Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Eyebrow & Eyelash Growth
Name: Glenn
Status: other
Grade: other
Location: Outside U.S.
Country: Canada
Date: Fall 2011

Question:
I don't know if the following Question is in your criteria or not, but here's the question; Why does human eyebrows grow, while human eyelashes on the same human doesn't?


Replies:
Hi Glenn,

Eyelashes have a different growth cycle from your eyebrows as do eyebrows have a different growth cycle from the hair on your scalp.

It's the anagen phase which is the active phase of the growth cycle which is shorter in time for eyelashes, that stops the growth and defines the length of your eyelashes.

The length in time for the anagen phase is genetically defined.

The anagen phase for eyelashes is timed in days, whereas eyebrows are in this active phase for weeks, while the hair on your scalp continue to grow for years.

-Alex Viray


Glenn,

It is a little hard to answer your question, as it contains a mistaken premise. Both eyebrows and eyelashes grow. just like all the hairs on your head and on your arms and legs, the hair around your eyes grows, and falls out from time to time.

I'm sure you have had an eyelash in your eye at least once! Some people suggest you should make a wish on a fallen eyelash. New hairs grow to replace the one that have fallen out. If you look closely at your eyelashes with a magnifying glass (or even better someone else's) you will notice that not all the eyelashes are the same length. There are short one still growing, and long ones getting closer to falling out.

Eyebrow hair grows quite slowly compared to head hair, but they do grow. Many women remove their eyebrows in pursuit of beauty, and then paint on where they think the eyebrow should be (a thin dark line) Once you start waxing or plucking your eyebrows you have to keep doing it every week or so, or they grow back as a dark shadow, which usually looks worse than the original eyebrow.

Nigel Skelton Lab Technician Barkly College - Secondary Tennant Creek NT AUSTRALIA


Click here to return to the General Topics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory