Keratin Say: kair-uh-tin Now hair this! This is the hard protein that hair is made of, whether you've got straight red hair, blond curly locks, or black twisty braids. Keratin is also an important part of nails and skin. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.