Many women who get Brazilian keratin hair straightening treatments swear that it makes their hair grow longer faster. But in truth that is probably just an optical illusion.

Your hair already contains keratin proteins. What a keratin treatment does is add additional keratin proteins to your hair, then use head to seal them in, straightening your hair at the same time.

Before frizzy or curly hair is treated with keratin, it is often coiled up like a spring. But when you add additional keratin and then flatten these coiled hairs out with a hot hair iron, it makes the hairs appear to be longer even though their actual length doesn’t change.

Keratin Hair Treatment —  Does Keratin Make Your Hair Thicker?

So if a keratin hair treatment doesn’t actually make your hair longer, does it at least make it thicker?

Yes. When you add additional keratin proteins to those already found naturally in your hair, then bind them in using heat, it can thicken the individual hair follicle, giving you thicker, richer, and more luscious hair. This is especially true for women with kinky, frizzy, or naturally curly hair.

Keratin Hair Treatment — Does Eating Protein Help Your Hair Stay Strong?

Your Brazilian keratin hair straightening treatment can last anywhere from a few weeks to a few months, giving you straight, strong, and vibrant hair the entire time. But does adding more protein to your diet help keep your hair looking more luxurious.

Yes and no. Once your hair is grown out, what you eat doesn’t have any effect on it. But eating more protein will nourish the new hair as it begins to grow from your scalp.

Conversely, a diet that is poor in vitamins, minerals, and other important nutrients can cause your hair to thin, and eventually fall out. So it’s important for your hair to eat a healthy diet.