Salicylic Acid (BHA): A Powerful Keratolytic & Anti-Acne Agent

Technical Introduction

Salicylic Acid is a beta hydroxy acid (BHA) and a derivative of salicin, originally extracted from willow bark. Unlike alpha hydroxy acids (AHAs), which are water-soluble, salicylic acid is oil-soluble, allowing it to penetrate deep into pores and dissolve excess sebum.

This unique property makes it highly effective in acne treatment, exfoliation, and dandruff control. It also has anti-inflammatory and keratolytic effects, making it widely used in both dermatology and cosmetic formulations.

• Chemical Name: 2-hydroxybenzoic acid

• Molecular Formula: C₇H₆O₃

• Molecular Weight: 138.12 g/mol

• CAS Number: 69-72-7

• Appearance: White crystalline powder

• Odor: Slight phenolic odor

• Solubility: Slightly soluble in water, highly soluble in ethanol, acetone, and oils

• pKa: ~2.97 (acidic nature important in formulation)

Applications

1. Dermatology & Skincare

• Acne treatment → Penetrates pores to dissolve sebum and unclog blackheads/whiteheads.

• Exfoliation & peels → Removes dead skin cells, improves cell turnover.

• Oil control → Regulates sebum, ideal for oily and acne-prone skin.

• Anti-inflammatory creams → Reduces redness and irritation from acne.

• Wart & callus treatment → Softens keratin for easier removal.

• Anti-dandruff shampoos → Helps remove flakes and excess scalp buildup.

2. Pharmaceuticals

• Used in topical medicines for psoriasis, keratosis, eczema, and hyperkeratotic conditions.

• Often formulated in medicated patches, ointments, and gels.

3. Cosmetics & Personal Care

• Facial cleansers, toners, serums (0.5–2% typical concentration).

• Peeling solutions (up to 20–30% for professional use).

• Hair care products for scalp exfoliation.

✅ Advantages

• Deep pore penetration (oil-soluble, unlike AHAs).

• Anti-inflammatory (reduces redness and swelling in acne).

• Exfoliating & keratolytic (smooths skin texture, brightens dull skin).

• Sebum regulation (ideal for oily skin).

• Clinically proven effectiveness for acne management.

⚙️ Technical Specifications (Typical Cosmetic/Pharma Grade)

⚠️ Safety & Regulations

• Topical Use (Cosmetics):

  • EU, US FDA, and ASEAN allow up to 2% in cosmetic leave-on products and 3% in rinse-off (except hair products, up to 3%).

  • Higher concentrations (20–30%) used only by dermatologists for chemical peels.

• Oral Use: Not recommended (toxic in high doses).

• Side Effects:

  • Can cause dryness, peeling, and irritation at high concentrations.

  • Not suitable for people allergic to aspirin (salicylates).

• Pregnancy & Children:

  • Avoid high concentrations during pregnancy.

  • Only low topical concentrations (<2%) recommended for teens/adolescents under medical guidance.

❓ FAQ

Q1: What’s the difference between Salicylic Acid (BHA) and AHAs (like Glycolic Acid)?
AHAs are water-soluble, targeting surface exfoliation. BHAs (salicylic acid) are oil-soluble, penetrating pores to clear sebum and acne.

Q2: Can Salicylic Acid be used daily?
Yes, in low concentrations (0.5–2%), it can be used daily in cleansers and serums. Higher concentrations should only be used under dermatological supervision.

Q3: How long before acne improves with salicylic acid?
Results typically appear after 2–4 weeks of consistent use.

Q4: Can Salicylic Acid be combined with retinol or benzoyl peroxide?
It can, but may increase irritation. It’s better to alternate (e.g., salicylic in the morning, retinol at night).

Q5: Is Salicylic Acid suitable for sensitive skin?
It may cause irritation in sensitive or dry skin types. A gentle formulation (low pH, encapsulated) is recommended.