I have used this dye before without a reaction. Why does it say to do a patch test before every use?

Sensitivity to oxidative dye ingredients can develop over time. A previous application that caused no reaction does not guarantee that the next one will be trouble-free. That is why the patch test is described as required before each use, not just before the first use.

Do the test on a small area of clean, dry skin and follow the instructions that come with the product. If you see redness, itching, burning or any other irritation at the test site, do not go ahead with the full application. Testing the colour on a strand of hair is not the same thing: the patch test is there to check skin tolerance, not to preview the shade.

This product is ammonia-free, but that does not remove the need for a patch test. Ammonia-free is a formula characteristic, and a practical benefit is that the sharp odour is usually less noticeable. It does not mean the dye is incapable of causing a skin reaction. The product still works as an oxidative colourant, so the same caution applies.

Avoid use on eyebrows or eyelashes and do not apply the dye to irritated, broken or damaged skin. If you have a chronic skin condition, are pregnant or breastfeeding, or take medication, consult a specialist before using a hair colourant.