- You shed more hair in the fall and spring than in summer and
late winter in response to the changes in seasons and daylight
- Asian men have little beard growth and a lower risk of developing
androgenetic alopecia as, on average, they produce less testosterone
- On average, each person has 20 million hair follicles of which
90,000 to 140,000 are scalp hair follicles.
- You can lose up to 25% of your scalp hair before it becomes
- Typically, scalp hair fibers grow for two to seven years before
being replaced by a new hair fiber.
- On average, healthy adult scalp hair fibers grow at 0.35mm per
- Eyelashes are the slowest growing hair fibers at less than 0.16mm
- Chin hairs on young adult males are the fastest growing hair
fibers at up to 0.42mm per day.
- Women have a faster rate of hair growth on their scalps compared
to men by about 0.02mm more per day.
- The world's most expensive shampoo is arguably Alterna shampoo
which contains caviar and costs $200 a bottle. Alterna is a favorite
of the rich and famous and claims to have age-defying properties.
- Rate of hair growth declines with age. As a child, scalp hair
grows at up to 0.41mm per day, but that drops to 0.32mm per day
in old age.
- Over $1.6 billion is spent in the US each year on treating hair
- Hair fiber is as strong as copper wire of the same diameter.
It has a tensile strength of around 1.6 x10-9 N / m2 (one point
6 times ten to the power minus nine newtons per meter square of
hair cross section diameter).
- Up to $180 million of minoxidil is sold each year.
- Over 70 million people in the US have some degree of androgenetic
- Normally, dry hair can be stretched one-fifth of it's length
before breaking. Wet hair can stretch between 40-50% of it's length.
- On the scalp there is an average of 1,000 hairs per square
inch or about 250 hair fibers per square centimeter.
- People without alopecia may lose up to 100 scalp hairs a day
as a result of normal hair cycling.
- The fine, downy hair that covers the cheeks and other parts
of the face is called lanugo hair. The hair on your scalp and
any other body hair that is pigmented is called terminal hair.
- The numbers of hairs on the head vary with the hair's natural
color. Redheads have about 90,000. Black, 108,000, while brown
and blonde haired people have up to 140,000. The number of scalp
hairs changes with ethnicity too. Far east Asians have as few
as 80,000 scalp hair follicles.
- In terms of raw elements, on average, hair is composed of 50.65%
carbon, 20.85% oxygen, 17.14% nitrogen, 6.36% hydrogen, and 5.0%
sulfur. Hair also contains trace amounts of magnesium, arsenic,
iron, chromium and other metals and minerals.
- Darker hair contains higher levels of carbon than blonde hair.
- Between 65% and 95% of hair fiber is made of proteins called
keratins. Keratins are made from amino acids and in hair keratins
the predominant amino acid is cysteine.
- One keratin protein molecule measures 10 nanometers across.
10,000 keratin protein molecules lying side by side cover the
width of one human hair. So the cross section of one human hair
can contain up to 78,000,000 keratin proteins.
- The average anchoring strength for a chest hair is 70 grams.
That is, you can add 70 grams of weight to one chest hair before
- Beards of men contain between 7,000 and 15,000 hairs.
- Men remove 8.4 meters of face stubble in their lifetime. It
takes them approximately 3,400 hours to do so.
- Because hair is so strong you could hang between 5,600kg and
8,400kg from one head of hair without it breaking (although your
neck would not take it !).
- As a rough quide, 20% of men in their 20s have pattern baldness,
30% in their 30s, 40% in their 40s, and 50% have pattern baldness
in their 50s. If you get to age 60 without developing pattern
baldness you will probably avoid it alltogether.
- By age 50, 20% of women have thinning hair.
- Our eyebrows contain 550 hairs, give or take a few.
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