- BBC News World
Hair is an important part of who we are, and our efforts to keep it clean and clean have created an estimated $80 billion hair care industry.
This industry offers us many products that they say are created to keep our hair looking healthier, shinier, and healthier.
But what is healthy hair? Hair, whether it’s straight, curly, long or short, isn’t just a dead protein?
Hair is a strand of cylindrical structure that grows on the human scalp and is divided into two parts: an inner part consisting of the root and the follicle and an outer part, which is the rod-shaped hair, which is the visible hair itself.
“Threads are not really living matter,” Dr Sharon Wong, a dermatologist who specializes in disorders of the hair and scalp, told the BBC’s Crowdscience programme.
“Technically, we have the live part, which is the follicle, and then we basically have the dead part, which is the fibers that come out of the scalp, and that’s what matters most to us.”
A hair follicle is a tube-like depression in the scalp that surrounds the root, where hair growth begins.
Each hair has its own follicles, which differ in depth.
“Every hair follicle on our body – we have about five million – undergoes a hair growth cycle which is a process independent of its neighbour,” the expert explains.
“That’s why humans don’t have simultaneous hair growth. As humans, we don’t shed our hair seasonally at the same time.”
L’une des choses vraiment surprenantes à propos du corps humain, dit l’expert, est le fait que le follicule a cette capacité de continuer à se régénérer de sorte qu’à chaque fois qu’un cheveu tombe natureest relacement, il é else.
If we enlarge the thread, we will see that it is a tubular structure, the lower part of which is the hair follicle bulb, which is called the dermal papilla.
At the top of the hair follicle are pockets of stem cells that send daughter cells to the bottom or root of the follicle and that will periodically tell the follicle to release the filament.
“We all have a genetically predetermined duration of this hair growth cycle which can range from two to about seven years,” says Dr. Wong.
“This is why some people can only grow their hair on their shoulders and others can grow it on the floor.”
But once the growth phase or anagen phase is over, the hair follicle enters a kind of stopping phase where the strands simply stop appearing.
Then it enters the resting phase or telogen, where the hair begins to fall out and the growth phase begins again.
What is healthy hair?
But even though hair isn’t a living structure biologically, that doesn’t mean there’s no difference between healthy hair and unhealthy hair, notes dermatologist Sharon Wong.
“If you look at an intact strand under a microscope, you can see that the outer layer, which is the cuticle, looks like a well-straightened, smooth, flat weave of hair. It’s a protective layer on your hair, against things like heat and chemicals.”
“Because over time, with excessive exposure to UV rays or other factors, the skin gets damaged and when you look at a damaged strand, you see skin that doesn’t look flat and clean, like it has scales.”
Damaged skin also makes the strand more porous, which means chemicals, heat, and damage can reach the center of the hair and weaken it from the inside out.
This can be seen at the ends of split hair, or when the hair becomes more brittle and brittle or loses its colour.
So what should we do to keep the hair structure healthy? Should we stop using hair dryers and straighteners, we asked Dr. Wong.
“It’s actually more about how hot these appliances are and how often you use them,” she says.
“For example, if you’re using a hair straightener to straighten hair, it’s better if the heat is less than 180 degrees because then you really start to spoil or damage the proteins, and remember that your hair has 90% protein.”
“But if you use it two or three times a week and do it continuously, it becomes cumulative damage and then your hair becomes more brittle.”
For shampoo and conditioner, how often should they be used?
“The purpose of the shampoo is to clean the scalp and make sure there is a firm base for healthy hair growth,” the dermatologist explains.
The conditioner is intended for the hair strand itself, to nourish it and prevent the hair from drying out.
“When it comes to how often you wash your hair, there is no one-size-fits-all solution, it mainly comes down to the cleanliness of your scalp and whether you have a particular disorder that affects it.
“If you are someone with a very oily and very oily scalp, you may need to wash your hair daily. And if your scalp is very dry, daily washing may not help.”
The ideal option is to know what is best for everyone’s scalp, as determined by a dermatologist.
“It also depends on your lifestyle, or if you use a lot of hair products, so I recommend washing it at the end of the day,” she adds.