Do I really need a patch test before every use, and who should avoid this dye altogether?

Yes, and this is not a formality. Oxidative dyes for eyebrows and eyelashes can cause severe allergic reactions, and a sensitivity can develop at any point — including after years of trouble-free use. That is why a 48-hour patch test is required before each application, not just the first one.

The typical approach: mix a very small amount of the colour cream and developer as directed, apply it to a small area of skin (the inner elbow or behind the ear are common choices), let it dry, and leave it undisturbed for 48 hours without washing the spot. If any redness, itching, swelling, burning or rash appears during that time, do not use the product and rinse the area thoroughly.

Skip this dye entirely if any of the following applies to you:

• you have previously reacted to hair dye, henna or PPD-related colourants;
• the skin around your eyes or brows is irritated, broken or damaged;
• you have an active eye condition or very reactive eyes.

If you have very sensitive skin or have had recent cosmetic procedures in the brow area (such as microblading or brow lamination), it is wiser to wait until the skin has fully settled or ask a qualified specialist first. If the mixture gets into the eye during use, rinse immediately with plenty of water, and seek medical advice if irritation persists.