I don't have any scientific explanation for how it straightens, but they keep saying that the more porous hair is, the better the treatment "bonds". Natural hair cuticle layers are more likely to lay flat and therefor are less porous.
That's all I got... I'm still doin it! lol
http://www.naturallycurly.com/curlreading/straightening/brazilian-keratin-treatment
Living in the heat and humidity of South Florida, Heather Frankel’s fine curls often turned to frizz. One day, she saw a curly Brazilian friend, and her hair was noticeably longer and straighter.
“She told me about the treatment,” Frankel says.
That would be the Brazilian Keratin Treatment — a curl relaxer that has taken the United States by storm in recent months. Known as Brazilian Keratin Treatment, Brazilian Hair Straightening, Brazilian Blowout or just BKT, it first came to the United States a few years ago. But over the past year, a growing number of hairdressers have embraced it.
Thermal reconditioning — also known as Japanese straightening — seems like yesterday’s news compared to this hot import from Brazil.
Frankel, who was considering doing thermal reconditioning, is thrilled with the results. She says hair has body and shine, and only takes five minutes to style. And frizz is a thing of the past.
“It opens the door to hairstyles I’ve always wanted but didn’t think I could have,” she says. “Now you can see the layers, you can see the highlights, you can see the flips. I am so happy - you have no idea.”
Stylist Tiffany Vance, owner of Hedda Hair and Body Bliss in Joliet, Ill., began doing the chemical service in June.
“I’ve had extremely good results,” Vance says. “It’s good for all curl types, especially those who color their hair.”
A big selling point of BKT is that it doesn’t have the strong chemicals - sodium hydroxide and ammonium thioglycolate - that are in most relaxers and straighteners. These harsh chemicals can cause damage and breakage.
Instead, the active ingredient is keratin, a protein similar to a component in human hair, which naturally straightens the hair. Unlike many chemical processes, Brazilian Keratin Treatment works best on hair that’s been color processed, highlighted or chemically treated.
Unlike other types of relaxers, the treatment can be used over any kind of straightening.
“The keratin fits right on the hair’s cortex,” says Nadine Ramos of Brazilian Hair Straightening Inc. in New York’s East Village. “It works as a treatment and a straightener at the same time. It actually strengthens the hair’s cuticle.”
Ramos first heard about the treatment when she got her hair straightened four years ago by a Brazilian importer. She liked it so much, she decided to get licensed so she could provide the service to other women. She has been importing it for three years. But it’s popularity has soared this year, she says.
“Stylists see that it works and that it’s time efficient,” Ramos says.
On average, the process takes around two hours, and starts at around $150. Thermal reconditioning, on the other hand, can take five to six hours and usually costs $500 and up.
With Brazilian Keratin Treatment, a stylist applies a solution made with keratin. Using a 450-degree iron, the hairdresser seals the formula onto the outer layer of the cuticle. It sticks to the cuticle’s rough edges, trapping moisture and hydrating the hair.
Initially, the hair may seem too straight for many curlies.
“My hair was stick straight,” Frankel says. “It was beyond Marcia Brady straight. I’ve never had my hair so straight in my entire life. Personally, I didn’t like how straight it was.”
Unlike thermal reconditioning, the process washes out so the hair gets wavier over time. Another advantage over thermal reconditioning is that the hair can be curled, giving people more styling options.
“The hair has body and natural movement,” Ramos says.
The process typically lasts from six weeks to a few months — longer for color treated hair — depending on how often the hair is washed. There is no demarcation line between the treated hair and new growth.
Really? Well - I read some where that this 'takes' better on Chemically processed hair....
. I also only use the MT when i wash, so now im slacking on that use as well.....
At that point I knew I would do it myself, if I decided to. Either that or take a trip to see DSD! 
YUP
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