Hormones called androgens, which are present in both sexes, stimulate body hair (known as vellus hair) to darken and coarsen. Men have higher levels of androgens than women, so their body hair tends to be more prolific.
In men, genetics is the most common cause of a hairy back. Certain genes can make men more sensitive to the effects of testosterone, the male hormone that encourages growth of body hair. This can make back hair more present and thicker.
Like so many things, it comes down to a mixture of genetics and hormones. We know that at least some of the genes for hairiness are carried on the X chromosome – and the way these genes are expressed varies between different men and ethnic groups – but hairiness also correlates with high testosterone levels.
Hirsutism is excess hair growth on the body or face. For women, the hair may grow in areas where men often have a lot of hair, but women often don't. This includes the upper lip, chin, chest, and back. It's caused by an excess of male hormones called androgens.
Empirical studies, however, do not support the hypothesis that hairy males are more masculine in biological sense. For example, hairiness has not been found to correlate with traits that are associated with high testosterone levels like masculinity of voice or masculine body shape (e.g., Collins 2000).
A Hairy Chest Might Mean You're More Intelligent
Although the research is dated, another study found that a majority of members of Mensa, or the genius club, had thick chest hair as well. It's not completely clear why hairy men seem to be more intelligent on the whole. And it's entirely possible this is a coincidence.
What Percentage Of Guys Have Chest Hair? A study of over 1100 men ages 17 - 71 found that only 6% had no chest hair at all, while 56% displayed a moderate amount of chest hair. 38% of men displayed a light amount of chest hair.
According to Personal Health via the New York Times, Caucasians are the hairiest ethnic group, with Semitic and Mediterranean people being the hairiest out of all Caucasians.
As we age, our prolonged exposure to testosterone starts to play a visible role on other body hair as well. Just like it transforms the vellus hair on a young man's face into a thick beard, it also changes the nearly invisible hair that grows in places like our ears into thicker strands.
But the evolutionary reasons why hairiness varies with ethnicity are unclear. Caucasian people are generally hairier than the Japanese, for example, even though testosterone levels are the same. The difference seems to be in how sensitive the hair follicles are to those testosterone levels.
Some Women Like it Hairy….
According to the survey, some women actually prefer hairier male bodies than bare male bodies. They feel as though hairlessness on men looks prepubescent and unnatural. The survey also suggests that women prefer male facial hair and body hair because it also makes them appear older and wiser.
Let us tell you this again, 77% of women prefer a well groomed man over a hairy neanderthal ape and yet, (are you sitting comfortably) 58% of you aren't trimming one single solitary hair off your bodies! Now we admit that we're not relationship experts but come on, even we can see the problem here.
PROTECTION AGAINST THE SUN: People who have a hairy body are less prone to sunburn and rashes. Another purpose that they serve is to keep us warm. This process goes like this- when we feel cold, our body hair stands on end and trap warm air which is closer to the surface of the skin.
Too much testosterone can cause symptoms that effect a woman's physical appearance including: excess body hair, specifically facial hair.
A hairy chest signals higher intelligence in a man, somewhat tongue-in-cheek research finds. Dr Aikarakudy Alias, a psychiatrist, has found that hairy chests are more frequent among men who are highly educated, such as doctors.
Many hair follicles stop producing new hairs. Men may start showing signs of baldness by the time they are 30 years old. Many men are nearly bald by age 60.
Sex: Male hair grows faster than female hair. Age: Hair grows fastest between the ages of 15 and 30, before slowing down. Some follicles stop working altogether as people get older. This is why some people get thinner hair or go bald.
The development of chest hair begins normally during late puberty. It can also start later, between the age of 20 and 30, so that many men in their twenties have not yet reached their full chest hair development. The growth continues subsequently. In older adult years androgens cause thickening of the hair.
Certain races have higher rates of hair loss compared to others. Caucasians have the highest rates out of all the ethnic groups. On the opposite end of the spectrum, Native American Indians, Inuits, and Chinese have the lowest rates.
In general, however, the highest rates of male pattern baldness are found among Caucasian men. The second highest rates belong to Afro-Caribbeans. Native Americans, on the other hand, do not struggle much with male pattern baldness. As mentioned, pattern baldness is genetic, that is, hereditary.
What race grows the best beard? 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.
Empirical studies, however, do not support the hypothesis that hairy males are more masculine in biological sense. For example, hairiness has not been found to correlate with traits that are associated with high testosterone levels like masculinity of voice or masculine body shape (e.g., Collins 2000).
Bald men are no more virile and they don't have higher testosterone levels, though they do tend to have hairier arms, legs and chests. Perhaps most surprisingly, bald men don't actually have any fewer hairs on their heads.
83% of Men Trim Their Body Hair—Here's What They're Trimming.