Hair may appear simple in structure, but there’s more to it than meets the eye. Here are six hair facts everyone should know.
1. It’s Strong
Healthy hair can swell up to 20 percent of its diameter, stretch up to one-third of its length, and support up to 12 tons in weight. Weight for weight, it’s as strong as Kevlar, a material used in body armor.
2. It’s Always Shedding
The average head contains 120,000 strands of hair, but up to 100 of these are lost every day. Excessive hair shedding, known as telogen effluvium, is common in people who have experienced sudden or severe stress.
3. It Lasts for Several Years
A single strand of hair can last for up to six years. When it eventually falls out, it’s replaced by a new hair, which grows from the same hair follicle. Each hair follicle follows its own pattern of growth and rest. This means that each hair strand grows independently of the surrounding strands.
4. It Grows at Least 6 Inches a Year
Hair grows on average half an inch a month — that’s 6 inches a year. Although it may appear to grow faster in summer than in winter, hair actually grows at a constant pace throughout the year.
5. It Starts Out White
Hair starts out white and gets its natural color before birth. Its color is determined by the ratios of two pigments, eumelanin, which is dark, and pheomelanin, which is light. People with brown or black hair have more eumelanin than people with blond or red hair.
6. It Goes Gray When It Stops Producing Pigment
Hair goes gray when it stops producing the pigments that give it its color. Most people start going gray in their mid-30s, but some go gray as early as their late teens. While most early graying is genetic, hair that turns gray too soon could signal a health problem such as vitamin B12 deficiency or vitiligo.
Hair is a complex structure that’s still not fully understood. Research to further unravel its mysteries will undoubtedly uncover even more fascinating facts.
