Hyperpigmentation, including conditions like melasma and post-inflammatory hyperpigmentation (PIH), is a common skin concern. Glycolic acid, an alpha-hydroxy acid (AHA), is frequently used in skincare for its exfoliating properties. But can it effectively reduce hyperpigmentation? Let's explore what scientific studies have found.
What Is Glycolic Acid?
Glycolic acid is a water-soluble AHA derived from sugar cane. Its small molecular size allows it to penetrate the skin easily, promoting exfoliation by breaking down the bonds between dead skin cells. This process can help improve skin texture and tone.
Scientific Evidence on Glycolic Acid and Hyperpigmentation
1. Post-Inflammatory Hyperpigmentation (PIH)
A study involving patients with darker skin types (Fitzpatrick IV to VI) assessed the effects of glycolic acid peels combined with a topical regimen. The group receiving glycolic acid peels showed more rapid and greater improvement in PIH compared to the control group. The peels also led to increased lightening of normal skin, with minimal adverse effects. [link]
2. Melasma Treatment
In a study of Asian women with melasma, participants applied a cream containing 10% glycolic acid and 2% hydroquinone twice daily, along with glycolic acid peels every three weeks on one side of the face. Both sides showed improvement, but the side receiving peels had subjectively better results, though the difference was not statistically significant. [link]
3. Combination Therapies
Combining glycolic acid with other agents like hydroquinone has been shown to enhance treatment outcomes. A study found that a cream containing 4% hydroquinone, 10% buffered glycolic acid, vitamins C and E, and sunscreen was more effective in treating melasma than sunscreen alone. Seventy-five percent of patients using the combination cream showed improvement, compared to 13% in the sunscreen-only group. [link]
Safety Considerations
While glycolic acid is generally safe, it can cause skin irritation, especially at higher concentrations. A case report highlighted severe hyperpigmentation and scarring in a patient who underwent a 70% glycolic acid peel while on low-dose oral isotretinoin therapy. This underscores the importance of professional supervision and caution when combining treatments. [link]
Scientific studies suggest that glycolic acid can be effective in reducing hyperpigmentation, particularly when used in combination with other treatments like hydroquinone. However, results can vary based on individual skin types and conditions. It's advisable to consult a dermatologist to determine the most appropriate treatment plan for your skin.