Materials and methods
Subjects
We screened 80 healthy Filipino female candidates and selected 30 subjects who met the criterion of only a small difference in the melanin index between the left and right sides of the face. These 30 subjects satisfied the additional inclusion criteria of age 30 to 50 years and face melanin index value of 200 to 350. The study was conducted at Clinical Trial Management and Testing Associates, Inc. (Muntinlupa City, Philippines). The study objectives and protocol were
carefully explained to the subjects and their written informed consent was obtained.