Skincare Acid Guide: What Are AHA and BHA?

AHA and BHA, commonly known as chemical exfoliants, are among the most effective active ingredients for removing dead skin cells without physical abrasion.

Unlike scrubs, they work by dissolving the bonds between dead skin cells, allowing controlled and even skin renewal.

How Do AHA and BHA Work?

Dead skin accumulation can lead to:

• Dullness
• Rough texture
• Clogged pores
• Uneven tone

Acids break down the bonds holding these cells together, triggering controlled exfoliation and renewal.

1. AHA (Alpha Hydroxy Acids)

AHAs are water-soluble acids that work on the skin’s surface.

Key Benefits:

• Surface exfoliation
• Brightening effect
• Smoothing fine lines
• Improving skin tone

Best For:

• Dry skin
• Normal skin
• Dull or uneven skin
• Aging skin

Common AHAs:

Glycolic Acid

• Smallest molecule
• Strongest AHA
• Deep surface penetration

Lactic Acid

• Gentle exfoliation
• Hydrating properties
• Suitable for dry skin

Mandelic Acid

• Slow absorption
• Best for sensitive skin

2. BHA (Beta Hydroxy Acids)

BHAs are oil-soluble acids, making them unique in their ability to penetrate pores.

Key Benefits:

• Deep pore cleansing
• Blackhead reduction
• Oil control
• Anti-inflammatory effects

Best For:

• Oily skin
• Combination skin
• Acne-prone skin

Main BHA:

Salicylic Acid

• Penetrates inside pores
• Dissolves excess sebum
• Helps reduce acne formation

AHA vs BHA Differences

Safe Usage Strategy

Acids are powerful actives and must be introduced carefully.

1. Start Slowly

• Begin with 1 night per week
• Monitor skin response
• Increase gradually to 2–3 nights weekly

2. Night-Time Only

Acids:

• Increase sun sensitivity
• Can cause pigmentation issues if misused

3. Combination Rules

AHA + BHA same night?

• Not recommended for most skin types
• May overload the skin barrier

Better approach:

• Alternating usage
• Skin cycling method

4. Example Skin Cycling

• Night 1: AHA
• Night 2: BHA
• Night 3–4: Recovery (hydration only)

Post-Acid Barrier Support

After acids, the skin must be supported:

• Ceramides → barrier repair
• Panthenol → soothing
• Hyaluronic acid → hydration
• Niacinamide → balancing

Sun Protection (MANDATORY)

Acid-treated skin is:

• More UV-sensitive
• More prone to pigmentation

Minimum requirement:

• SPF 30+ daily
• Consistent morning application
• Reapplication when needed

Sensation Guide

Normal:

• Mild tingling
• Slight warmth

Warning signs:

• Persistent burning
• Redness that does not fade
• Excessive peeling

In such cases, discontinue use and focus on barrier repair.

Conclusion

AHA and BHA are highly effective exfoliating acids when used correctly.

• AHA = surface glow and texture
• BHA = pore cleansing and oil control

Correct acid choice = correct skin outcome