What is the function of these fats?
- They help to reduce the friction of hair fibres against each other
- They also help to repel water
Effectively, they offer a degree of protection. However, when your hair gets exposed to sun the ultra violet light (UVA and UVB rays) degrades this fatty layer and you get sun damaged hair. This is why protective styling is just as important when it is very hot as it is when it is very cold.