What These Acids Really Do for Your Skin
When I was preparing Sephora training for Laneige Water Bank Aqua Facial,
I found myself revisiting something we hear all the time in skincare — acids.
AHA, BHA, PHA.
They sound technical, sometimes even intimidating.
But once you understand how they work and who they’re actually for, they become far less scary — and far more useful.
This post is a simple breakdown of PHA, BHA, and AHA, based on both formulation logic and real-life skin behaviour.
## What You’ll Learn in This Post
- What AHA, BHA and PHA are
- How each acid works for your skin
- Which acid suits which skin type
AHA (Alpha Hydroxy Acid) : Surface exfoliation & glow
AHA is a water-soluble acid that works mainly on the surface of the skin.
What it does
- Removes dead skin cells from the outer layer
- Improves dullness and uneven texture
- Helps makeup sit better
- Encourages a brighter, smoother look
Common AHAs
- Glycolic acid
- Lactic acid
Best for
- Normal to dry skin
- Dull or uneven skin tone
- Skin that feels rough or looks tired
Note:
AHAs can feel strong, especially if your skin barrier is compromised.
They work best when balanced with hydration — not used aggressively.
BHA (Beta Hydroxy Acid) Pore care & oil balance
BHA is an oil-soluble acid, which means it can go inside pores, not just sit on the surface.
What it does
- Clears excess sebum inside pores
- Helps reduce blackheads and congestion
- Calms inflammation related to breakouts
Common BHA
- Salicylic acid
Best for
- Oily or combination skin
- Congested pores
- Occasional breakouts
Note:
Because it penetrates deeper, BHA can sometimes feel drying if overused — especially in hot, dry climates.
PHA (Poly Hydroxy Acid) Gentle exfoliation & barrier-friendly care
PHA is often described as the gentlest form of chemical exfoliation.
What makes it different
- Larger molecule size → slower penetration
- Less irritation compared to AHA/BHA
- Attracts and holds moisture
What it does
- Mild exfoliation without stressing the skin
- Supports hydration
- Helps maintain skin barrier comfort
Best for
- Sensitive skin
- Dehydrated skin
- Skin that reacts easily
- First-time acid users
This is why PHA is often chosen in hydration-focused formulas, like Laneige Aqua Facial.
AHA vs BHA vs PHA — Quick Comparison
| Acid | Works Where | Main Benefit | Best For |
|---|---|---|---|
| AHA | Skin surface | Brightening & smoothing | Dry, dull skin |
| BHA | Inside pores | Oil & congestion control | Oily, acne-prone |
| PHA | Surface (gentle) | Mild exfoliation + hydration | Sensitive, dehydrated |
Why Laneige Aqua Facial Uses This Acid Balance
Instead of relying on strong exfoliation, Laneige Aqua Facial uses acids in a skin-friendly way.
The focus isn’t:
“Let’s peel the skin.”
It’s more:
“Let’s gently smooth, so hydration can actually absorb better.”
- PHA helps refine texture without irritation
- Mild exfoliation supports glow
- Hydration remains the hero, not the afterthought
This makes it suitable even for:
- Dehydrated skin
- Sensitivity-prone skin
- Skin exposed to heat, air-con, or strong UV (very Australia-coded)
Acids don’t have to mean irritation.
Used correctly, they can actually support hydration, clarity, and skin comfort.
Understanding which acid does what — and why it’s used — makes all the difference between stressing your skin and helping it recover.
If you’ve ever felt confused standing in front of an ingredient list, this is your sign: it’s not about stronger — it’s about choosing what works best for your skin.
Want help choosing the right acid for your routine? Comment below or check out our other ingredient guides
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