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Comparative effectiveness of alpha-hydroxy acids on skin properties
1Walter Smith Consultants, 46 Wakeman Road, New Canaan, CT, 06840 USA.
International Journal of Cosmetic Science
|February 28, 2009
Summary
Lactic acid and glycolic acid are effective alpha-hydroxy acids for skin renewal and reducing wrinkles. Lactic acid, particularly the l(+) form, offers superior hydration and fewer irritation complaints compared to other acids tested.
Area of Science:
- Dermatology and Cosmetic Science
- Biochemistry of Skin Aging
Background:
- Alpha-hydroxy acids (AHAs) are widely used in skincare for their exfoliating and rejuvenating properties.
- Understanding the differential effects of various AHAs on skin physiology is crucial for product development.
Purpose of the Study:
- To evaluate the efficacy and tolerability of different alpha-hydroxy acids on key skin properties.
- To compare the effects of glycolic acid, lactic acid (l(+) and d(-) isomers), citric acid, hydroxybutyric acid, and malic acid.
Main Methods:
- Assessment of stinging potential on sensitive skin.
- Measurement of skin cell renewal rates.
- Quantification of skin moisture content over a six-week period.
- Evaluation of wrinkle reduction efficacy.
Main Results:
- Lactic l(+) and glycolic acids demonstrated the highest efficacy at equimolar concentrations.
- Lactic l(+) acid showed significantly lower irritation and fewer consumer complaints than d(-) lactic acid and glycolic acid.
- Both lactic acid isomers and glycolic acid improved skin hydration and reduced wrinkles, with lactic l(+) being superior in tolerability.
- Higher concentrations (>1.5 m) of lactic and glycolic acids revealed greater differences in stinging potential, favoring lactic l(+) acid.
Conclusions:
- Lactic acid (both isomers) and glycolic acid are the most effective AHAs for skincare formulations.
- Lactic acid possesses a slight technical advantage over glycolic acid, particularly the l(+) isomer due to its enhanced tolerability.
- Neutralized forms of lactic acid (l(+) and d(-)) act as superior moisturizers.
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