Mandelic acid is an alpha hydroxy acid (AHA) derived from Prunus dulcis var. amara, or bitter almond. It has been used as a urinary disinfectant for those with chronic urinary tract infections. It is also used dermatologically to repair skin damage from prolonged sun exposure and as an acne treatment. Low doses of mandelic acid are included in some formulations of skin care products and available without a prescription. Medical supervision is required for higher concentrations. Side effects are usually mild, but depend on the concentration used in treatment.
When used as a treatment for urinary tract infections, mandelic acid is combined with methenamine and marketed as mandelamine. This medication is activated in the urine and turns it from a growth-producing medium to a growth-inhibiting medium by making the urine more acidic. It is the formaldehyde created from the acidic urine that actually kills the virus or bacteria. Users may experience gastrointestinal side effects, skin rash, or, rarely, blood in the urine. According to its manufacturer, mandelamine is safe for long-term usage.
Alpha hydroxy acid applied topically speeds up the cycle of skin renewal. It causes the top layers of skin to shed more quickly and reveal new, undamaged skin. Mandelic acid may be used by people of all skin tones to repair skin damage caused by excessive sun exposure and to reduce fine lines and wrinkles. It has been shown in some studies to reduce melasma, or hyperpigmented skin. Some patients in clinical trials showed an up to 50% reduction in the pigmentation of melasma using a 10% mandelic acid lotion for four weeks.
The antibiotic properties of this acid, its ability to speed up skin exfoliation, and slow the production of sebum, make this AHA useful treatment for acne. This may be the treatment of choice for adults who want to treat skin blemishes and reduce the appearance of fine lines. This AHA has been used to reduce acne scars as well.
Some cosmetic companies include mandelic acid in their skin care products. The products have low doses of the AHA, ranging from 10 to 20%. Cleansers, lotions, skin toners, and sunscreen products may be purchased individually or in kits. These products are primarily for people with mild skin problems.
More severe skin conditions may require a higher concentration of mandelic acid. Treatment usually takes place in a doctor's office. A 50-70% solution is generally applied to the patient's face for approximately 3 to 8 minutes. The patient may be able to see results after just one treatment; multiple treatments may be needed for the best results, however.
Compared to other alpha hydroxy acids, mandelic acid has less severe side effects. With low doses of AHA, these side effects may include a mild amount of skin irritation, redness or flaking. With more concentrated doses, side effects may include a day or two of blistered, burning skin, along with some skin discoloration. Those who have been treated with any kind of AHA should take precautions when outside because this type of treatment may increase sensitivity to the sun.