Well, the truth is it’s “more what you’d call ‘guidelines’ than actual rules.” Skincare is personal, so what works for me might not work for you. And that mostly holds true even when it comes it mixing skincare ingredients. If you’ve ever looked up skincare content on Pinterest, Instagram, or TikTok, you may have come across some nice and simple guides that clearly list which skincare ingredients should NEVER be mixed. I know that I’ve seen tons of them. Unfortunately, many of these guides are oversimplified, if not downright incorrect. For example, many of these guides say that you cannot used Vitamin C and Niacinamide together because in a 1960s study, the combination of those two ingredients was shown to potentially cause flushing. However, in the study, the ingredients were both at abnormally high temperatures and at high concentrations (the Vitamin C was also ascorbic acid). Under normal conditions and in the majority of people, these two ingredients are completely fine when used together. There are also products that are formulated with both Vitamin C and Niacinamide in them.
Here in this guide, I’m going to give it to you straight. Most skincare ingredients can be mixed, but that doesn’t necessarily mean they should be mixed, especially if you are a beginner. Although I am often annoyed by the oversimplified guides I mentioned above, I can also see how they can be helpful for beginners. That’s because many of the ingredients mentioned in these guides are more advanced ingredients that should be used with caution anyway. Many of them are active ingredients, such as Vitamin C, BHA, AHA, Retinoids, and Benzoyl Peroxide. These ingredients should always be used carefully because they have the potential to cause irritation or to damage your skin barrier if used incorrectly. Some of them can also cause increased photosensitivity in the skin and must be used with sunscreen to prevent sun damage. Below I will talk more about how to mix these ingredients safely!
Mixing Ingredients in the Same Routine vs. in Different Routines
First, I want to get started with this important distinction. Some guides don’t specify whether or not they’re talking about mixing ingredients in the same routine (aka your AM routine) or different routines (aka your AM routine vs. your PM routine or your Tuesday routine vs. your Friday routine). If you are thinking about mixing a lot of different active ingredients in a single routine (aka applying them to your face all at once), then this is where you might need to stop and reconsider things. It’s much easier to overwhelm your skin and accidentally damage your skin barrier if you start using a bunch of active ingredients in the same routine. Even if you are using several different actives in different routines, it is still pretty easy to overdo it, unless you know your skin extremely well. The biggest issue with mixing active ingredients is that you’re increasing the potential for damaging your skin barrier and causing irritation. This is why it’s important to be careful with any active ingredients, no matter how many you’re using, but especially if you’re using more than one in the same routine.
Overall, I think it’s best to lean towards ‘mixing’ ingredients in different routines. I’ve learned this the hard way. If you aren’t sure if you should use your AHA and BHA at the same time, just be cautious and use one on Monday and the other on Tuesday, or something like that. If you are new to actives, it’s also best to err on the side of caution and use the active less often than you might think. For example, with retinoids, I started off using Tretinoin (a prescription strength retinoid) once or twice a week and gradually worked up to every other day. I also use other active ingredients, but in general, I don’t use them as part of the same routine. I use a gentle AHA, but I only use it once or twice a week, and not on the same nights that I use Tretinoin. Additionally, I use a Vitamin C every other morning, but it contains a Vitamin C derivative, (not ascorbic acid) since I know ascorbic acid is too harsh for me. I also use Niacinamide (which I wouldn’t consider an active) every day, probably in every routine because it’s in so many products these days. I’ve never experienced any flushing from using Niacinamide, even when I was using it with an ascorbic acid Vitamin C serum.
Ingredient Mixing Guidelines
Now let’s get into the specifics. Again, these are meant to be guidelines not rules. I believe that skincare is incredibly personal and I’m not here to tell you what to do or what will work for you skin. Only you can know that. And although I’ve tried not to oversimplify in this chart, I have to admit it is still a bit simplified. In reality, a lot depends on your skin as well as the strength of the ingredients and the formulations of the products you are using. I cannot account for all of that in this chart, but I still hope it can help you understand a little bit more about how and when to use different ingredients.
| Ingredient 1 | Ingredient 2 | Can they be mixed in the same routine? | Can they be “mixed” in different routines? | Notes |
| AHA | BHA | With caution. I’d recommend using a single product that contains both if you want to use them at the same time. | Yes. You can use BHA in the AM and AHA in the PM. This could still be too harsh for everyday. | AHA increases photosensitivity |
| Retinoids | AHA or BHA | I wouldn’t recommend this especially for beginners. Retinoids can be very harsh, though it depends on the retinoid you’re using. | Yes. Personally, I would use them on alternating nights, or less often. | Retinoids aren’t photostable and AHA increase photosensitivity |
| Vitamin C | Retinoids | With caution. If you want to do this, I’d recommend using a gentler Vit C dervative (not ascorbic acid). | Yes. It’s probably better to use Vit C in the AM and Retinoids in the PM anyway. | Retinoids and Vit C (ascorbic acid) aren’t photstable |
| Vitamin C | Niacinamide | Yes. Most people will experience no issues from mixing these two, even beginners. | Yes. | Ascorbic Acid is not photostable |
| Benzoyl Peroxide | AHA or BHA | I wouldn’t recommend this, especially for beginners. BP can be very harsh and drying. | Yes. Personally, I would use them on alternating nights, or less often. | BP and AHA increase photosensitivity |
| Benzoyl Peroxide | Retinoids | I wouldn’t recommend this, especially for beginners. BP and retinoids can both be very harsh. | Yes. Personally, I would use them on alternating nights, or less often. | BP increases photosensitivity and retinoids aren’t photostable |
| Niacinamide | AHA or BHA | Yes. Most people will experience no issues from mixing these two, even beginners. | Yes. | AHA increases photosensitivity |
Conclusions
Hopefully this helped you gain a better understanding of which skincare ingredients shouldn’t be mixed and which ones can be! I think that the main takeaway here should be this: things aren’t always as simple as they sound, and they’re almost never as simple as they are made out to be on social media. And the other takeaway should be this: always be careful with active ingredients, especially if you are using more than one! Actives can be tricky to use, even if you are only using one. So in my opinion, it’s always best to approach them with caution. When in doubt, space it out, and don’t use more than one active at a time. But if you’re a pro with actives, then you do you, and just do whatever you know works for your skin! As always, keep in mind that I am not a dermatologist or a skincare professional and this post is mainly based on my personal experiences.
If you enjoyed this article, be sure to check out my other Skinqueries posts where I delve into common skincare questions!
- Does Collagen in Skincare Actually Do Anything?
- Damaged Skin Barrier 101 and the Best Barrier Repair Products
- Do I Need to Apply (and Reapply) Sunscreen Indoors?
- Causes of Skin Redness and What Skincare Can and Can’t Do to Help
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