Glycolic Acid

INCI: Glycolic Acid
Category: Alpha Hydroxy Acid (AHA) / Chemical Exfoliant
Used in: Toners, serums, peels, cleansers, moisturisers
Typical Usage Level (Topical): 1-12% (leave-on); up to 20–70% (professional peels)

What This Ingredient Does

Glycolic acid is the smallest AHA by molecular weight, which allows it to penetrate the skin surface more readily than other acids. It works by loosening the bonds between dead skin cells (corneodesmosomes) at the outermost layer, allowing them to shed more efficiently. This speeds up cell turnover, clears surface congestion, and progressively improves skin texture and tone with consistent use. At higher concentrations, it also stimulates fibroblast activity, supporting collagen over time.

Works well alongside Niacinamide (to manage post-exfoliation sensitivity) and Hyaluronic Acid (to restore hydration post-peel).

Key Benefits

• Visibly improves uneven skin texture and rough patches
• Reduces the appearance of post-inflammatory hyperpigmentation (PIH) over time
• Unclogs pores and reduces surface congestion
• Supports collagen stimulation at higher concentrations
• Enhances absorption of actives applied after exfoliation

Who It's Best For

• Oily, congested, or acne-prone skin
• Those targeting dullness, uneven texture, or early signs of photoageing
• Not recommended for reactive, compromised, or eczema-prone skin without medical guidance
• Darker skin tones should start low (5%) and patch test; risk of PIH with overuse

Clinical Note by Dr. Su

Glycolic acid is effective but needs respect — the small molecule size means it acts fast, which increases the chance of irritation if overused. Start with a low concentration, use at night, and always follow with SPF the next morning. If your skin stings for more than 30 seconds, rinse it off.

References

Sharad J. (2013). Glycolic acid peel therapy – a current review. Clinical, Cosmetic and Investigational Dermatology. PMC3875240