Chemical Exfoliants: AHAs vs BHAs
Chemical exfoliants are powerful tools for achieving smoother, clearer skin. Understanding the difference between AHAs and BHAs helps you choose the right exfoliant for your specific concerns.
Alpha Hydroxy Acids (AHAs) - Water-Soluble, Surface Action
AHAs work by breaking down the "glue" (desmosomes) holding dead skin cells together, promoting even resurfacing.
| AHA Type | Source | Molecular Size | Strength | Best For |
|---|---|---|---|---|
| Glycolic Acid | Sugarcane | Smallest | Strongest | All skin types, most effective penetration |
| Lactic Acid | Milk | Medium | Gentle | Sensitive skin, hydration + exfoliation |
| Mandelic Acid | Almonds | Largest | Mildest | Very sensitive skin, rosacea-prone |
| Citric Acid | Citrus | Small | Moderate | Brightening, antioxidant properties |
Beta Hydroxy Acids (BHAs) - Oil-Soluble, Pore-Penetrating
The key differentiator: BHAs are lipophilic, allowing them to penetrate through sebum into pores.
Salicylic Acid
Most common BHA, derived from willow bark. Anti-inflammatory properties make it ideal for acne.
Betaine Salicylate
Gentler alternative; 4% betaine ≈ 2% salicylic acid
Dermatologist Agreement: 93.6% for acne (salicylic acid)Key Differences
| Factor | AHAs | BHAs |
|---|---|---|
| Solubility | Water-soluble | Oil-soluble |
| Penetration | Surface | Deep into pores |
| Best for | Dullness, hyperpigmentation, fine lines | Blackheads, whiteheads, oily skin |
| Sun sensitivity | Higher increase | Lower increase |
| Ideal skin type | Dry, sun-damaged, aging | Oily, acne-prone |
How to Use Chemical Exfoliants
Starting Protocol
Can You Combine AHAs and BHAs?
Yes! You can:
Signs of Over-Exfoliation
If you experience these, stop exfoliating and focus on barrier repair for 2-4 weeks.
The Bottom Line
AHAs and BHAs serve different purposes. AHAs excel at surface renewal and brightness, while BHAs dive deep to clear pores. Most people can benefit from using both strategically.
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