The day you get a relaxer for your hair, nobody can tell you you're not fabulous. That hair is swishing and swinging, moving to the rhythm of your strut. But you likely haven't given much thought to the process your hair has just undergone (understandable, because the great look makes it hard to focus on much else). If you want to keep a healthy head of hair, it's important to know just a little about the type of relaxer used. Lye and no-lye relaxers can provide similar results, but the road to fabulous is a bit different depending on which you've used.
Both lye and no-lye relaxers are chemically based straightening agents. Lye relaxer products contain sodium hydroxide, which produces dramatic straightening effects that last for several weeks following a single application. It is also found in drain cleaners and has a varied pH of 10 to 14; the higher the number, the faster hair gets straightened and the greater the possibility of damage. No-lye relaxers have guanidine hydroxide in them, which is a bit less damaging than its sodium counterpart.
Both lye and no-lye relaxers are based on potent chemicals that alter the composition of your strands. Both sets of chemicals penetrate into the cortical layer of the hair shaft, according to Skin Biology, and loosens up those curl patterns. Both initiate a process that is not reversible, once it has been started, and both result in bone straight hair once the process has been completed.
Guanidine hydroxide (no-lye) relaxer products are a bit less potent than the sodium hydroxide lye products. This makes a no-lye perm type a bit gentler on your hair, though it may not get quite as straight as lye products can get it. No-lye formulas generally have to be mixed with an activator before application, while lye perm products come ready to apply.
Regardless of whether you use a lye or no-lye relaxer, your hair has to be in the best condition possible to withstand the alteration process. While you can do this at home, it's best to leave the process in the hands of a hair professional; otherwise, you may end up with damaged locks that can barely stay on your head, let alone bounce. Hair relaxed with both lye and no-lye relaxer products must be conditioned often, with a deep conditioner at least once a week to restore some of the moisture zapped during the relaxing process.