Good Active Ingredient GHS Classified Dermal Penetration

Glycolic Acid

INCI: GLYCOLIC ACID

CAS Number
79-14-1
Function
Smallest AHA (MW 76 Da) enabling the deepest epidermal penetration of the AHA class. At <25% produces superficial exfoliation; 25–50% causes keratinocyte discontinuity; 50–75% causes epidermolysis. Disrupts desmosomal cohesion via calcium ion chelation, thinning the stratum corneum and promoting cell turnover. Efficacy governed by free (undissociated) acid concentration per Henderson-Hasselbalch: at pH 3.5 (~68% free acid) vs pH 4.5 (~18% free acid). Also used as pH adjuster.
Safety Rating
GOOD

Regulatory Status

🇪🇺 EU Status restricted
EU Max Conc. 10% at pH ≥3.5 (twice-daily leave-on); professional peel concentrations up to 50–75% under controlled conditions only
🇺🇸 US Status permitted
US Notes CIR (1998, reaffirmed 2013): safe ≤10% at pH ≥3.5 for consumer cosmetics; ≤30% at pH ≥3.0 for professional use. FDA endorses CIR guidance; no binding statutory limit but references CIR in guidance. FDA-sponsored studies confirm up to 18% increased UV sensitivity persisting one week post-discontinuation; SPF labelling strongly advised. Optimal pH range 3.5–4.5.

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
high
Sensitization
low

Calculate MoS for your specific formulation with the MoS Calculator.

GHS Hazard Classification

Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.

Short-term Exposure Effects
The substance is corrosive to the skin and eyes. The substance is irritating to the respiratory tract. Corrosive on ingestion. The substance may cause effects on the kidneys. This may result in kidney failure.
Long-term Exposure Effects
Repeated or prolonged contact with skin may cause dermatitis.
Routes of Exposure
The substance can be absorbed into the body by inhalation and by ingestion.

Dermal Penetration Profile

Skin absorption and penetration characteristics of Glycolic Acid, relevant to systemic exposure and MoS calculations.

Absorption %
15-25%
Penetration Level
epidermis
Penetration Depth
epidermis
Molecular Weight
76.1 Da
Log P
-1.11
Systemic Absorption
yes
Topical Bioavailability
10-20%
Safety Margin Factor
moderate
Vehicle Dependent
Yes — absorption varies by formulation

Source: SCCS/1516/13, CIR

Expert Verdict

Glycolic acid is the gold-standard AHA and most evidence-supported chemical exfoliant. Effective for post-inflammatory hyperpigmentation, anti-aging, and acne, but safety and efficacy both hinge on free acid value—total percentage alone is meaningless without pH context. EU SCCS guidance (10% pH ≥3.5) is the operative ceiling for consumer products. Photosensitivity is a documented risk: daily SPF messaging is essential. Greater caution warranted for Fitzpatrick IV–VI due to concurrent lightening of surrounding normal skin at peel concentrations.

⚠️
Concern Level: Low

Regulatory Flags

photosensitizing ph-critical concentration-dependent-safety barrier-disrupting eu-restricted piH-risk-dark-skin-tones

Frequently Asked Questions

Is Glycolic Acid safe in cosmetics?

Glycolic acid is the gold-standard AHA and most evidence-supported chemical exfoliant. Effective for post-inflammatory hyperpigmentation, anti-aging, and acne, but safety and efficacy both hinge on free acid value—total percentage alone is meaningless without pH context. EU SCCS guidance (10% pH ≥3.5) is the operative ceiling for consumer products. Photosensitivity is a documented risk: daily SPF messaging is essential. Greater caution warranted for Fitzpatrick IV–VI due to concurrent lightening of surrounding normal skin at peel concentrations. The EU classifies Glycolic Acid as "restricted". Safety rating: GOOD.

Is Glycolic Acid allowed in the EU?

Glycolic Acid EU regulatory status: restricted. Maximum allowed concentration: 10% at pH ≥3.5 (twice-daily leave-on); professional peel concentrations up to 50–75% under controlled conditions only. This is based on EU Regulation 1223/2009 and its amendments.

What does Glycolic Acid do in cosmetics?

Glycolic Acid functions as: Smallest AHA (MW 76 Da) enabling the deepest epidermal penetration of the AHA class. At <25% produces superficial exfoliation; 25–50% causes keratinocyte discontinuity; 50–75% causes epidermolysis. Disrupts desmosomal cohesion via calcium ion chelation, thinning the stratum corneum and promoting cell turnover. Efficacy governed by free (undissociated) acid concentration per Henderson-Hasselbalch: at pH 3.5 (~68% free acid) vs pH 4.5 (~18% free acid). Also used as pH adjuster.. It is classified as a Active Ingredient in our database. CAS number: 79-14-1.

What is the Margin of Safety for Glycolic Acid?

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

Compliance Tools

Check Glycolic Acid compliance across multiple jurisdictions:

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Ingredient Decoder
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82 Allergen Checker
Check for EU declarable fragrance allergens
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Substance Compliance
Check compliance across 55 jurisdictions
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
 ⚗️
Heavy Metal Limits
Compare limits across jurisdictions

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