Are They Dupes?: Paula’s Choice Skin Perfecting 2% BHA Liquid Exfoliant VS Cosrx BHA Blackhead Power Liquid

by Gio

Ask any skincare guru what the best BHA exfoliant out there is and they’ll say Paula’s Choice Skin Perfecting 2% BHA Liquid Exfoliant.

For years, it literally had no competition. Everything else either had too little BHA or a pH that deactivated it. But now, Cosrx BHA Blackhead Power Liquid is threatening to knock its off its throne.

Those who tried it swear the Korean newcomer does a better job: it works faster, it’s gentler and doesn’t leave your skin an oily mess.

Should you switch?

BHA: Salicylic Acid VS Benzyl Salicylate

If you did your skincare homework, you’ll know that in skincare BHA (Beta Hydroxy Acid) refers to salicylic acid.

Salicylic acid is an oil-soluble exfoliant that dissolves the “glue” that holds skin cells together so they can slough off your skin instead than getting stuck in your pores and clogging them up.

While it’s at it, it also gets inside the pores to get rid of all the crap that’s accumulating in there. That’s what makes it such a good fighter against blackheads, whiteheads and pimples.

Plus (yep, salicylic acid has more than one super power), it has anti-inflammatory properties that reduce irritations and redness.

So, with a name like that, you’d think that both Paula’s Choice Skin Perfecting 2% BHA Liquid Exfoliant and Cosrx BHA Blackhead Power Liquid used salicylic acid. But Corsx doesn’t have a drop of it. Huh?

Here’s the deal: Korea has very strict laws about salicylic acid use in skincare (funny when you think Koreans put literally anything – from snail slime to jellyfish – into their products!). Brands get around them by using a different version of salicylic acid: betaine salicylate.

(FUN FACT: Paula’s Choice uses betaine salicylate in the BHA exfoliants it sells in Korea. 🙂 )

But is betaine salicylate as effective as salicylic acid?

We don’t know. The manufacturer swears it is – if you use double the amount! So, to get the results 2% salicylic acid gives you, you need to use 4% betaine salicylate.

FYI, some websites that sells Cosrx BHA Blackhead Power Liquid proudly boast that it has 4% BHA. This is to trick you into thinking that’s more powerful than Paula’s Choice and other exfoliants that use 2%. But if this study is true, that’s BS. It has more because you need to use more to get the same results. Don’t fall for it!

Related: Why Salicylic Acid Is The Key To Spot-Free Skin

What Else Do I Need To Know?

Not only Cosrx BHA Blackhead Power Liquid and Paula’s Choice Skin Perfecting 2% BHA Liquid have a different active ingredient. The rest of the formulas are different too!

Cosrx is more hydrating. It has hyaluronic acid, a moisture magnet that attracts and binds to the skin up to 1000 times its weight in water. Plus, a big dollop of niacinamide, a multitasker that hydrates skin, soothes irritations, reduces fine lines, fades away dark spots and treats acne. You name it, it does it!

Paula’s Choice is a little oilier. It has a big drop of methylpropanediol, another moisture magnet. But unlike hyaluronic acid, it makes your skin look a bit greasy (not the best look if your skin’s already oily). But it has green tea to soothe irritations and fight wrinkles.

Which Of The Two Should You Go For?

I’m a sciencey beauty blogger. I have to recommend you to go with Paula’s Choice simply because salicylic acid is tried and tested while studies on betaine salicylate are still lacking. *sighs*

And if salicylic acid is already working wonders for you, why rock the boat and switch things up? If the oily finish really bothers you, Paula’s Choice has plenty of other products with salicylic acid. You’ll find the right one for you.

But if your skin’s so sensitive it can’t tolerate salicylic acid, then betaine salicylate is well worth a try. 


Cosrx BHA Blackhead Power Liquid: £22.00 at Cult Beauty and Yes Style

Paula’s Choice Skin Perfecting 2% BHA Liquid: $29.00 at Paula’s Choice

Is Cosrx BHA Blackhead Power Liquid A Dupe For Paula’s Choice Skin Perfecting 2% BHA Liquid?

Nope. They have completely different ingredients! But Cosrx BHA Blackhead Power Liquid is a gentler version of Paula’s Choice Skin Perfecting 2% BHA Liquid. If you have sensitive skin, give it a try.


Have you tried Cosrx BHA Blackhead Power Liquid and Paula’s Choice Skin Perfecting 2% BHA Liquid and which one is your fave? Let me know in the comments below.

Cosrx BHA Blackhead Power Liquid Ingredients: Salix Alba (Willow) Bark Water, Butylene Glycol, Betaine Salicylate, Niacinamide, 1,2-Hexanediol, Arginine, Panthenol, Sodium Hyaluronate, Xanthan Gum, Ethyl Hexanediol

Paula’s Choice Skin Perfecting 2% BHA Liquid Ingredients: Water (Aqua), Methylpropanediol (hydration), Butylene Glycol (hydration), Salicylic Acid (beta hydroxy acid/exfoliant), Polysorbate 20 (stabilizer), Camellia Oleifera Leaf Extract (green tea/skin calming/antioxidant), Sodium Hydroxide (pH balancer), Tetrasodium EDTA (stabilizer)

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Alyssa May 14, 2018 - 5:12 pm

Great review! I actually wanted to mention though that the Paula’s Choice BHA sold in Korea no longer contains Betaine Salicylate. They reformulated it to contain .5% Salicylic Acid. This information isn’t anywhere that I could find on the new bottles (which simply reads Skin Perfecting BHA with Salicylic Acid) or the Korean website, but I called the Paula’s Choice Korean phone line and was given that information.

Gio May 19, 2018 - 1:03 pm

Alyssa, thanks for letting us know!

SmoothOperator May 17, 2018 - 3:11 am

Hi there! I have used Cosrx BHA and is amazing. My skin is oily with tendency to blackheads, also sensitivity to salicylic acid, so I tried this one and the effect was immediate; the pores became cleaner, but it was gentle and hydrating on my skin. I have tried different actives to clean my sun damaged/acne pron skin and nothing compares with the great effect it has; you can use retinol at night and BHA during the day. Has been using it for almost 2 years and the effect keeps going. Another advantage, the price! is almost a gift and the bottle lasts long.

Gio May 18, 2018 - 3:19 pm

Smoothoperator, thanks for sharing your experience. Glad to hear this is working so well for you.

Jane August 14, 2018 - 1:55 pm

I own both of these products, and find that I have to be very careful using the COSRX liquid because my skin often reacts badly to it (red, blotchy, irritated) – whereas my skin tolerates the Paula’s choice liquid very well. I’m not sure why this happens with the COSRX – I don’t have particularly sensitive skin, I tolerate retinol and other actives well. I wonder if there’s an ingredient I’m reacting to – but nothing stands out to me as a possible culprit on the ingredients list…it’s a mystery!

Gio August 16, 2018 - 1:37 pm

Jane, unfortunately these myths are common in skincare. You never know how your skin will react to something until you try it.

Jair elijah September 19, 2018 - 4:56 pm

Such a good post!
Paulas choice 2% BHA Liquid Exfoliant is my holy grail and works wonders for my skin. I studied salicylic acid and knee that the active ingredients where different. Still tried the cosrx one but soon realized that it just irritated my skin so bad.. PC for me

Gio September 26, 2018 - 7:47 pm

Jair, glad you’ve enjoyed the post. I know people who swear by PC and others who claim Cosrx works better for them. It’s great that we have the option so everyone can find something that works for them.

Natalie April 16, 2019 - 4:33 am

I’ve been using the Cosrx only because it’s easily accessible for me and about a third of the price here in Canada. I’m all about sciency skincare as well but this one is a winner for me! I use it after cleansing every or everyother evening before applying my humectant and moisturizer. LOVE it. My acne is healing.

Gio April 20, 2019 - 3:09 pm

Natalie, glad it’s working well for you. BHA is the best for acne.


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