Sensitive skin is a new term that has emerged in recent years, usually referring to a self-conscious inability to tolerate any skin care products and cosmetics applied to the skin. When the skin encounters external stimuli, it tends to produce symptoms such as erythema, papules, flaking, and even painful itching, burning, and pain. This is mainly due to impaired skin barrier function, increased sensory nerve signal input and enhanced immune reactivity. Sensitive skin can be judged by subjective, semi-subjective and objective evaluation, among which the lactic acid test in semi-subjective evaluation is currently the main method to judge sensitive skin: 10% lactic acid is applied to the nasolabial folds and either cheek under room humidity, and the sensitivity reaction of the subject is rated on a 4-point scale at 2.5 and 5 minutes, respectively, and then the two scores are added together and those with a score greater than 3 are sensitive skin. (It is best to go to the hospital for testing.) Sensitive skin should use skin care products that are soft in nature and have a single component for skin care. You can choose medical skin care products that contain natural plant amaranth, hyaluronic acid, ceramides and other ingredients or living water. And it also needs to have some lipid content in order to lock in moisture.