* CAN IT TREAT EXISTING PIGMENTATION? tranexamic acid can treat existing pigmentation effectively and products containing the ingredient are recommended for preventing post-inflammatory pigmentation (PIH), which can be a common side effect of laser treatments. * HOW EXACTLY DOES IT WORK? it blocks the transfer of pigment from melanocytes (pigment-producing cells) to keratinocytes (the keratin-synthesising cells found in the outermost layer of skin – the epidermis). * DOES IT MAKE SKIN MORE SENSITIVE TO SUN? Absolutely not. In fact, tranexamic acid decreases the skin’s sensitivity to UV – this is why he ingredient is so popular in Asia and India.