Anti-lost, accessible by elevator
Safety Island newspaperman Liu Yadong A
Source: Institute of Physics, Chinese Academy of Sciences
Author: Eric who feels bald
In fact, Xiaobian found out very early that every shampoo would be accompanied by hair loss, but at that time, he was still young, and there was no so-called baldness, so he didn't care.
However, when washing my hair recently, I can clearly feel some hair sliding over my cheeks and floating to the ground under the action of gravity... After washing, facing the bathroom floor, Xiaobian fell into contemplation...
Swipe left to view the real picture >>>
Dude, is this going to be balding rhythm?!
Slowly, as a rational person who has been cultivating physics for a long time, you must be calm when facing problems.
As the saying goes, know yourself and know the other, and never lose a battle. Only with in-depth understanding can we make the most correct judgment and formulate the best strategy.
So today, let's get closer to the world of hair that makes our contemporaries feel anxious...
01 What you may not know about hair
As we all know, the human body is covered with hair follicles all over the body, as long as the hair follicles are healthy, they can grow hair.
But life always seems to be joking, and the hair we most want to keep, the hair, seems to be the most fragile; and the hair that we don't care so much about or even want to take off, seems to be very strong...
Our hair is only 60-90 microns in diameter, so it looks like a silk to the naked eye, but in fact, the structure of the hair is very complex.
Hair under an electron microscope | Image source: wikipedia
From the electron microscope photo of the hair above, we can see that the surface of the hair is not flat, but is composed of many small scales overlapping, which is what we often call hair scales.
If you cut it from the middle and look at the section of the hair, you will find that its internal structure is very layered.
Hair structure profile view | Image source: wikipedia
The outermost epidermal layer (or stratum corneum), which accounts for about 10-13% of the volume of the hair, is formed by flat cells stacked in 6-12 layers in a scaly pattern, which mainly protects the hair.
Inside is the cortical layer, which accounts for about 77-80% of the volume of the hair, and its cellular structure contains a large number of rod-like keratin bundles, each of which is interwoven with several spiral proteins.
The innermost layer is the medullary layer, which accounts for about 5% of the volume of the hair, and is a tubular structure, which is a multi-beehive tissue composed of transparent polygonal fibers.
Hair root follicle profile | Image source: wikipedia
The hair is rooted in the hair follicles, which contain mother cells that produce hair roots, allowing the hair to grow continuously.
Only that part of the hair in the hair follicle is active, and the rest of the part on the outside is not biochemically active (which can be considered "dead").
There are sebaceous glands and hair muscles distributed around the hair follicle, and the oil secreted by the sebaceous glands can play a certain lubrication and protection role on the head.
Hair growth cycle | Source: References[3]
Hair growth is cyclical, the beginning of the 2-6 years of growth period, this stage of hair follicle in the hair cell continues to promote the production of hair roots, and make the hair length continue to lengthen, at this time the hair is relatively stable, not easy to fall out.
At the end of the growth period is a regression period of about 2-3 weeks, which is a transitional phase in which hair begins to move towards "aging".
After the regression period, there is a 2-3 month rest period, at which the hair follicles stop developing, the hair roots begin to loosen, and they are easily shed under external stimulation.
After hair loss, the hair follicles enter the next cycle cycle and grow new hair.
Under normal circumstances, hair in the growth phase should account for 90-95%, less than 1% of the regression period, and 5-10% of the telogen period. So it stands to reason that even healthy hair will have about 100 hairs falling out every day.
Different people's hair may have different traits, the shape is straight and curly, the texture is soft and hard, the degree of oil is oily, dry and so on.
There are many theories that are currently trying to explain why hair produces so many traits. The generally accepted theory among scientists is that the shape of the hair shaft affects the curl of an individual's hair. If the center axis of the hair is closer to the circle, the disulfide bonds present in the hair bundle will be reduced accordingly. This means that the chemical bonds present in the hair bunch are consistent with each other, making it easier to form straight hair.
02 Shampoo use is exquisite
After talking about the hair itself, let's take a look at the shampoo that we often deal with hair.
Probably most of the friends here use shampoo almost every day, but rarely pay attention to the shampoo formula (in fact, Xiaobian is also)
The purpose of our usual hair washing is nothing more than dust removal, oil removal, if necessary, it may need to remove chips, and more advanced maintenance can be done.
So the shampoo is to combine the chemicals that can achieve the above functions, without adverse reactions, so that it can achieve hair cleanliness as much as possible, while protecting the scalp from damage.
Let's first show the ingredient list of a shampoo, let's feel it:
The ingredient list of a brand shampoo | Image source: Taken by myself
Full of organic chemistry to dissuade...
But don't worry, let's take everyone to sort out what these ingredients are playing.
surfactant
Just now we said that the most basic function of shampoo is to remove dust and oil, so surfactants play such a function.
Sodium laureth sulfate (also known as sodium lauryl polyethyl ether sulfate), cocamidopropyl betaine, dimethicone, dimethicone, guar hydroxypropyltrimonium chloride, cocamide MEA and so on in the ingredient list are all surfactants.
Here we should mention two kinds of silicon-containing active agents: dimethicone and dimethicone.
These two substances are called silicone oils, which have the effect of adsorbing on the surface of the hair to form a protective layer, which makes the hair shiny and smooth and easy to comb. However, silicone oil should not be used in excess, otherwise it will clog the hair follicles and be counterproductive.
Dimethicone structure | Image source: wikipedia
Why do you need so many surfactants in a bottle of shampoo? Because a single active agent has limited function, and excessive use can lead to dry scalp and hair.
If a variety of active agents are combined, the dose of each active agent can be reduced, and at the same time, a "combination attack" can be launched, which is more comprehensive in function and less harmful to the scalp hair.
Regulator
The function of the regulator is generally to adjust the pH and viscosity of the liquid, so that the shampoo itself is weakly alkaline and moderately viscous.
However, due to the weak alkaline environment, which destroys the disulfide bonds connected inside the hair keratin, we generally wash our hair with a slightly acidic conditioner to treat it.
Other ingredients
The "other" here actually contains a lot, but because the dose added is not much, it is simply grouped together.
Other ingredients also contain pearlescent agents, moisturizers, fragrances, preservatives, etc., which basically play a role in brightening hair color, making hair not dry, and increasing fragrance as much as possible, prolonging shelf life and so on.
Special ingredients
The special ingredients here vary from shampoo to shampoo, and if you want to increase the anti-dandruff effect, this shampoo like the one above adds piroctone ethanolamine salt. Shampoos like shampoos that require advanced care may also add essences like baked oil.
If the shampoo is used by special people (such as babies), it will reduce the irritating ingredients as much as possible and add milder substances that can achieve similar results.
03 How to solve the problems raised by the title?
Now let's go back to the original starting point, is the hair loss during shampooing a precursor to baldness?
This should be discussed on a case-by-case basis.
Because hair has a growth cycle, it will fall out naturally, and the shampoo contains a variety of chemicals, which is somewhat irritating.
So when the hair in the rest phase meets the irritating shampoo, of course, there is only one ending - falling off. Therefore, it is normal for a small amount of hair loss to occur when washing hair and flushing.
However, if the number of hair losses is large, it is necessary to be vigilant, because this indicates that the proportion of hair follicles in the rest period is beginning to increase, and it is likely to continue to develop into hair follicle atrophy.
In this way, the hair follicle may not be able to start a new cycle from the rest period to the growth period.
It should be noted that there is no particularly perfect treatment plan for hair loss at present, and some so-called shampoos and health care products on the market that help hair growth are likely to be gimmicky than function.
Therefore, Xiaobian feels that it is most important to develop healthy and good living habits to prevent hair loss.
As for those hair loss caused by force majeure factors such as genes and genetics, Xiaobian can only say
Resources
[1] Hair - wikipedia
[2] Price V H. Treatment of hair loss[J]. New England Journal of Medicine, 1999, 341(13): 964-973.
[3] Shampoo - wikipedia
[4] Hamel A F, Meyer J S, Henchey E, et al. Effects of shampoo and water washing on hair cortisol concentrations[J]. Clinica Chimica Acta, 2011, 412(3-4): 382-385.
[5] Hössel P, Dieing R, Nörenberg R, et al. Conditioning polymers in today's shampoo formulations-efficacy, mechanism and test methods[J]. International journal of cosmetic science, 2000, 22(1): 1-10.
Some of the emojis come from the network
Edit: Eric