There are a small number of individuals who show an allergic reaction to hair colors/peroxide. In very rare cases this reaction may be severe. In order to reduce the risk of an allergic reaction it is important to carry out a skin sensitivity test. This skin sensitivity test must be carried out 48 hours before each application to ascertain if there is an allergy or sensitivity against the product or if such has emerged since the last application. In exceptional cases irritations can occur only after 72 hours. If you know that hypersensitivity could be on hand, leave the mixture for 72 hours on the skin.
Allergy Test: Mix 1cm of Brow Code Tint with 1 cm of Oxidant 3% liquid or crème . Apply a small amount to a small area on the inner bend of the elbow or behind the ear. Allow to dry and leave uncovered for 48 to 72 hours, then clean thoroughly. If any irritation occurs during this time do not carry out the treatment.