Asian hair
It grows perpendicularly to the scalp. This hair type has the fastest growth rate at approximately 1.4 centimeters per month. A strand of Asian hair has a somewhat round, even shape. Nonetheless, Asian hair has the lowest density of the three ethnicities.
A 2005 study in the journal International Journal of Dermatology also found a difference among races in the rate of hair growth. For example, Asian hair grows the fastest, while African hair grows the slowest.
Caucasians have the highest hair density among the ethnicities studied. Black people have the lowest. Asian people have hair density that falls somewhere in between.
You see, the women of the Red Yao tribe have some of the longest hair in the world – as in their hair is almost the same length as their height!
Compared to silkier hair African-American hair contains more lipids, or fats, but the lipids are less bonded which is why the hair loves oils so much. Along with that, the follicle size is much thicker and it has a flattened elliptical cross section causing it to be curlier than other hair types.
Ethnicity
Your race can have an effect on your facial hair growth. People from Mediterranean countries tend to be able to grow thick beards compared to people from other regions. According to a 2016 study , Chinese men generally have less facial hair growth than Caucasian men.
The least hairy peoples are Asians and American Indians. Finally, within ethnic groups, there are familial tendencies to produce more or less hair; if your parents had a great deal of body hair, you may also, even in the absence of any abnormality.
Black hair is most common in Asia and Africa. Though this characteristic can also be seen in people of Southern Europe it is less common. People of Celtic heritage in Ireland with such traits are sometimes known as the "Black Irish".
Follicles that are more oval in shape cause curlier hair to grow. Very tightly coiled hair is due to the nearly flat, ribbon-like structure of their follicles. This hair texture is very common in people of African ancestry. Not only is African hair often coiled, it also has a unique texture.
Caucasian. Caucasian people have rounder hair follicles, resulting for the most part in straight or wavy hair. Because of this, hair grows out faster and the oil produced at the scalp saturates the length of the hair.
Black Hair Growth Rates
On average, African hair seems to grow about 4 inches per year, while Asian hair grows about 5.8 inches per year. Caucasian hair seems to grow at a rate between these two. Keep in mind that black hair will probably grow anywhere between 4 to 6 inches per year.
Many Asians have naturally straight hair, but there is a significant group of us who do have naturally curly or wavy hair!
Most people of East Asian descent have thick, straight hair. This corresponds with a SNP (rs3827760) in the EDAR gene which is involved in hair follicle development. The ancestral allele of this SNP is the A-allele. The G-allele is the newly derived allele that leads to the thick, straight hair.
Lots of traits are statistically rare: Left-handedness (just 10 percent of the population!), curly hair (11 percent!), and blond hair (4 percent!), to name a few. But of the more than seven billion people on the planet, only 2 percent can claim to have this one special trait.
Natural red hair is the rarest hair color in the world, only occurring in 1 to 2% of the global population. Since red hair is a recessive genetic trait, it is necessary for both parents to carry the gene, whether or not they themselves are redheaded.
At 1-2% of the population, it is the least common hair color in the world. It is most prominently found in Scotland, Ireland and England. Scotland has the highest proportion of redheads; 13 percent of the population has red hair and approximately 40 percent carries the recessive redhead gene.
The title of rarest hair color/eye color combination belongs to red-haired folks with blue eyes. According to Medical Daily, both blue eyes and red hair are recessive traits, so the likelihood of both traits appearing together is actually pretty slim.
There are around 5,000,000 hair follicles on a human, multiply by 7,000,000,000 for 3.5e16 hairs for the human race. I don't think it's much of a stretch from there to assume that combined with all other haired creatures on earth the number of hairs vastly exceeds even our outrageous grass count.
It reduces friction
Armpit hair prevents skin-to-skin contact when doing certain activities, such as running and walking. The same thing happens with pubic hair, as it reduces friction during sex and other activities.
Pubic hair plays a role in reducing friction during activities such as sexual intercourse. It also plays a role in preventing dirt and pathogens from entering the genitals. A person can safely remove their pubic hair if they wish to, but they do not need to.
How come I've got almost no hair on my face when friends my age already have a beard? Getting hair on your face is one of the last changes of puberty. On average, boys start noticing hair on their face around age 15 or 16. Exactly when the changes of puberty occur can vary a lot.
Genetics also affect where facial hair grows and when your beard reaches its full potential. “From ages 18 to 30, most beards continue to develop in thickness and coarseness,” he says. “So if you're 18 and wondering why you don't have a full beard yet, it just may not be time.” Ethnicity can also play a role.
For some unknown reason, this form of hair loss is does not occur among Native Americans. Male pattern baldness runs in the family. If your grandfather, father or brothers went bald early, the chances are that you will too.
Generally, black hair doesn't have to be washed as frequently as other textures of hair because it doesn't retain moisture as much. As a result, most people tend to wash their hair once a week or once every two weeks.