1. Hair is made up of a tough protein called keratin.
2. Hair is 50% carbon, 21% oxygen, 17% nitrogen, 6% hydrogen, and 5% sulphur.
3. When wet, a healthy strand of hair can stretch an additional 30% of its original length.
4. Hair grows slightly faster in warm weather, because heat stimulates circulation and encourages hair growth.
5. All hair is dead, with the exception of the hair that’s still inside of your scalp.
6. Hair contains information about everything that has ever been in your bloodstream, including drugs, and is one of the most commonly used types of forensic evidence.
7. The only thing about you that can’t be identified by your hair is your gender, men’s and women’s hair are identical in structure.
8. Black is the most common hair color. Red is the rarest and only exists in about 1% of the world’s population, with blonde hair found in 2%.
9. As soon as a hair is plucked from its follicle, a new one begins to grow.
10. Hair can grow anywhere on the human body with the exception of the palms and soles, eyelids, lips, and mucous membranes.
11. Goosebumps from cold or fear are the result of hair follicles contracting, causing the hair and surrounding skin to bunch up.
12. The average number of hair strands varies by natural color, with blondes having the most and redheads having the fewest.
13. Balding only begins to become visible once you’ve lost over 50% of the hairs from your scalp.
14. At any given time, 90% of the hairs in your scalp are growing, while the other 10% are resting.
15. A single hair has a lifespan of about five years.