There’s quite a few brands producing their own colour reducers now, so any that are produced by a colour house and available from your nearest wholesaler should be fine.
Effasor by L’Oréal isn’t a colour reducer so if you’re not sure, read the instructions on the box to check how it works. I’d steer clear of anything sold in chemist/pharmacies just as I wouldn’t ever use box dyes.
Don't forget that the oxidising tint will have lifted their natural anyway exposing the underlying pigment colour, so when you remove the artificial colour, it will look as if it’s been lightened one or two levels compared to the root area. I explain all this to the client so they understand that it will need re-colouring afterwards.
