How to do a Patch Test using L’Oreal Excellence from USA

How to do a Patch Test using L’Oreal Excellence from USA

For this skin allergy patch test, I used a box dye which was purchase in the US. The biggest difference is that the patch test in the instructions is a 2 part. The colour which I had was 4G Dark Golden Brown (Warmer).


A small disclaimer – The photos used are of my arm. At the time I was taking some prescribed medication for migraines, hayfever nasal spray and over the counter antihistamines. I do get eczema, I have no tattoos, I have never smoked and I have never had any henna tattoos.

The test took no longer than 5 minutes to do and this includes mixing up the colourant and developer together, looking for more cotton buds and replacing the battery in my camera.

These are the containers -the only difference is that they aren’t pink.


I first undid the screw top of the developer bottle and poured a small amount in a small plastic container (medicine measure). It is a thick white liquid.


Then the colourant tube – undo the lid and pierce the foil seal with the pointed section on the top of the lid. Squeeze an equal amount of the pale yellow colourant creme into the container.


There is a bit of  clear coloured liquid which comes out first. This is not what you use for the patch test – this creates an air tight seal and prevents any oxygen getting to the colourant and the colourant from going off. Hopefully you can see it in this close up.


There wasn’t a ratio on the tube of colourant or the developer bottle so I guessed equal parts.

Mix together carefully, with a plastic stick (I removed the cotton wool from a cotton bud) and then apply a 10p size (quarter sized) onto the inner elbow or behind the ear with a cotton bud.



It smells the same as the UK mix.

This is the patch after a few minutes.


After 15 minutes


After 25 minutes, there is a shadowy brown around the main patch test. This is where the mix has travelled slightly.


After 45 minutes the mixed colour has almost dried but it is muddy looking. Also the shadow marking had spread.


As I did with the UK patch test, I gently went over the area with a wet cotton bud to remove the residue and clean up the area so the dye wouldn’t go on any clothing.


Here is my arm after I cleaned off the residue with a damp cotton bud. There was no stinging or any discomfort.

I shall update after 48 hours.

Edit:- 48 hours later and my arm is clearer but from all the hair dyes I’ve patch tested, this is the only one which seems to have made the hairs on my inner arm more visible. usa-48hrs

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