Even if you never cut it, your hair would stop getting longer. Every hair on your head has a built-in timer.
How long does a hair grow?
Hair on your head grows about 1 centimeter a month. But each hair only keeps growing for a few years. Then it stops, rests for a few months, and falls out. A new hair grows in its place. So each hair can only get so long.
Why are eyelashes so short?
Eyelashes and eyebrows only grow for weeks or months, not years. That is why they stay short.
What happens to the ends?
Over time, brushing, washing and sunlight wear out the old ends. That is how split ends happen.
One more thing
You can lose 50 to 100 hairs a day without even noticing. Luckily, their timers never all run out at once.
Sources
- Journal of Clinical Medicine, via PubMed Central: Integrative and Mechanistic Approach to the Hair Growth Cycle and Hair Loss
- BBC Science Focus: How your hair's growth cycle impacts its length
- Cleveland Clinic: Terminal Hair
- Cleveland Clinic: Hair Follicle
- Cleveland Clinic: Telogen Effluvium
- Journal of Optometry, via PubMed Central: The eyelash follicle features and anomalies: A review
- International Journal of Trichology, via PubMed Central: Hair Cosmetics: An Overview
- Cleveland Clinic Health Essentials: Can the Sun Damage Your Hair?
- American Academy of Dermatology: Teaching your child healthy hair care habits
- American Academy of Dermatology: 10 hair care habits that can damage your hair
- American Academy of Dermatology: Do you have hair loss or hair shedding?
- NHS: Hair loss
- Cleveland Clinic Health Essentials: How To Make Your Hair Grow Faster
