The main differences between keratin treatments and Brazilian blowouts is that Brazilian blowouts are the "lighter" option, and are more versatile when it comes to the type of results you want with your locks. If you're not looking for a bone straight look, you can work with your stylist when it comes to a Brazilian blowout, as they can adjust the temperature of the straightener for what's right for you (via InStyle). However, if you have wild or unruly hair, a keratin treatment is the stronger option, and may be what you need to tame your hair for that ultra sleek effect.
"Generally speaking, you will get more of a smoothing and deep-conditioning effect with a keratin treatment ... as it contains less harsh chemicals and silicones, which weigh down the hair and clog the scalp as compared to a Brazilian blowout," salon owner Arsen Gurgov told Today, who also commented that modern keratin treatments are more gentle and have been using less heat.
Another thing to note about keratin treatments is that if you have colored hair, keratin treatments actually lock in the pigment to make the color last longer while increasing vibrancy (via Setsuko Salon). It should also be noted that with keratin, you must wait 72 hours before washing or styling your hair, whereas with Brazilian blowouts, you're free to go about your hair care routine as soon as you leave the salon.
