What safety steps are mandatory before every application?

Because oxidative dyes can trigger delayed allergic reactions, the manufacturer requires a patch test 48 hours before every single use — not just the first time. Apply a tiny amount of the mixed product behind the ear or on the inner forearm, leave it uncovered, and watch for redness, itching, swelling, or burning. If any reaction appears, do not proceed. Do not use the dye on broken, sunburned, or irritated skin, and avoid it entirely if you have ever reacted to hair dyes, black henna tattoos, or paraphenylenediamine (PPD)-containing products. Keep the mixture away from the eyes; if contact occurs, rinse immediately with plenty of lukewarm water. The product is not intended for anyone under 16. Store both components tightly closed, in a cool, dark place, and discard any mixed portion — it cannot be saved for later use.