Dark Chestnut permanent hair colour. Bigen Permanent Hair Color is ideal for those looking for long lasting 100% gray coverage or to enhance their natural hair color. Bigen permanent hair color is ammonia free and requires no hydrogen peroxide. The unique powder formula is activated by water to naturally open the hairs cuticle to deposit rich, natural color into even the most stubborn gray hair. This deposit only color is the gentle choice and has been proven for over thirty years. Bigen is the #1 selling permanent powder hair color. Bigen produces optimum darkening results regardless of your natural hair color, consistency, condition, length or style.