll use a salicylic acid cleanser and then your tretinoin or whatever retinoid for your acne. So they have complementary benefits, especially in the acne space, limiting factor irritation. Next up, retinol and vitamin C. Can you use these together? Why or why not? So I guess it depends on when. So retinol and vitamin C would have to be an evening time routine here, right? Because retinols do or can break down in the light. Despite some controversy around that, most of them will. So retinols break down at light. Vitamin C, can it be used in the evening? We talked about in another video. Actually, yes, you can. So both of these might live in your evening routine. Why can't you use them both together? Is it irritation again? It might just be that irritation is a limiting factor. So there's no reason again, why you can't use this together. Now, when you look at skincare in general, two relatively unstable ingredients. So retinol also needs to be stabilized. It's something that oxidizes pretty quickly. It's something that becomes inactive in certain temperatures with light exposure. And so a lot of times brands encapsulate their retinol to make it more stable over time. Then you look at vitamin C, especially the L-ascorbic acid form, also very unstable, can become oxidized quickly, become inactive quickly. And so when you use two ingredients together that are relatively unstable, there's a potential that they could have issues, but there's no chemical reason why these two ingredients can't be used together if they're stabilized in a formula. And that's why your cosmetic chemists and cosmetic formulators will take these ingredients together in one formula and put them in the same formula. And they are still stable over time. They're still effective over time. And they also do sensitivity testing to show that it's not causing irritation. And so they can be used together. It's not an absolute hard and fast rule. And there's really no reason why you can't. Preferred method to use these would be to use them in a product that already has them formulated together. We'll list some below because yes, they do already make these products. Additionally, if you were going to use them, it's the same rule for vitamin C, specifically L-ascorbic acid that lives everywhere. I would try to make sure that this ingredient is put onto clean skin, probably ideally dry, then let it set before moving on to any other step in your skincare routine. Because it's not just retinols. Vitamin C, L-ascorbic acid, and anything might destabilize L-ascorbic acid. So just let it set, then move on to your next steps in skincare if you're not using it in a dedicated product. The next one, never use retinol during the day. This is an interesting debate, okay? Retinol, again, unstable in light for the most part. Caveat here being that there are retinoids, like adapalene, which are stable in light. There are also newer forms of tretinoin, which are encapsulated, or they're formed in such a way that they are stable in light, like altrino you can use during the day. You have retinols that are encapsulated that are safe to use during the day. I think CeraVe has like a daytime cream with retinol in it. And what they do is they actually show over time that even with a light exposure that the percentage of active in the product is still there. So yes, there are stable forms of retinol, but most forms of retinol, most that we still formulate with today in the lab, in most skincare products, is not light stable. So I think that I agree in some ways, and unless you know that your retinol is light stable, most of the time you shouldn't be using it during the day. Now I think this is funny for me and personal to me because I have always been a proponent for the daytime retinoid. Not like you should do it, but that if you're using the right one you can. That's your exception to the rule. The rule here is yes, avoid retinols in the daytime because it will probably degrade them and break them down, just as an overarching theme. But again, the more you know, the more you can personalize it, be deliberate. You would be absolutely correct to generalize and say don't use retinols in the daytime. So I don't disagree with her as much as I did with the other ones, but you could again tweak it, use an adapalene, use a micronized tretinoin in the daytime if it fits your life a little better. I have a ton of the studies bookmark on the daytime UV exposure on stabilized forms of retinoids. It is a generalization. I don't disagree with her necessarily, but there are exceptions to this rule. We'll put some links below for the studies. So the next one, using exfoliating actives with retinol underneath the eye. This one is limited by irritation and I think you have to be super super sensitive around the eye. So using exfoliating acid around the eye in general, using a retinol around the eye in general can be very irritating for people. You use these two together, you run into more risk. So unless the product is specifically an eye cream that's been tested as an eye cream underneath the eye with these two ingredients, I definitely would be careful and probably not recommend being too harsh on the eyes. And then the last question is do retinols in general cause dry eye if they get close to your mammobian glands? Potentially yes. Yeah, potentially. I do believe it's more exceptional than certain, even a single study, there was a study that showed like everyone got dries from retinol eye cream. And I think that's very uncommon in the real world, but it's possible. And I think maybe a common also extrapolated is just overall active ingredients around the eyes. Can you mix other active ingredients with retinol around the eyes? Yes. Like it depends how you want to encompass that term active ingredients of vitamin C and retinol. Yeah, but that can be irritating. So be very, very careful with that combination and the less irritating that complementary ingredient is like you move down to peptides by all means, add that active ingredient to your retinol around the eyes if you're already tolerating retinol. So be careful with irritating ingredients, especially acids around the eyes. I'm pretty, I'm a little bit more, what do you call that? Laissez-faire. Laissez-faire. I'm a little more laissez-faire with your skin. As long as you know your skin, I would be very, very cautious with acids and retinol around the eyes. You're probably going to irritate it. The last point, if you're using BHA cleanser, BHA and retinoid in your routine, this kind of goes, I think this is similar to the first one in the sense that we do this all the time for acne patients all the time. I have patients on salicylic acid, retinoids, benzoyl peroxide, all of these ingredients. And though they are limited again by irritation and you definitely don't want to overdo it. I find that some people that are really oily, very acne prone, can use a lot of BHA and salicylic acid in their routine and use that retinoid and still get away with it. So again, it's one of those things where you have to listen to your skin. If you're getting irritated, back off one of those ingredients for sure, but there's no reason you can't use those together. Right, exactly. Again, potentially complementing benefits in these ingredient profiles, but this ties together the overarching theme. I think of every single combination in this video and that's the potential for irritation. And so the caveat with this whole thing is the potential for irritation strong enough to make a rule. There were words like never, for anyone, ever do any of these things. And I don't believe that's true, especially when it's irritation. So I take this whole category of potential irritation into suggestion. There are rules for certain ingredients like dapsone and benzoyl peroxide. We'll talk about that in another video, but this suggestion, yes, caution with irritating ingredients. It's not a rule for everyone. These can work and play together well. And when we wrote our book, people ask what happened to the book because I'm going to put up a diagram here that's going to show you what you can mix, can't mix, and what you should be cautious with. And so a lot of these irritating ingredients, they're in that caution section, but they're not in the never section. They're in the sometimes section. That's the caution that we're going to talk about. But the ones that you actually can't mix, those are very few and far between. And some people are asking what happened to the book. We had the book, we put it out there. A lot of people bought the book, a lot of good feedback on the book, but we actually pulled the book. The reason why is because a publisher reached out to us to publish our book officially. And so we removed it pending official publication. So stay tuned for that. If you enjoyed the book, you have a first edition copy and you're the first person to ever see it. And we had all these awesome diagrams in there as well. Perfect. So these are our takes on some of the skincare rules, the don't ever mix ingredients, kind of a mixed bag. Some of them you really should work around. Some of them you potentially could work around. But as always, listen to your skin, personalize your skincare, and be deliberate. Please like, comment, and subscribe. And we'll see you in the next video. See you next time.