“Mild,” (lye-free) or home hair relaxers often contain a reducing agent such as calcium hydroxide, lithium hydroxide or guanidine hydroxide as the “active ingredient.” Lye is sodium hydroxide and is considered a “strong base” in its chemical activity—but the other straightening agents are also “strong bases” which break bonds in the hair shaft in order to allow the hair shape to be altered. If you use a relaxer to straighten or loosen curls, make sure you are extra gentle with your hair and use plenty of moisture and protein if tolerable. Always provide protection for the skin and eyes when using these products, and use in an area with good ventilation.
Chemical Hair Relaxers: Does “Lye-Free” Matter?
Lye-free relaxers contain chemicals as strong as lye, so use with caution.