You might think the hair dyes lining the shelves of your local drugstore are the same as professional in-salon formulas, but the truth is that there are major differences between the two. Box dyes are pre-made formulas that are made for all hair types, while salon hair color is custom made for each client. Box dyes ...

Box dyes often contain high levels of ammonia and other harsh chemicals that can strip the hair of its natural oils and cause dryness and breakage. These dyes can also cause uneven color or damage if applied incorrectly or left on for too long.

On most heads of hair, that would mean getting a good 6-8 weeks between touch-ups – but sometimes, even with permanent dye, colour fade can happen within a few weeks. Why does this happen? Typically, hair dyes are water soluble. When you wash your hair, the dye molecules simply dissolve and your new colour rinses away.