In 1909, a top public health official in America wrote in an academic journal that baldness was caused almost exclusively by snug-fitting hats.

Male pattern baldness is not solely inherited from the maternal side; its causes are still under investigation, but scientists think the genetic component of this type of hair loss involves multiple genes.

Male pattern baldness accounts for more than 95% of hair loss in men and is characterized by thinning hair, hair loss, and a receding hairline.

A man’s genes can predict his hairline

There’s actually some truth to the idea that you should look at your mother’s father. But genetic research tells us that the full picture is somewhat more complicated. An interesting read on how to use genetics to figure out if you'll go bald (with illustrations).

Humans may have as many as 100,000 to 150,000 individual hairs on our scalps, growing at a rate of roughly 1 centimeter per month.

Real-time tracking of individual hair cells has revealed that hairs don't actually get pushed out from the root—instead, hair cells are tugged upward by surrounding tissues that act like tiny motors.

Telogen effluvium is a common, temporary type of hair loss that can be triggered by severe stress, illness, or other body changes like childbirth—it pushes as much as 70% of hair into its resting phase, causing hair to fall out. (Paywall may apply.)

Cleopatra purportedly recommended grinding up fly heads and rubbing them on areas experiencing hair loss as a treatment.

40% of women will have noticeable hair loss by age 50.

Scalp cooling caps may help prevent hair loss during chemotherapy by temporarily reducing blood flow to the scalp, thereby reducing the amount of chemotherapy that reaches hair follicles.

It's been about 30 years since a new hair loss drug was approved in the US, and women currently have no approved pills for hair loss.

Rodent research suggests goose bumps may play a role in hair growth—raising questions about if this knowledge could be used to reactive sympathetic nerves in hair follicles to boost hair growth in people.

The curious history of the Kentucky Derby's hats

The Kentucky Derby is one of the most prestigious horse races in the world, but it's also known for its iconic hats. This Garden and Gun article explores the historical significance of the hats at the Kentucky Derby, which began in 1875. See photos of the famous Derby hats through the years, and learn why they remain a central part of Derby culture to this day.

British beard history, 101

The beard has gone in and out of fashion for centuries in Britain. It was hated in the 18th century but became a must in the 19th. This quick list rehashes 15 fascinating tidbits about the beard, including possible useful functions for them (a beard is equivalent to an SPF 21 sunscreen) and how barbers were often also surgeons.

We're typically born with all the hair follicles we'll ever have, just as women are born with all their eggs.

Humanity's reduced body hair slows down wound healing

Cuts to human skin take twice as long to heal compared to chimps and other mammals. Scientists argue this is due to the reduced number of hair follicles on human bodies. Hair follicles contain stem cells which help repair skin cells faster, so as humanity shed its hair over time, so to speak, it also slowed its wound healing.

Hair loss after childbirth happens because pregnancy hormones paused the normal hair shedding process during pregnancy, so the hair loss is actually your hair cycle 'catching up' with its normal process several months postpartum.

The history of skull modification

The ancient Maya people sometimes modified their skulls to appear more conical. Body modification has been a human pastime for literal ages, from piercings to bindings and everything in between. Modifying one's skull shape may have been a way to symbolize status, beauty, belonging, or belief. The health impacts of such practices are still debated. This article explores the history and health impacts of skull modification, also known as artificial cranial deformation.

Hearing loss is linked with brain volume reductions

The brain looks different as a result of hearing loss, with reductions in brain volume overall and in specific areas, and these changes are hypothesized to impact cognition. Exactly why hearing loss alters cognition is an active area of research, but theories include that the elevated cognitive load of straining to hear affects brain power available for thinking and memory and that hearing loss leads to social isolation which boosts dementia risk.

Mapping hearing loss in the US

Nearly 10% of Americans suffer from some degree of hearing loss, measured as the inability to hear sounds lower than 25 decibels. The incidence of hearing loss increases with age and is typically higher among men. Recent analysis produced a puzzling observation researchers can't quite explain: There's a larger incidence of hearing loss among rural populations than in urban centers. Explore the data with this map and explainer.

Hearing loss can affect balance and make falls more likely

For reasons that are not yet fully understood, hearing loss seems to increase the risk of falls. One explanation is that reduced environmental awareness due to hearing loss may put people at greater risk. Another theory is that the brain has to work harder to process sound with hearing loss and that cognitive load may also boost the chances of falls. One study found that for every 10 decibel increase in hearing loss, there was a 1.4 fold increased odds of falling in the preceding 12 months.

Stress contributes to gray hair because when the body experiences stress, the sympathetic nervous system releases specific hormones that influence pigment-producing cells.

Everything scientists could learn by looking at your skull

Our skulls are all unique, but they also share characteristics across groups of people. In the absence of fingerprints, forensic scientists can learn a lot about you just from your skull.

'Hair' helped redefine Broadway theater

"Hair" rewrote the rule book, bringing politics, race, and, yes, nudity to Broadway. Plenty was going on backstage, too, with the young, revolutionary cast embracing the countercultural life they portrayed onstage.

Age-related hearing loss, known as presbycusis, is a top cause of hearing loss

This video walks through the biology of why presbycusis (prez-buh-kyoo-sis) occurs and its etiology. This type of hearing loss is gradual and typically starts with reductions in the ability to hear high-pitched sounds.

The anatomy of our hair follicles explains goose bumps

The arrector pili muscle contracts when we're cold or scared, causing hairs to stand up and the skin to form the bumps known as goose bumps. This reaction is typically involuntary.

A WWI war helmet outperformed modern gear in this study

Your great-grandparent's World War I helmet stuffed in the back of a closet may be just as effective at preventing brain injury from some blasts as a modern-day military helmet. This article further explains a study that pitted WWI and modern helmets against each other.

Untreated hearing loss is linked with dementia risk

Hearing loss does not cause dementia, but it does increase the risk of developing dementia and research suggests that people who wear hearing aids for age-related hearing loss also maintain better brain function than those who don't.

NHL Commissioner Gary Bettman rejects ties between CTE and playing hockey.

The gaps in menopause research and their effects

Nearly all studies (99%) researching the biology of aging don’t consider menopause in their setup. A Harvard professor noted that about 75% of aging-related diseases are likely influenced by menopause. In this article, she discusses how gaps in research are negatively impacting how the medical system can effectively treat aging women. Read her analysis of the issue here.

History's weirdest weight loss fads, fact-checked

Nothing catches popular attention more than a claim to have found a quick weight-loss technique. History shows us such claims are often unfounded. Dr. Michael Mosley explores extreme weight-loss tips from history, from tapeworms to vinegar diets.

No medical evidence suggests collagen drinks or supplements will improve your hair

Marketing claims that collagen supplements or drinks will make your hair shiny, thick, and improve hair growth are not backed by scientific evidence.

John Riddell’s first helmet was adopted by college football teams in 1939

The early days of football were violent and there was little protection for players, especially their heads. When deaths became commonplace, John Riddell set out to invent a better way to protect football players. Eventually, the technology from Riddell’s helmets ended up on WWII battlefields.

Long-term goose bumps are something to flag to your doctor

Although rarely a cause for concern, persistent goose bumps with no known cause could be a symptom of something to discuss with your doctor, including anxiety, a hair follicle blockage, or conditions that arise from an overreaction of the autonomic nervous system.

NHL players used to not wear helmets or masks

Until the 1970s, hockey goalies didn't wear masks to protect their faces with any regularity. Instead, they took pucks off their cheeks, foreheads, and mouths, resulting in serious scars. Any player who entered the league after June 1, 1979, was required to wear a helmet, but several players who'd started before then chose to continue playing without one.

Age-related macular degeneration is the primary cause of blindness in older Americans.

Experience a century of America's healthcare advances with this medical visualization, tracing a sampling of healthcare innovations from head to toe.

Bow ties became a Bill Nye wardrobe staple after he took part in an athletic banquet

In high school, boys served as waiters during a ceremony where girls would receive awards for gymnastics, lacrosse, and other sporting events. Wanting to fit the role, Nye's father helped him dress like a waiter, and he continued wearing bow ties upon seeing their practicality in the lab.

The impact of gravitational force on our bodies surprised early coaster riders and engineers

There is only a certain amount of gravitational force that the body can handle before dealing with consequences like short-term vision loss or unconsciousness. Increased scientific understanding has largely reduced these impacts, with engineers combining periods of intense pressure with periods of relief.