First Impression: COSRX Low pH BHA Overnight Mask

First Impression: COSRX Low pH BHA Overnight Mask

Happy Skincare Sunday Dewy fam!

Jane here, and today I wanted to share my quick first impression of the new COSRX Low pH BHA Overnight Mask.

We were lucky enough to be selected by Cupidrop to be part of their 6th generation of Beautiful Pioneers. Thank you to Jenny and Cupidrop for providing this product, as well as the COSRX Low pH PHA Barrier Mist as an added bonus! We are so grateful for the opportunity to try them!

I was particularly interested in trying this product because COSRX is one of my favorite K-Beauty brands and I’ve yet to meet a product from them that I didn't like. I have oily/combination, acne-prone skin so this BHA mask sounded right up my alley. Read on for my first impressions on this overnight mask. 

About the Product

In true COSRX fashion, the Low pH BHA Overnight Mask has quite a long descriptive name (which I’ve learned to appreciate). It’s a moisturizing sleeping mask that contains 0.9% BHA to reveal smoother skin and a brighter complexion the next day.



Centella Asiatica Leaf Water, Butylene Glycol, Helianthus Annus (Sunflower) Seed Oil, Glycerin, Betaine, Panthenol, Cetearyl Alcohol, Dimethicone, Elaeis Guineensis (Palm) Oil, Elaeis Guineensis (Palm) Kernel Oil, Beeswax, Gluconolactone, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Cetearyl Olivate, Sorbitan Olivate, Caprylic/Capric Triglyceride, 1,2-Hexanediol, Betaine Salicylate, Ethylhexylglycerin, Lactic Acid, Water, Niacinamide, Xanthan Gum, Sodium Hydroxide, Ethyl Hexanediol, Melaleuca Alternifolia (Tea Tree) Leaf Oil

The key ingredient in this mask is 0.9% BHA, but it contains many other star ingredients to boot. The 0.9% BHA comes in the form of betaine salicylate. BHAs are chemical exfoliants which penetrate below the surface of the skin and work to dissolve excess oil in your pores with their oil-soluble nature. The mask also contains lactic acid, an AHA that works at the surface level, so you get the best of both exfoliating worlds.

Centella asiatica leaf water - which is totally having a moment right now - is listed first on the ingredients list and is known for its high antioxidant and anti-inflammatory properties. Niacinamide works to brighten skin and lastly, the formulation contains tea tree leaf oil which is great for oily, acne-prone skin. One downside is the presence of dimethicone, which is a silicone, that acts as an occlusive to seal in moisture.

According to COSDNA there are a few irritants and acne triggers: butylene glycol (1), dimethicone (1), cetearyl alcohol (2), and besswax (0-2).


The mask smells like salicylic acid and tea tree, it has a strong herbal smell. Like I’ve mentioned before, I enjoy the smell of tea tree, so it isn't an issue for me. The mask scent does not linger after application.



It comes in a sleek, hygienic tube which I love. There was a silver seal over the opening of the tube which I peeled off, however, I believe you can use the top of the cap to poke a hole into the seal for a smaller opening. I admit the tube opening is a bit hard to control without squeezing out too much.


I was surprised by the texture - it’s a balmy texture that is somewhere between a thick ointment and a cream. I believe the dimethicone makes it go on a bit smoother but it is still takes a moment to spread it all over. Despite the texture it absorbs quite easily and does not feel heavy or greasy.



This is a sleeping mask so it should be applied as the last step of your PM routine, then washed off the following morning. If the mask is applied during the daytime, sunscreen must be applied as BHA and AHA exfoliants cause increased sensitivity to UV rays.

Overall Thoughts

I’ve used this overnight mask a handful of times since I received it last Friday. In this short period of time I haven’t noticed anything too drastic, but I do wake up with softer skin. It seems to be working well to smooth out the rough texture I’ve had lately since I'm recovering from breakouts at the moment. The mask is different from the other overnight masks in my collection and I love that it has BHA to help fight acne while I sleep. It soothes my skin and doesn’t cause any irritation or clogged pores so that’s a huge plus for me! Now, it isn’t the most hydrating sleeping mask, but I like it so far and will continue to use it and report back if I see more significant results. (For a more hydrating/brightening mask, I would recommend COSRX's Ultimate Nourishing Rice Overnight Spa Mask instead.)

Where to Purchase

You can purchase this mask at Cupidrop for $21. Receive 15% off your order over $30 with code “NICESKIN” through April 30, 2018.

Would you give this overnight mask a try? Let us know what you think in the comments!

Stay Dewy,


*Disclaimer: This product was provided by Cupidrop for testing purposes. All opinions are honest and my own.

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