If you’ve ever stared at your skincare shelf wondering whether you should reach for AHA or BHA, you’re not alone. COSRX makes two cult-favorite exfoliants,  the AHA 7 Whitehead Power Liquid and the BHA Blackhead Power Liquid, and both have legions of fans. But what’s the difference? And more importantly, which one is right for your skin?

Let’s break it down.

AHA vs. BHA: The Basics

• AHA (Alpha Hydroxy Acid): Water-soluble, works on the surface of the skin. Best for dullness, rough texture, and whiteheads.

• BHA (Beta Hydroxy Acid): Oil-soluble, penetrates deep into pores. Best for blackheads, acne, and excess sebum.

Think of it like this:

• AHA = sweeping the surface clean.

• BHA = unclogging what’s inside the pores.

COSRX AHA 7 Whitehead Power Liquid

• Main Ingredient: 7% Glycolic Acid (AHA)

• Best for: Whiteheads, uneven skin tone, rough patches, post-acne marks.

• How it works: Gently dissolves dead skin cells on the surface, revealing smoother, brighter skin underneath.

• Routine placement: After cleansing and toner, before serums/essence.

• How to use:

  1. Start 2–3 times a week.

  2. Apply with a cotton pad or your hands.

  3. Follow with hydrating products (snail mucin is perfect here).

  4. Always use sunscreen during the day.

Tip: If your main struggle is dullness or little bumps (whiteheads), this is your pick.

COSRX BHA Blackhead Power Liquid

• Main Ingredient: 4% Betaine Salicylate (gentler form of salicylic acid)

• Best for: Blackheads, clogged pores, oily or acne-prone skin.

• How it works: Travels into the pores to dissolve sebum and dead skin buildup, helping to prevent breakouts.

• Routine placement: After cleansing and toner, before serums/essence.

• How to use:

  1. Start 2–3 times a week.

  2. Apply evenly over congested areas (like nose, chin, T-zone).

  3. Let it absorb fully before layering the rest of your routine.

  4. Sunscreen is non-negotiable.

Tip: If you’re constantly battling blackheads or breakouts, BHA is the better choice.

Can You Use AHA and BHA Together?

Yes, but carefully. Both are exfoliants, so overdoing it can irritate. Here’s how to layer:

• Option 1: Alternate days. Use AHA one night, BHA the next.

• Option 2: Spot treat. Apply BHA only on clogged areas (nose/chin) and AHA on the rest of the face.

• Option 3: Weekly double-exfoliation. Once your skin is used to both, you can layer AHA first, then BHA (wait 20 mins in between), but no more than once a week.

Pairing with calming products like COSRX Snail Mucin Essence or Hydrium Moisture Power Enriched Cream keeps your barrier strong.

Which One Do You Need?

Choose AHA 7 Whitehead Power Liquid if:
✔ Your skin looks dull or textured
✔ You struggle with whiteheads or post-acne marks
✔ You want smoother, brighter skin

Choose BHA Blackhead Power Liquid if:
✔ You have oily or acne-prone skin
✔ You deal with blackheads or frequent breakouts
✔ You want clear, refined pores

Final Thoughts

Both the COSRX AHA 7 Whitehead Power Liquid and the COSRX BHA Blackhead Power Liquid are gentle yet effective ways to upgrade your routine. If your main concern is texture and brightness, go AHA. If it’s clogged pores and acne, go BHA. And if you’re a skincare enthusiast? You might find both earn a permanent spot on your shelf.

The golden rule: start slow, listen to your skin, and never skip SPF.