These Are The Skin Care Ingredients You Definitely Shouldn’t Be Mixing


If you’ve decided to level up your skin care routine, but suddenly feel like you need to have a science degree to understand all the AHA/BHA, HAs, retinols, vit-Cs and Ds mambo-jambo; let’s start with a crash course in ingredients you should not be mixing. 

This is important to ensure you aren’t wasting money by using ingredients that will cancel each other out. Or, you know, to avoid burning your face off.

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One crucial thing to remember when structuring your skin routine:  just because two ingredients have the same benefits, i.e. acne-fighting, doesn’t give them the green light to be mixed. Yes, they may be fighting the same fight, but they could also be speaking totally different skin languages. 

Think of it like this: just because salmon and chicken katsu make great sushi roll fillings, doesn’t mean they should be used together. 

And when it comes to complexion flavours, these are the combos that don’t marry well…

Retinol + AHA/BHAs

Retinol (vitamin A) stimulates cell turnover, which essentially means it is getting rid of dead, dull skin cells and replacing them with new ones.

This is a secret weapon for reducing the appearance of fine lines, wrinkles, acne and dark spots.

However, it can be irritating if overused or mixed with exfolating acids such as AHAs and BHAs.  Therefore, the two should never be used within the one skin care regimen. 

bh recommends: Alpha-A Vitamin A 0.5% as a retinol and Paula’s Choice Skin Perfecting 2% BHA Gel Exfoliant as an exfoliating acid.


Salicylic Acid + Glycolic Acid

These ingredients are favourites for removing dead skin cells, however, pairing them together will not give you a double dose of effectiveness. 

Salicylic is best used when treating acne-prone or oily skin, whereas glycolic is more suited to mature skin, targeting fine lines and wrinkles.

bh recommends: Ultraceuticals Ultra Gentle Exfoliating Gel for salicylic and Dr.LeWinn’s Reversaderm Glycolic Cleanser for glycolic.


Vitamin C + Retinol

Both of these ingredients are heroes in their own rights, with vitamin C primarily for brightening and retinol an anti-ageing powerhouse. However, using them at the same time can overstimulate the skin.

You can still use them in the same day, just at opposite ends and never together.

Vitamin A is best used at night, while vitamin C is perfect in your morning routine under SPF.

bh recommends: Clinique Fresh Pressed Daily Booster With Pure Vitamin C 10% and Ultraderm Rapid Retinol Concentrate




AHA/BHAs + Vitamin C

If you love throwing money to the wind, mix these products.

Vitamin C and AHA/BHAs offer amazing antioxidant benefits, however, combining them can throw off the pH balance of your skin which will essentially render them both completely useless. 

If you insist on having both in your cabinet, use separately.




Oil-based + Water-based

Water and oil don’t mix.

Using an oil-based product before a water-based formula is going to stop the water from absorbing into your skin. 

If you are applying your face oil first, you may as well just be covering your face in a shield before you get to the water-based serum.  Vice-versa it’s a-ok, which is why most just abide by the rule of oils last, always.

bh recommends: Sukin Rosehip Certified Organic Oil and Neutrogena Hydro Boost Water Gel

Niacinamide + Vitamin C

For anyone with sensitive skin, be careful of mixing these two together as, again, it can overstimulate the skin and trigger breakouts.

However, used separately, they are both amazing ingredients for conjested or blemish-prone complexions. We’d suggest niacinamide for those with troubled skin, and vitamin C for those who only have the odd pimple every now and then.

bh recommends: Paula’s Choice 10%  Niacinamide Booster and La-Roche Posay Pure Vitamin C10 Serum 

Vitamin C & Benzoyl Peroxide

If you’ve been using these two ingredients together, to put it simply, you’re flogging a dead horse. Benzoyl peroxide causes vitamin C to oxidise and you’ll end up exactly where you started. 

Retinol & Salicylic Acid

When it comes to fighting acne, both of these ingredients are going to make a quick and visible impact.

However, resist the temptation of doubling down because when they are used together, the result will be red, dry and irritated skin, potentially worsening your pre-existing congestion.

To avoid the two superhero ingredients being too harsh for your skin, stick to using your retinol at night and your acids during the day.

bh recommends: SkinCeuticals Retinol 0.3 as a retinol and Paula’s Choice Clear Regular Strength Anti-Redness Exfoliating Solution with 2% Salicylic Acid as a salicylic acid


Soap-Based Cleanser & Vitamin C

According to dermatologist Leslie Baumann, when it comes to your skin’s ability to absorb vitamin C, the cleanser you are using pre-application is making an impact.

As vitamin C is more effective when formulated with a low pH, when you are using a soap-based cleanser (which contains a high pH) you are limiting your skin from drinking up all the goodness.

So in order to get a better bang for your buck (because let’s face it these serums ain’t cheap), enlist a salicylic or glycolic-based cleanser in the morning before you apply your vitamin C. 

bh recommends: Eau Thermale Avène CLEANSING FOAM as a soap-free cleanser and BOOST LAB Vitamin C Brightening Serum as a vitamin C

Two different products with the same actives

Aside from the fact that there’s simply no real need to double up on the same active ingredient, you might also be tempting fate when it comes to disrupting your skin barrier. 

An example of one such risky double up that you may not realise you’re making is applying a salicylic acid face mask and then finishing with a BHA-containing serum. Stick to one, your skin will thank you for it. 

Main image credit: Getty Have you had any issues mixing ingredients?

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Comments 135

  1. This article seems to misinform. AHA and BHA are often recommended by professionals to be used in complement to each other because they have different solubility (one is water soluble and the other is oil soluble). They target two different skin issues

  2. Good to know.
    I use Retinol ocassionally but it dries me skin out so its not a frequent user for me.
    Not sure I use much vitamin A its in a serum I have but not used the 2 together

  3. Me too, I know to use my Vit C in the morning and my retinoic acid in the evening but I wasn't sure how they work with some of the other products in my arsenal. I'll have to come back and check how they all fit together.

  4. This has got me thinking regarding my cleanser because it's quite an 'active' cleanser and its a real fave of mine as it seems to do amazing things for my skin but maybe I should be switching to something super gentle when using more active serums/creams etc!

  5. Using products from the same brand should work better but even then there are some exceptions so best to research each product you do use and if it is compatible with another product.

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