Good Active Ingredient Dermal Penetration

Mandelic Acid

INCI: MANDELIC ACID

CAS Number
90-64-2
Function
AHA exfoliant with highest MW among common AHAs (152 Da). Slower, more even skin penetration produces significantly less irritation than glycolic or lactic acid. Antibacterial activity against acne-causing organisms. Exfoliates without the aggressive brightening that can trigger rebound hyperpigmentation in darker skin tones. Key component of triple-acid peels (mandelic + salicylic + citric acid) validated in Fitzpatrick IV–V patients for acne and PIH treatment.
Safety Rating
GOOD

Regulatory Status

🇪🇺 EU Status permitted
🇺🇸 US Status permitted
US Notes Permitted cosmetic ingredient under FD&C Act. Not GRAS classified for OTC drug use. FDA 2005 AHA labeling guidance applies: products must include sun protection advisory (daily SPF use recommended). CIR 1998 report (reaffirmed 2017) evaluated glycolic and lactic acids but not mandelic acid specifically; comparable AHA safety conditions suggested (≤10% consumer, pH ≥3.5, sun protection). Not subject to any FDA concentration restriction as a cosmetic.

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

Safety Data

Margin of Safety (MoS)
not established
Dermal Absorption
moderate
Sensitization
none

Calculate MoS for your specific formulation with the MoS Calculator.

Dermal Penetration Profile

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

Absorption %
8-12%
Penetration Level
stratum-corneum
Penetration Depth
stratum corneum/epidermis
Molecular Weight
152.1 Da
Log P
0.59
Systemic Absorption
minimal
Topical Bioavailability
5-10%
Safety Margin Factor
low
Vehicle Dependent
Yes — absorption varies by formulation

Source: Dermatol Ther 2013

Expert Verdict

Mandelic Acid (CAS 90-64-2) is an alpha-hydroxy acid permitted without restriction under EU Regulation (EC) No. 1223/2009 and US FD&C Act. Non-irritating to skin, LLNA negative, non-mutagenic. Key concerns: H318 serious eye damage classification; AHA-class photosensitivity (~18% increase in UV-induced skin sensitivity). Data gaps exist for NOAEL from repeated dose studies and reproductive/developmental toxicity.

⚠️
Concern Level: Moderate

Regulatory Flags

eu-unrestricted no-cir-review no-sccs-opinion phototoxic

Frequently Asked Questions

Is Mandelic Acid safe in cosmetics?

Mandelic Acid (CAS 90-64-2) is an alpha-hydroxy acid permitted without restriction under EU Regulation (EC) No. 1223/2009 and US FD&C Act. Non-irritating to skin, LLNA negative, non-mutagenic. Key concerns: H318 serious eye damage classification; AHA-class photosensitivity (~18% increase in UV-induced skin sensitivity). Data gaps exist for NOAEL from repeated dose studies and reproductive/developmental toxicity. The EU classifies Mandelic Acid as "permitted". Safety rating: GOOD.

Is Mandelic Acid allowed in the EU?

Mandelic Acid EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

What does Mandelic Acid do in cosmetics?

Mandelic Acid functions as: AHA exfoliant with highest MW among common AHAs (152 Da). Slower, more even skin penetration produces significantly less irritation than glycolic or lactic acid. Antibacterial activity against acne-causing organisms. Exfoliates without the aggressive brightening that can trigger rebound hyperpigmentation in darker skin tones. Key component of triple-acid peels (mandelic + salicylic + citric acid) validated in Fitzpatrick IV–V patients for acne and PIH treatment.. It is classified as a Active Ingredient in our database. CAS number: 90-64-2.

What is the Margin of Safety for Mandelic Acid?

not established 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 Mandelic 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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