Mandelic Acid
만델릭애씨드
An alpha hydroxy acid (AHA) that exfoliates the skin and can help with acne and hyperpigmentation.
What is Mandelic Acid?
CAS Number
90-64-2
Formula
C8H8O3
Molecular Weight
152.15 g/mol
Also known as: MANDELIC ACID, dl-Mandelic acid, Phenylglycolic acid, Paramandelic acid, Amygdalic acid
What does Mandelic Acid do for skin?
Mandelic acid, an alpha hydroxy acid (AHA) derived from bitter almonds, works by weakening the intercellular bonds (desmosomes) between corneocytes in the stratum corneum, facilitating the exfoliation of dead skin cells. Its relatively larger molecular size compared to glycolic acid results in slower, more even penetration into the skin, leading to reduced irritation. It is also lipophilic, allowing it to penetrate sebaceous follicles, which contributes to its efficacy in treating acne. Furthermore, mandelic acid exhibits mild antimicrobial properties and can inhibit tyrosinase activity, aiding in the reduction of hyperpigmentation.
Typical concentration: Typical concentrations in cosmetic formulations range from 5-10% for leave-on products and up to 15-20% for stronger treatments. Professional chemical peels can utilize concentrations from 20-40%.
Is Mandelic Acid safe?
The CIR Expert Panel has deemed mandelic acid safe for use in cosmetic formulations when formulated to be non-irritating and when appropriate sun protection is used. Due to its larger molecular size, it generally causes less irritation and erythema compared to other AHAs like glycolic acid. It can increase skin's sensitivity to the sun, necessitating daily sunscreen use.
What does the research say about Mandelic Acid?
Efficacy of mandelic acid chemical peel in melasma
Khunger N, Kumar C. J Cosmet Dermatol. 2017 Mar;16(1):50-57.
Comparative study of efficacy of mandelic acid peel versus glycolic acid peel in acne vulgaris
Ali S, Hasan S, Khan MS, Ansari M, Singh S, Singh M. Indian J Dermatol Venereol Leprol. 2012 Mar-Apr;78(2):211-2.
Evaluation of efficacy and safety of mandelic acid peel in treatment of superficial acne scars
Kumar C, Khunger N. J Cosmet Dermatol. 2018 Jun;17(3):362-368.
Regulatory Info
Can I mix Mandelic Acid with other ingredients?
Using AHA and BHA together is aggressive exfoliation that can strip the skin barrier. Use on alternate nights for best results.
Other AHAs (Glycolic, Lactic, etc.)
Layering multiple AHAs (e.g. glycolic + lactic) is excessive. One AHA per routine is enough. More doesn't mean better.
Retinoids and AHAs are both strong exfoliants. Using them together can cause severe irritation, redness, and barrier damage. Alternate on different nights.
General guidance
AHAs increase UV sensitivity. Make sure SPF is in your morning routine when using AHAs.
PHAs
Using AHA and PHA together increases total exfoliation. PHAs are gentle but adding them to AHAs may be too much for sensitive skin.
Vitamin C with AHAs can be too acidic for some skin types. If you experience stinging, use them in separate routines.
Peptides
AHAs can reduce peptide effectiveness. Best to use acids and peptides in separate routines for maximum benefit.
Growth Factors
Growth factors like EGF may lose effectiveness when layered with AHAs. Consider using in separate routines.
AHAs lower skin pH while niacinamide works best at neutral pH. Together they may reduce niacinamide's effectiveness. Consider using on alternate routines.
Both are drying. Benzoyl peroxide with AHAs can over-dry and irritate skin. If you use both, apply on alternate days.
Hydroquinone
AHAs increase hydroquinone penetration, which can cause more irritation. Use lower concentrations if combining.
Azelaic acid with AHAs can cause irritation for sensitive skin. Both exfoliate through different mechanisms so go slowly.
Tranexamic acid is generally safe with AHAs, but combining multiple brighteners with exfoliants can irritate sensitive skin.
Denatured Alcohol
Alcohol-based products with AHAs increase drying effect and potential irritation. Look for alcohol-free formulas.
AHAs increase arbutin penetration, which can cause mild irritation on sensitive skin. Use lower concentrations if combining.
Glycolic acid + ceramides is a smart pairing. The acid exfoliates while ceramides immediately repair the barrier.
Unlike retinol, bakuchiol is stable at acidic pH and does not conflict with AHAs. No need to separate them — you can safely use both in the same routine.
Read all ingredient interaction guides for layering order and science-backed advice.