From the Research
For hyperpigmentation treatment, compounded kojic acid is typically recommended at concentrations of 1-4%, with 2% being the most common effective concentration, as supported by the Cosmetic Ingredient Review (CIR) Expert Panel 1. This concentration range is considered safe and effective for reducing hyperpigmentation, with 2% being the most commonly used concentration.
- The application frequency should be once or twice daily to clean, dry skin, focusing on hyperpigmented areas.
- A pea-sized amount is sufficient for targeted application, and treatment should continue for at least 8-12 weeks to see noticeable results.
- Kojic acid works by inhibiting tyrosinase, the enzyme responsible for melanin production, thereby reducing existing hyperpigmentation and preventing new dark spots from forming.
- It's often more effective when combined with other lightening agents like hydroquinone (2-4%), glycolic acid (5-10%), or vitamin C (5-20%) in compounded formulations.
- Sun protection with SPF 30+ is essential during treatment as kojic acid can increase photosensitivity.
- Some users may experience mild irritation, redness, or dryness, so starting with a lower concentration and gradually increasing frequency can help minimize side effects.
- If irritation persists, reducing application frequency or concentration may be necessary, as suggested by the study on the safety assessment of kojic acid 1. The most recent study on the comparative stability of kojic acid and its derivatives suggests that kojic acid is a more stable and effective option for hyperpigmentation treatment 2. Additionally, a review of the biological activities and safety data of kojic acid and its derivatives confirms its safety and efficacy for human use 3.