A Breakdown of Skincare Acids (And How to Stop Mixing Them Incorrectly)

Let’s talk about acids because there are many types of acids and they all do different things, but figuring out which acids you can use, should use, and absolutely should not use together can be a struggle.

Layering skincare can feel like chemistry class, but don’t worry! I did really well in school, so you can look at my notes. 😉

Acids are powerful and can completely transform your skin—but also completely irritate it if you mix and layer certain acids in your routine. So I wanted to break down the main types of acids in a simple way to explain what they do, why people love them, and how to use them safely.

Alpha Hydroxy Acids (AHAs): The Surface Smoothers

These acids work by weakening the bonds between dead skin cells, allowing them to slough off more easily.

• Lactic Acid: This is the gentle one—the friendliest AHA.
  It exfoliates, moisturizes, and brightens without being too intense. If your skin tends to get irritated, this is a great place to start.
• Glycolic Acid: Glycolic is the overachiever of the AHA family.
  It penetrates the deepest, exfoliates the most, and brightens the fastest. Amazing for texture and dullness, but it can be too strong if you’re using other actives like tretinoin.
  I recommend the Alastin Polish if this sounds like what you need.

Beta Hydroxy Acids (BHAs): The Pore Cleaners

BHAs are oil-soluble, so they work inside the pores, making them perfect for acne, congestion, and blackheads.

• Salicylic Acid: If your pores feel clogged, this is your go-to product.
  It exfoliates, brightens, fights acne, and is amazing for oily skin or stubborn blackheads. It’s also a must-have ingredient in most acne routines.
  Dr. Monica’s Brightening Exfoliating Cleanser has both glycolic and salicylic acid, if you feel you need both in your routine
• Hyaluronic Acid: The Hydrator (Not an Exfoliant)
  Let’s clear up the biggest myth: hyaluronic acid is not an exfoliating acid.
  It’s a humectant—meaning it pulls water into the skin to hydrate and plump.
  If you use hyaluronic acid, layer a moisturizer on top to lock in your moisture and hydration. 
  This Isdin HA was my first favorite, but I’ve also been loving this Hydrinity product recently.
• Azelaic Acid: The Calm Problem-Solver: One of the most underrated ingredients.
  It brightens, lightly exfoliates, fights acne, and reduces redness. If you have sensitive skin, rosacea, or melasma, azelaic acid is a superstar.
• Ascorbic Acid (Vitamin C): The Brightening Antioxidant
  Vitamin C is known for brightening, fighting free radicals, evening out skin tone, and supporting collagen production. 
  Let’s talk more about Vitamin C here.
• Tranexamic Acid: The Pigmentation Corrector (Not an Exfoliant)
  Tranexamic acid is for stubborn pigment. It doesn’t exfoliate but works by calming the pathways in the skin that trigger pigment production. It helps with: melasma, sunspots, dark patches, post-acne marks, overall uneven tone.
  
  What I love about tranexamic acid is that it’s gentle, works well with other brighteners like niacinamide and vitamin C, and is safe for most skin types, even sensitive ones. If you’ve ever felt like your pigmentation is “deeper” or easily triggered by heat, sun, or hormones—tranexamic acid will be your friend.
  
  I really like the Melaclear Advance from Isdin, but Raella loves the SkinBetter Science Even Intensive. 

Acids can be intimidating, but they don’t have to be. Once you understand what each one does, it becomes so much easier to pick the right one for your routine, and just as importantly, avoid using the wrong combinations.

Here’s a little cheat sheet:

If your skin is feeling dull → try lactic or glycolic.
If your pores are clogged → salicylic is your friend.
If your skin is sensitive or red → azelaic is a lifesaver.
If your skin is dehydrated → hyaluronic acid is a must.
If you want brightness and collagen → bring in vitamin C.
If you struggle with stubborn pigment → tranexamic acid. 

If this still feels overwhelming, you can book a free consultation with our Aesthetic Concierge Raella and have her come up with a plan for you. 

Have questions about which one might be best for you? Feel free to email me anytime at mmahoney@drmonicascheel.com or call my direct line at (808) 666-2078. I love talking about skincare, and I’d be happy to help. 

Mahalo for reading, and here’s to healthy, glowing skin!