What Are AHA & BHA's in Skincare?

By Georgia Doherty

AHA & BHA's in Skincare

If you're looking to level up your skincare routine, chances are you've come across the terms AHA and BHA. These buzz-worthy ingredients are both types of exfoliants, but they work in different ways - and knowing the difference can help you choose the right one for your skin.

Let’s take a closer look.

What do AHA and BHA stand for?

  • AHA stands for Alpha Hydroxy Acid
  • BHA stands for Beta Hydroxy Acid

Both are chemical exfoliants (don’t let the word “chemical” scare you - it just means they exfoliate without needing rough physical scrubs), and both help to remove dead skin cells to reveal brighter, smoother skin.

But they target different layers of the skin - and different concerns.

What do AHAs do?

AHAs are water-soluble acids that work on the skin’s surface. They break down the bonds between dead skin cells so they can gently shed, leaving your skin feeling softer and looking more even.

Common AHAs:

  • Glycolic acid – the most potent AHA, great for brightening and smoothing
  • Lactic acid – more gentle and hydrating, ideal for dry or sensitive skin
  • Mandelic acid – larger molecule, good for sensitive and acne-prone skin

AHAs are great for:

  • Dullness
  • Uneven texture
  • Fine lines
  • Pigmentation
  • Dry or flaky skin

What do BHAs do?

BHAs are oil-soluble, which means they can penetrate deeper into your pores, dissolving excess sebum and dead skin cells. This makes them especially helpful for oily or acne-prone skin.

The most common BHA:

  • Salicylic acid – helps unclog pores, reduce inflammation, and fight breakouts

BHAs are great for:

  • Blackheads and whiteheads
  • Acne and breakouts
  • Enlarged or clogged pores
  • Oily or combination skin

Can I use both AHA and BHA together?

Yes - but with caution. Combining both can offer a more thorough exfoliation, targeting surface texture and deeper congestion. However, using too much or too often can lead to irritation, dryness, or sensitivity.

If you're new to exfoliating acids:

  • Start slow (1–2 times per week)
  • Use gentle formulations
  • Always follow with moisturiser and SPF

How to use AHAs and BHAs safely

  1. Patch test first: especially if you have sensitive skin.
  2. Don’t overdo it: exfoliating too often can damage your skin barrier.
  3. Use at night: acids can make your skin more sensitive to sunlight.
  4. Wear SPF daily: AHAs and BHAs increase your skin’s sun sensitivity.
  5. Listen to your skin: if you feel stinging, flaking, or redness, give your skin a break.

AHAs and BHAs are powerful exfoliators that can transform your skin - helping with breakouts, uneven tone, dullness, and texture. Whether you’re looking for a glow boost or a way to clear congestion, understanding how these acids work can help you choose the right one (or combination) for your skin goals.

Frequently Asked Questions

  • Yes - but it’s important to choose gentle formulas and start slow. Lactic acid (AHA) and mandelic acid are typically better tolerated by sensitive skin than glycolic or salicylic acid. Always patch test first and follow with a hydrating moisturiser.

  • Start with 1–2 times per week and see how your skin responds. If your skin tolerates it well, you can gradually increase to every other day or as recommended on the product. Over-exfoliation can lead to redness, sensitivity, and breakouts.

  • Yes, many products combine both - or you can layer them thoughtfully - but this can be intense, especially for beginners. If you’re combining them, do so no more than 1–2 times per week, and avoid using other strong actives (like retinol) on the same night.

  • Nighttime is best, as your skin is more vulnerable to sun sensitivity after exfoliating. If you do use them during the day, be sure to follow up with a broad-spectrum SPF 30 or higher.

  • Chemical exfoliants like AHAs and BHAs are exfoliators - so you can skip the scrubs. There’s no need for physical exfoliation on top, which can overdo it and irritate the skin.

  • It’s best to use them on alternate nights unless your skin is very tolerant and you're under professional guidance. Using both together can increase the risk of dryness, irritation, or a compromised skin barrier.

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