Why You Shouldn’t Mix These Skin Care Ingredients — & When You Can

Why You Shouldn’t Mix These Skin Care Ingredients — & When You Can

We’ve all heard conventional sayings like “don’t mix neutrals” and “don’t pair red wine with fish.” Personally, I don’t really abide by any of these things. I think you can rock black and brown, and I don’t see anything wrong with mixing your favorite wine with your favorite dish, even if they don’t “go together.”

However, when it comes to skin care ingredients, I am a little more of a stickler for following the conventional rules of what not to mix. I’m all for experimenting and doing what works, but I also know that there are some instances where conventional wisdom is really the best way to go.

There are tons of blogs full of well-intentioned misinformation out there, so to help you out, I’m going to list a few skin care pairings that you typically should NOT make.

When it comes to skin care, there are some instances where conventional wisdom is really the best way to go.


1. Vitamin C + Niacinamide

Let me preface this one by saying that some people can (and do) use these side-by-side without issue. If you’re one of those people, keep on keepin’ on, my friend.

In general though, this isn’t an ideal mix of skin care ingredients if you have sensitive skin. The combination of niacinamide and ascorbic acid (or any acid, truthfully) can lead to the formation of niacin, which can cause an uncomfortable redness and temporary rash known as flushing.

If you’re worried about them canceling each other out though, you can rest assured that this won’t happen. There are a ton of articles that cite this as the reason not to mix the two, but they’re based on seriously outdated research and the unfortunate habit that some people have of just parroting off information they’ve heard without looking into it.

Personally, if I’m ever unsure of the science behind something and can’t find the answers I’m looking for, I turn to KindofStephen. He’s a cosmetic chemist who really knows his stuff, and he’s great at breaking down complicated science into easy terms.

So, if you don’t have sensitive skin, you can test layering these ingredients. If you do, or if you’d rather not risk it, just separate them and use vitamin C in the morning and niacinamide in the evening.


2. Benzoyl Peroxide + Retinol

This is another combo that gets a bad rap for the wrong reasons. There’s a combination of older research and anecdotal evidence floating around that says BP negates the effects of tretinoin, and this is usually the reason given for why you shouldn’t mix the two.

teen acne

There’s newer research that contradicts this reasoning, but I do have another reason for saying that it’s better not to mix the two (unless a derm recommends it for you specifically): unnecessary irritation.

Retinol in all its forms is a gold-standard skin care ingredient, but it also has a tendency to leave your skin dry and/or irritated if you aren’t extremely careful. Benzoyl peroxide is great for drying up those mountainous zits that crop up unexpectedly, and it can help to keep oily skin under control, but it’s also a very drying and potentially irritating ingredient.

I find that it’s best not to mix these two simply because the risk of overexfoliation or seriously dry skin is just too great. It’s better to use one at a time, or do targeted applications instead (e.g., spot treat your chin with BP and don’t use retinol on it that night).


3. Hydroquinone + Any Peroxides

Go ahead and believe the horror stories that surround this pairing because they’re really not overblown or misguided.

I’ve talked before about how hydroquinone can be a useful tool for fading hyperpigmentation, but you should absolutely not use benzoyl peroxide, hydrogen peroxide, or anything that has peroxide in it at the same time.

Hydroquinone works by decreasing the amount of melanin produced in the treated areas and increasing the rate at which the melanosomes (the parts of the skin cell that hold pigment) are broken down. This helps to lighten the skin back to the desired tone.

However, when you throw peroxide into the mix, you run the risk of staining your skin AND causing serious irritation. While you can usually wash away the staining with soap and water, this is a combo that you should definitely avoid because it could also lead to hypopigmentation, which is when you get patches of skin that are under-pigmented instead of over-pigmented.


4. Sunscreen + Anything

I’m NOT saying that you can’t layer things over or under your sunscreen here. You totally can, and you probably should.

mix skin care ingredients

What you shouldn’t do is try to mix your sunscreen with any other products. No DIY concoctions of sunscreen + moisturizer or sunscreen + foundation. Prep your skin, apply the right amount of sunscreen, and then layer whatever other makeup you’d like over the sunscreen once it’s dry.

Trying to mix or add anything to your sunscreen can mess with the formula or make you think you’re putting on enough when you’re actually not. Best to just go one step at a time so you stay protected!


Mixing It Up Isn’t Always Best

White after Labor Day? Yes, do it! Animal prints and other patterns? Totally. Throwing cinnamon into your steak marinade? Absolutely.

There are plenty of instances where conventional wisdom is wrong about what you should and shouldn’t mix. When it comes to skin care though, sometimes it’s best to listen to the consensus.

Are there any other skin care ingredients that you’ve been told not to mix? Tell me about them in the comments!


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