Encyclopedia
Science
Keratin
The protein that makes up 95% of every hair on your body — including your beard.
Keratin is a fibrous structural protein — the same material that forms hair, nails, and the outermost layer of skin. Understanding keratin explains why hair damage matters: once a hair leaves the follicle, it's dead protein. Nothing can 'repair' it — products can only coat, protect, and slow further damage.
Key Facts
- ›Makes up ~95% of every hair on the human body.
- ›Once out of the follicle, hair is dead protein.
- ›'Repair' products actually mean 'coat and protect.'
- ›Damaged keratin cannot be structurally rebuilt.
- ›Sulfur bonds in keratin give hair its strength.
Full entry coming soon — our editors are finishing it now.
