Manic Panic are Fully Vegan Friendly Hair Dyes.Leave colour on hair for 15 minutes or longer. Manic Panic will process fully in 15 minutes at normal room temperature. The use of an infra red heat lamp will reduce the processing time to between 5 and 7 minutes and can produce a deeper coloration with longer lasting properties. For resistant hair it is advisable to place a plastic cap on the hair and leave on for 30 minutes or longer.