Even when used as directed, Nair and other depilatory treatments can cause skin irritation. Nair contains active components such as calcium hydroxide and potassium hydroxide. These chemicals cause the hair shaft to expand, allowing the chemicals to penetrate the hair and break it down. As a result, the hair will be removed easily with no need for further treatment. Using Nair can also lead to skin reactions such as redness, itching, or pain. If you have an allergy or sensitivity to products containing epinephrine (adrenaline), then Nair should not be used on any part of your body. Epinephrine is found in many common medications including Adrenalin, Lantus, and Sympathomimetics. Also, if you have thinning hair due to alopecia areata, using Nair could make this condition worse. Finally, Nair can release small particles into the air that may contain bacteria or chemicals that can enter your lungs. If you have asthma or other respiratory conditions, then you should avoid areas where there is much dusting of hair all over your house. In conclusion, Nair is useful for removing unwanted facial hair but must be used with caution because it can be harmful if not used properly.