The Right Way to Layer an AHA or BHA and Retinol in Your Skincare Routine

Are you using these active ingredients correctly?
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As anyone interested in skincare knows, active ingredients are our friends.

Two of the most proven ones are acids and retinol:

  • Acids are AHA and BHA exfoliants. The AHA (alpha-hydroxy acid) family includes glycolic acid and lactic acid, while there's just one BHA (beta-hydroxy acid), salicylic acid.
  • Retinol is a member of the retinoid family of vitamin A and vitamin A derivatives. Active vitamin A (retinoic acid) is prescription-only, but retinol is available over-the-counter.

Both acids and retinoids do everything from resurfacing the skin to fading dark spots to softening fine lines and wrinkles. 

So if one active is good, wouldn't a routine with two actives be even BETTER? 

Well, not so fast! You may have heard that acids and retinol don't get along well together—and you'd be right. 

Fortunately, you don't have to choose between these skincare ingredients. It's fine to use either an AHA and retinol, or a BHA and retinol in one skincare routine. (If your skin is very tolerant, some people like to use all three, although it's not really necessary.)

But here's the catch. They MUST be applied at the right times, in the right order, to minimize irritation and get the best possible results. 

Allow me to explain...

Why Acids and Retinol Don’t Mix

Applying a retinol right over an acid diminishes the effectiveness of both ingredients.

Before we get into the "how," I want to briefly touch on the "why"—the reason you shouldn't use retinol and acids at the same time.

Irritation: First of all, there's more risk of irritation when you're using two strong exfoliators at the same time. This can disrupt your skin's barrier and leave you inflamed and sensitive.

Impaired conversion of retinol: Second, retinol doesn't work so well on acidic skin. As a derivative of vitamin A, it must be converted into retinoic acid by your body in order for your skin to be able to use it. This study found that the "hydrolysis reaction is greater at neutral pH," which means the conversion process is more optimal on non-acidic skin.

Inactivation of acid: On the flip side, acids penetrate better at a lower pH (see this study, for example). So if you're layering a retinol with a higher pH over an acid, it might neutralize the acid—bring up its pH—and make it less effective. It's also a waste of good product!

Acid and Retinol Routines to Try

Okay, ready to see how you can incorporate both active ingredients into your routine? 

Here are some options you can try... 

Option 1: Acids in the Morning, Retinol at Night 

Apply acids and retinol at different times of day.

The least risky way to use acids and retinoids is to apply them at different times of day. 

Does it matter which one you use when? Well, prescription retinoids should always be used at night because they can break down in light and make your skin more sensitive to sunburn. So if you're on Retin-A, you should definitely apply your acid products in the morning. 

Over-the-counter retinol doesn't cause the same sun sensitivity, and some of the newer formulations may be photostable enough to wear in the daytime underneath a good sunscreen.​ However, most dermatologists still recommend using retinol at night.

Personally, I always like to use a AHA or BHA in the morning to get off any flaky dead skin cells caused by my retinoid at night. Exfoliating in the morning also gives you a nice smooth canvas for makeup.

Products to try: 

Option 2: Alternate Nights 

Apply acids and retinol on alternate nights.

Another option is to only use your active products at night, one active at a time. That could mean: 

  • Acids one night, retinoids the next.
  • Two nights of acids, third night retinoids.
  • Two nights of retinoids, third night acids.
  • Acids one night, retinoids the next, and then a night off with just moisturizer.

Or any other combination, depending on what your skin can tolerate. 

This is a good way to approach actives if you have sensitive skin, or if you're new to using stronger products and want to gradually build up a tolerance. 

Products to try: 

Option 3: Wait 30 Minutes 

If you must use acids and retinol at the same time, wait 30 minutes in between them.

If you do want to go ahead and use an acid and a retinoid at the same time, you can... but only if you've got time to wait in between layers! 

It doesn't really matter which one you apply first; just go with the one that has the lightest texture. Typically, this is the acid. For example, I would put on products like Lotion P50 or The Ordinary Lactic Acid 10% + HA first, because they have a thin consistency.

Then, wait a good 30 minutes to allow your skin's pH to return to normal. 

Once the waiting time is up, you can apply your second active on top. 

Usually, this is the retinoid, and most will have thicker texture. For example, Drunk Elephant A-Passioni is creamy, while A313 Vitamin A Pommade is a rich salve.

There's still a chance the retinoid may not convert quite as well as it would without the acid, but the waiting time should help a lot! 

Products to try: 

Conclusion

Get the most out of acids and retinol by using them at the right time.

I hope this clarifies some of the confusion around acids and retinoids!

I know you want ALL the skin benefits—and trust me, I'm the same way. But in the spirit of protecting your skin barrier and not wasting your money (by weakening or inactivating something), I think it's so important to use these ingredients strategically.

Personally, I've had great results applying my favourite COSRX BHA both morning and night, and Resurface by Shani Darden Retinol Reform a few nights a week. On the nights I'm too tired to wait the 30 minutes, I'll either skip the BHA or the retinol. 

I'd love to hear what works for you!

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