This invention relates to a method for inhibiting melanin formation in a subject comprising administering an effective amount of an acerola-derived polyphenol compound, an acerola polyphenol fraction, or the other polyphenol compound to a subject. This method comprises whitening the subject's skin by the inhibition of melanin formation. This method also comprises administering synergistically effective amounts of an acerola-derived polyphenol compound, an acerola polyphenol fraction, or the other polyphenol compound in combination with ascorbic acid or an ascorbic acid derivative to a subject.