KOJIE SAN SKIN LIGHTENING SOAP. Kojie San is formulated with all-natural kojic acid formula that helps lightens dark spots due to acne, age spots, freckles, sun-damaged skin, and other skin pigmentation. In addition to skin-lightening effects, kojic acid also contains some antimicrobial properties. It may help fight off several common types of bacterial strains even in small dilutions. This can help treat acne caused by bacteria in the skin. It may also lighten scars from acne that haven't faded yet leaving the skin radiantly spotless.