Malic Acid
INCI · Malic Acid · also hydroxysuccinic acid, apple acid
How it works
Malic acid is an alpha-hydroxy acid naturally found in apples and other fruits, functioning by loosening the bonds between dead skin cells on the stratum corneum to promote exfoliation and reveal smoother, more even-toned skin beneath. Compared with glycolic acid, it has a larger molecular size, which generally results in slower skin penetration and a milder exfoliating action.
The evidence
Malic acid is frequently studied as part of AHA blends rather than in isolation, with combination formulas (such as malic acid alongside glycolic or lactic acid) showing improvements in surface texture, tone evenness, and mild photodamage in clinical exfoliation research. Its humectant properties, owed to its hydroxyl and carboxyl groups, also contribute a mild hydrating effect alongside exfoliation, distinguishing it somewhat from purely keratolytic acids.
Suitability
Malic acid suits combination and oily skin seeking gentle-to-moderate exfoliation, and is often chosen for sensitive skin that cannot tolerate glycolic acid due to its comparatively larger molecule size and slower activity.
- Combination and oily skin: supports texture and pore appearance
- Sensitive skin: milder than glycolic acid but still requires patch testing
- Pregnancy: use with caution and at low concentrations, as with other AHAs
Concentration
Leave-on products typically use malic acid between 1% and 10%, often in combination with other AHAs rather than as the sole acid.
Conflicts & combinations
Malic acid should not be layered with retinoids in the same routine, as the combined irritation potential of acids and retinoids can compromise the skin barrier; it should also be separated from benzoyl peroxide to avoid excess dryness and irritation.
- Avoid combining with retinoids or benzoyl peroxide in the same application
- Commonly blended with glycolic, lactic, or citric acid in multi-acid exfoliants
- Daily SPF is essential due to increased sun sensitivity from AHA use
- dullness
- uneven texture
- enlarged pores
- redness
- Effective from
- 5%
- Max safe
- 10%
Is malic acid gentler than glycolic acid?
Yes, its larger molecular size generally means slower skin penetration and a milder exfoliating effect compared with glycolic acid.
Can malic acid be used with retinol?
It is generally advised to avoid combining malic acid with retinol in the same routine, as layering acids and retinoids increases irritation risk; alternating AM/PM or nights is safer.
Is malic acid safe during pregnancy?
It is generally used with caution during pregnancy, similar to other AHAs, and lower concentrations under professional guidance are recommended.
Does malic acid increase sun sensitivity?
Yes, like other AHAs, malic acid can increase photosensitivity, making daily sunscreen use important during treatment.
What products commonly contain malic acid?
It is frequently found in multi-acid exfoliating toners, peels, and serums, often blended with glycolic, lactic, or citric acid for a balanced exfoliation profile.