Well, when you're just getting this random information off the internet, it's hard to know what to believe sometimes.

The chemical service you're considering might very well work for you. I think the key is just to have a good stylist who knows how to apply the product right without overlapping the chemicals.

Chemical treatments in general make your hair more fragile. So, just treat your hair gently.

This article is talking about perms, but the chemical is the same:

Want Curls With Less Damage? Try This New Way To Perm!: Beyond the Beauty Pages: Beyond the Beauty Pages: Self.com


On the other hand, "thio-free" perms use an ingredient (amino acid) called
cysteamine. Cysteamine also breaks down the disulfide bonds in your hair. This
chemical doesn't have the strong odor often associated with thio but it isn't as
effective in producing permanent waves as thio perms (which also means less
damaging).

Does "thio-free" mean damage free?
Unfortunately, that is
not the case. While
cysteamine-based perms are less smelly and less damaging, that certainly doesn't
mean no smell or no damage. This ingredient is still chemically changing
your hair, which is a damaging process. Cysteamine doesn't work quite as well
as thio which could be a good or bad thing depending on how you look at it! If
you want a slightly looser wave that doesn't last as long as traditional perming
then "thio-free" (or cysteamine) perms are worth a try.
Here is a positive viewpoint from a stylist:

Keratin hair straightening is flat-out fabulous for the formerl... - Topix

The Pravana Keratin Fusion is a nice system. I use this product. HOWEVER it
cannot be compared to a Keratin Treatment. Pravana is a chemical straightener
that permanently alters the internal bonds of the hair. The Brazilian Keratin
Treatment is an external product that does not alter the bonds.
These
treatments all have a place in the straightening world, including the Japanese
straightening. But they are each quite different in many ways from each other
and serve a different purpose.
The key is to find a hair
straightening specialist who is proficient in all of the choices available. One
who understands all the chemistry involved. They will help to guide you to the
best treatment for your individual hair type and needs.
Here is the whole process step by step:

Pravana's Keratin Fusion: Before, During and After Photos

If you have any concerns, maybe you should discuss it with your stylist. Hopefully, there is someone who posts on this board can really advise you.
fine/med, dense, low porosity

low-poo: SM Curl & Shine, SM African Black Soap Shampoo
RO: One 'n Only Brazilian Tech Keratin Smoothing Cond.
leave-in: Giovanni 50/50 cond.
stylers: KCCC, KMFUM