For any permanent form of colour that will come in to contact with the scalp a patch test should always be undertaken first at least 24 hours prior to the service being undertaken. This is to ensure against any allergic reaction. In most cases there is no allergic reaction, however the worst case scenario can lead to death.
Through years of experience and using all the brands, we generally use Goldwell as this has proven to give the best result. This said we use Loreal for bleach, some toners and for some highlifts. We always endeavour to put our customers first and will only use the best products we have access to, we do not stick to just one brand.