How Glycolic Acid 5% Cream Works
Glycolic acid 5% cream works as an alpha-hydroxy acid (AHA) chemical peeling agent that breaks down the adhesions between skin cells (corneocytes) in the stratum corneum, promoting exfoliation of superficial skin layers and accelerating cell turnover. 1, 2
Primary Mechanism of Action
Chemical keratolysis: Glycolic acid disrupts the intercellular bonds (desmosomes) that hold dead skin cells together, allowing them to shed more easily from the skin surface 2, 3
pH-dependent activity: The mechanism is concentration and pH-dependent, with the nonionic (undissociated) form of glycolic acid being more biologically active than the anionic form 4
Penetration characteristics: As the smallest alpha-hydroxy acid molecule, glycolic acid penetrates the stratum corneum more effectively than larger AHAs, allowing it to reach deeper into the epidermis 5, 6
Secondary Effects on Skin Structure
Dermal remodeling: Beyond surface exfoliation, glycolic acid stimulates changes in papillary dermis connective tissue proteins, promoting collagen synthesis and improving skin texture 3, 5
Pigmentation reduction: The exfoliating action removes excess melanin-containing cells from the epidermis, helping to fade hyperpigmentation, lentigines, and melasma 3, 5
Antimicrobial properties: At appropriate pH levels (pH 3-4.5), glycolic acid exhibits antibacterial activity against Cutibacterium acnes by disrupting bacterial cell membranes, which contributes to its efficacy in acne treatment 4
Clinical Applications at 5% Concentration
Acne management: The American Academy of Dermatology recognizes glycolic acid peels (at higher concentrations of 20-70%) for treating acne vulgaris and acne scars, though 5% formulations provide gentler daily exfoliation 1
Photoaging and warts: The British Association of Dermatologists notes glycolic acid 5% acts as a well-tolerated peeling agent for conditions like facial plane warts, though evidence quality is limited 1
Home-use formulation: The 5% concentration is designed for daily home use rather than professional peeling, providing gradual exfoliation with lower irritation risk compared to higher concentrations 7, 2
Important Safety Considerations
Photosensitivity warning: The FDA mandates a sunburn alert on glycolic acid products, as AHAs increase skin sensitivity to UV radiation and sunburn risk; patients must use broad-spectrum sunscreen, wear protective clothing, and limit sun exposure during use and for one week after discontinuation 8, 7
Irritation profile: Common side effects include dryness, peeling, scaling, erythema, and burning sensation; glycolic acid generally causes more stinging than L(+) lactic acid at equivalent concentrations 7, 6
Contraindications for higher concentrations: While the 5% home-use concentration has minimal contraindications, professional glycolic acid peels (20-70%) should not be used within 6 months of isotretinoin therapy, or in patients with active infections, open wounds, active retinoid dermatitis, or history of abnormal scarring 1, 7
Optimal Use Strategy
Application timing: When combined with other active ingredients like tretinoin, the American Academy of Dermatology recommends applying glycolic acid 7% in the morning and tretinoin in the evening to optimize tolerance 7
Gradual introduction: Start with once-daily application and increase frequency as tolerated; reduce to every other day if excessive dryness or irritation occurs 7, 9
Avoid concurrent irritants: Do not combine with other keratolytic agents or photosensitizing products during the initial adjustment period 7