What can you not mix with retinol to make sure you don’t cancel it out? Cause your skin irritation… or worse… ageing! I’m a scientist and here’s what not to do.

Do Not Use Your Anti-Ageing Retinol Serum With…

In Anti-Ageing & Protective Skincare by Cheryl Woodman MChemLeave a Comment

What can you not mix with retinol?

Great question my friend 😀

Because pairing up anti-ageing skincare actives can go as wrong as…

Mixing red wine with milk.

Brad Pitt dating Golem…. (not that there’s anything wrong with Brad Pitt ;))

And melting chocolate over Broccoli. Don’t do it (!)

I’m here to make sure you do not mix retinol with the wrong skincare actives.

Psst – let me be super clear – these other skincare actives can be awesome for your skin – just not when used WITH retinol.

It’s all about finding your perfect pairing. 

Like Michelle and Barack Obama 🙂

Here are the 5 dangerous, no-go mixing combinations you must avoid when using retinol. Your what can you not mix with retinol exposé.

So, let’s dive right in 😀

What can you not mix with retinol to make sure you don’t cancel it out? Cause your skin irritation… or worse… ageing! I’m a scientist and here’s what not to do.

1. Lactic Acid and Retinol

Ooeee. Both are awesome skincare actives. In fact, I love me some lactic acid. Lactic acid is actually a natural component of what’s called your skin’s natural moisturising factors meaning it can be super hydrating as well as exfoliating. Those two words usually don’t attract each other 😉

Q: What can you not mix with retinol?

A: Lactic acid.

It’s for two key reasons;

  1. Lactic acid and retinol work best at different pH levels
  2. Lactic acid and retinol are both exfoliating actives

Let’s break this down eh.

Skincare actives which are water-based have a pH level. That’s a measure of how acid or alkaline they are when dissolved in water.

Think of how lemon juice stings. That’s because it’s super acidic.

But psst – not all things acidic sting – actually your skin’s also slightly acidic. And you’ll find your skin being super uncomfortable when it’s not.

Lactic acid loves to be at a pH around 3.8.

Most retinoids have best stability at about pH 6 to 7.

Psst – if you’re confused about the difference between retinoids and retinol – make sure you check out this blog.

And so when you use lactic acid with retinol – it has super potential to make retinol much less effective. That means fewer anti-ageing benefits for your skin. Booo.

Lactic acid and retinol are also both exfoliating actives. Removing extra layers of your skin quicker than they would be coming off naturally.

That’s fantastic for helping prevent fine lines and getting glowy, bright skin.

But – exfoliate your skin too much and you’re going to look as shiny as a tin foil… your skin’s also going to get super irritated, dry, damaged, red… and yes, aged too.


Using two exfoliating actives together continually is like having that second helping of deliciously gooey chocolate fudge cake. You know you shouldn’t have it. You’re WAY too full. But this chocolate fudge cake, well, it’s way TOO yummy and tempting. Somehow the forks already making its way to your mouth. Your tastebuds are going ping, ping, ping. Yes, yes, yes. Then 5 minutes later your tummy’s in instant regret mode.

Omgosh I’m sooooo fulll. Eugh.

What can you not mix with retinol? Low pH exfoliating actives like lactic acid. Lactic acid and retinol are a no-go.

2. Retinol and Vitamin C

Psst – I go into this super star anti-ageing pairing in-depth in my recently launched AgeLock course. If you enrolled this October then you know exactly how to mix retinol and vitamin C the right way – for your best and biggest anti-ageing benefits – wahoo. And if you missed out – don’t worry, you can sign-up here to be the first to know when it’s next released.

Q: What can you not mix with retinol?

A: Vitamin C as ascorbic acid.

But psst – there’s a way you can mix these two anti-ageing superheroines because spoiler alert – there are other kinds of vitamin C.

More on this inside AgeLock as I show you step by step how to make your best ever, anti-ageing skincare routine.

However, for now, know that you should not mix retinol with vitamin C as ascorbic acid because;

  1. Both retinol and ascorbic acid can be exceptionally irritating skincare actives
  2. Retinol and vitamin C as ascorbic acid have very different pH levels (yes – just like lactic acid and retinol)

Let’s unpick #1 some more eh.

Ascorbic acid is a highly irritating skincare active. Even if you’ve used it before and have seen zero noticeable irritation, the more times you use it, the more you’re running down your skin battery.

There’s also this concept called inflammageing. 

Ageing of your skin caused by ongoing low-grade inflammation that’s not noticeable to your naked eye.


Using layer on top of layer of irritating, anti-ageing skincare actives can actually cause your skin premature ageing. It’s shocking right.

Retinol can be highly irritating, especially if it’s not in a soothing formula – it’s one reason why companies like The Ordinary have so many different retinol formulas.

And guess what… ascorbic acid can be highly irritating too.

Use retinol and vitamin C as ascorbic acid together and it’s like getting your bikini line waxed twice, the second time, straight after the first (!) ouchy.

What can you not mix with retinol? Do not mix retinol with vitamin C when it’s used as ascorbic acid. You can tell if your vitamin C serum is an ascorbic acid serum by looking at the ingredients list – does it say ascorbic acid? If it does, do not mix retinol with it.

3. Retinol and Salicylic Acid

I bet you can already tell me why you can’t mix retinol with salicylic acid eh.

You’re so savvy!

It’s because, just like you’re guessing right now, salicylic acid has a very different pH level to retinol. And yes, yes, yes – both are also exfoliating actives.

This do not use retinol with salicylic acid ingredient pairing is exactly like lactic acid and retinol. But this time around it’s way more potent.

That’s because salicylic acid is extra irritating versus lactic acid.

Q: What can you not mix with retinol?

A: Salicylic acid.

Steer clear my friend.

Super sneaky pro-tip: the first time you use retinol with salicylic acid you might think you’re seeing great results – that’s because exfoliating actives can give instant brightness, glow and smoothing. However, with time, irritation builds and boom – you’re actually pro-ageing your skin. You just don’t recognise you’re doing this yet because it doesn’t show straight away.

Now you know better my friend. Now you’re a pro 😀

What can you not mix with retinol? Do not mix retinol with salicylic acid – they can make each other less effective and could cause you inflammageing.

Psst – there are some fab anti-ageing actives that pair up awesomely with retinol – I’m name dropping some in my free, 5 best anti-ageing actives cheatsheet. Click here to get yours now.

4. Retinol and Benzoyl Peroxide

You said what!?

Retinol and benzoyl peroxide.

I have to admit right here, right now I’m really not a fan of benzoyl peroxide and this is another huge reason why.

Let me explain by kicking off with the nuts and bolts. Do not mix retinol and benzoyl peroxide because;

  1. Benzoyl peroxide is an oxidant and retinol is highly oxidation prone (aka prone to going off)

Q: What can you not mix with retinol?

A: Benzoyl peroxide.

Wowzer eh. That’s a bit of science gook right there.

Don’t worry my friend this is super simple.

First up know this – benzoyl peroxide is an oxidant meaning it makes things go off quick, just like how an apple browns. That’s oxidation 🙂

You can think of retinol like Sheldon from The Big Bang Theory – super sensitive 😉

Retinol likes things its way and if you don’t give retinol what retinol wants – it will not anti-age your skin. Instead, it’ll expire, go to sleep and never be seen again.

This is because retinol is actually a super unstable skincare active.

If you want retinol benefits you need to give your retinol what it wants and benzoyl peroxide is the opposite of that.


Retinol needs and loves antioxidants not oxidants.

Some studies show when retinoids get mixed with benzoyl peroxide – 24 hours later there’s less than 95% of the retinoid left. 

What can you not mix with retinol? Do not mix retinol with benzoyl peroxide because benzoyl peroxide is like a Dalek to retinol, shouting ‘exterminate, exterminate, exterminate’.

5. Retinol and Glycolic Acid

It’s our final ‘do not mix retinol with’ Brad Pitt and Golem pairing.

Q: What can you not mix with retinol?

A: Glycolic acid.

These two anti-ageing skincare actives can love your skin beautifully when used separately. But use retinol and glycolic acid together and you could be;

  1. Getting extra irritated skin because both retinol and glycolic acid are exfoliating actives – you’re doubling up here accidentally – oops (!)
  2. Cancelling out some of retinol’s anti-ageing effectiveness because retinol likes to be at a higher pH level (remember how we said that’s about 6 to 7) and glycolic acid, well it likes to be around pH 3.6.

Remember how going for two bikini waxes in quick succession isn’t an awesome idea? 😉  Well, using two skincare actives which both have exfoliating benefits or a higher irritation potential, together is also not a good idea. Like melting chocolate over Broccoli.

What can you not mix with retinol? Do not mix retinol with glycolic acid.

And that’s a what not to mix with retinol wrap. Wahoo. Which skin care products are currently ‘sandwiching’ your retinol? 

Psst – use that big green sharing button below to forward this blog on to a friend you love, a friend who’s been in-a-pickle about her skincare 😀