Mandelic acid is an alpha-hydroxy acid. It is an extract of bitter almonds. The exact mechanism is not clearly known, but research suggests it may reduce the production of melanin (skin pigment). This is how it works to treat hyperpigmentation, melasma, dark spots, etc.
Common side effects of Mandelic acid
Application site reactions (burning, irritation, itching and redness)
Reviewed By Dr. Rajeev Sharma