Found in: Commercial permanent hair dyes (most of your over the counter dyes).
Used to: Remove color from the hair and swell the hair cuticle so it can be refilled with chemical color.
Could be harmful: Ammonia opens the hair cuticle and deposits the color. While this gives you that awesome new hair color, the process damages the hair cuticle that eventually degrades the hair's structural integrity.
The result will be dry, brittle, unhealthy looking hair. Not to mention possible skin, eye and lung irritation.
Subistitutes to watch for in Ammonia-free colors (these are not much better and in some cases worse):
- Ethanolamine (also called monoethanolamine)
- Cocamide MEA
- Aminomethylpropanol (AMEA)