Yes like the other responders mentioned, in my opinion, the manufacuter is referring to
- NON Body art henna and
- Thio relaxers, one that comes to mind is the wave nouveau relaxer
- permanant dyes
I took the passage below from this website
Chemical Hair Straightening Faqs
Ammonium Thioglycolate
Ammonium thioglycolate (nicknamed "thio relaxer") is much less drastic in its action than the sodium hydroxide and even, in some cases, the guanidine hydroxide. It acts a little differently by softening and relaxing overly curly hair through changes to the hair's cystine linkage.
Thio works on the same formulation principles as thioglycolate permanent waves. With a pH of 9-9.5, these are also considered to be less damaging, yet still require a neutralization step. Thioglycolate relaxers are usually in cream or gel form and can be preceded by a pre-softener.
Since thio relaxers are considered much milder, the risk of hair damage is also reduced by comparison to the sodium hydroxide.
I also just pulled the passage below from this site:
No Lye Relaxer Vs. Lye Relaxer | eHow.com
Chemicals
•The difference between the two relaxers is the chemical compound responsible for the hair-straightening action. In lye relaxers, this is sodium hydroxide, and in no-lye relaxers, it is guanidine - which comes from the same metal hydroxide family as sodium hydroxide. The higher pH balance of lye relaxers means they work fast and increase the risk of over-processing the hair.
Read more: No Lye Relaxer Vs. Lye Relaxer | eHow.com
No Lye Relaxer Vs. Lye Relaxer | eHow.com
From what I have pulled from these websites, I would not suggest doing this relaxer on previously relaxed hair. No matter how much we try the relaxer tends to overlap onto the previously relaxed section if you want to apply it, I would ensure the previously relaxed hair is well protected with vaseline.
