The Mexican actress credits her thick dark hair to her grandmother - who trained as a beautician and made potions for government officials and their wives to boost their hair and looks - who made her use unusual treatments and even shaved her head when she was younger to help it grow.
She told the new issue of Allure magazine: "She started working on my skin when I was 12 or 13. I never used soap on my face. Once, she shaved our heads and put egg on it and all these things. But I have to give her credit - my hair is great."
Salma, 44, also revealed she has become more comfortable with herself and her sexuality as she has gotten older, and she wishes she could have been more confident with herself when she was younger.
The actress - who has a three-year-old daughter Valentina with her French billionaire husband Francois Henri Pinault - said: "As a woman, you should be more at ease with your sexuality when you are in your 40s.
"You are more self-assured about that part. And that`s the way it should be. If you are a girl who cannot walk in heels, it doesn`t matter how beautiful you are. If you look like a chicken that`s been spiked in the feet, it`s not going to be sexy."