A: Hair grows only 0.3 ~ 0.4 mm every day, and it grows faster during the day than at night. The monthly growth is about 0.9 ~ 1.2 cm, and the fastest growth can reach 1.5 cm. The peak of hair growth is about 20 years old for men and 25 years old for women.

12. What regulates hair growth?

A: Hair growth regulation mainly depends on the blood vessels and neuroendocrine system around hair follicles. Different numbers of blood vessels extend into the hair bulb at the base or nipple of each normal hair follicle, and these blood vessels communicate with branches around the lower part of the hair follicle to form a capillary network towards the nipple, while the capillary network under the nipple on both sides of the hair follicle and the capillary network in the connective tissue layer of the hair follicle form a rich vascular plexus, and blood provides material nutrition for hair growth through these vascular networks and vascular plexus. The growth of hair depends not only on the blood circulation around the hair follicle to supply nutrition, but also on the control and regulation of nerves and endocrine. Endocrine has obvious influence on hair, and androgen can promote hair follicle sheath to some extent. Endocrine includes pituitary gland, gonad, thyroid gland and adrenal gland.

29. Hair growth is closely related to hormones.

Many hormones in the human body will affect the growth of hair. For example, the growth hormone secreted by pituitary gland can promote the growth of hair, and the lack of growth hormone will make the growth rate of hair relatively slow down. Androgen and estrogen are the main factors to control hair growth. They have specific stimulating or inhibiting effects on hair growth in different parts of the body. Sex hormones can also affect hair fitness. Estrogen makes hair soft and shiny, while androgen makes hair hard and thick. Once the sex hormones in the body are out of balance, hair abnormalities may occur. The amount of thyroxine secretion is also related to the quality of hair. Hair is fine and soft when hyperthyroidism occurs, and dry and dull when hypothyroidism occurs. Among these hormones, androgen has the greatest influence on male hair growth. Androgen can promote the growth of hair in all parts of the male body, but it is an exception for hair. Too much androgen in young men will inhibit the metabolism of hair follicles and often lead to hair loss. We usually call it premature alopecia, and medically call it male alopecia or male alopecia. For this kind of alopecia, it is often not effective to stimulate hair follicles with external drugs alone, and only oral antiandrogen such as Shouwu Yanshou (Shengfa) tablets will be effective. Facts have also proved that antiandrogen drugs have the best effect in preventing premature hair loss.

30. comb your hair correctly

Combing your hair can not only clean your scalp, but also massage your head. Combs must be clean and cleaned frequently. The teeth and seams of the comb should not be too thin or too dense. It's too thin to straighten your hair, and dandruff easily leaks through the net. If it is too dense, you will comb it hard and break your hair easily. Don't use the grate head, the grate teeth are too dense and often lose hair because of involvement. Plastic combs are prone to electrostatic reactions when combing their hair. It is best to use a wooden comb, and boxwood comb is the best. Comb your hair in the morning and evening for 5 ~ 10 minutes each time.

There is a way to comb your hair with your fingers, which can massage your scalp, make your blood flow smooth, and prevent hair loss and white hair. The method is to comb your hair from front to back with your hands and fingers after exercise or practice every morning, noon and evening. Move slowly and gently, while combing your hair and rubbing your scalp for about 65,438+00 minutes at a time.

The correct method of combing hair can be divided into three stages: combing the tail knot; Comb the middle section to the end of the hair; Gently stimulate the scalp from the hair root and comb it to the hair tip. Comb your hair gently, don't pull hard. For hair that is particularly difficult to comb, you can spray some comb oil or conditioner first.

Hair is pulled in the direction perpendicular to the scalp, the hair on the top and back of the head is combed up, and the hair on the left and right sides is combed left and right. Dirty hair that is difficult to comb must be combed from the tip of the hair and then moved to the root of the hair, and must not be combed from the root of the hair to avoid damaging the hair. If you comb your hair with a hair brush, you should touch the scalp and push it up slowly in a roundabout way, so that the combed hair will be elastic. If you comb only the surface of your hair, you will comb the dust in it. Comb your hair slowly one by one, don't pull it hastily.

The brush head is similar to the comb hair, but the brush head has stronger benign stimulation and dandruff removal ability to the scalp. It can also flatten hair, promote scalp blood circulation, improve hair follicle nutrition and make sebum secretion uniform, thus promoting healthy hair growth. The method is to brush the hair back and forth, up and down repeatedly, until the hair is brushed smoothly. The hair brushed in this way is elastic and shiny. Brush it dozens of times in the morning and evening. It is best to use a soft and elastic plastic (nylon) brush instead of a hard brush.

Women should not tie their hair too tightly after combing it in the morning, so as to avoid hair loss caused by oppression and pulling on the hair roots. Take off your hair clips and relax your long hair when you sleep at night. If you wear a hat or scarf, don't be too tight.

32. Hair care knowledge

The purpose of hair care is to maintain the health of hair, and at the same time to overcome dandruff or hair loss. The basic methods of hair care mainly include the following aspects:

Shampooing: Cleanliness of hair is the foundation of hair quality health, and correct shampooing method is an important factor in maintaining hair. Wash your hair in time According to the hair quality, the sebum secretion of dry hair is less, and the shampoo cycle can be slightly longer, usually once every 7 ~ 10 day. Oily hair has more sebum secretion and a slightly shorter shampoo cycle. Usually wash once every 3 to 5 days. The sebum secretion of neutral hair is moderate, and it is usually washed once every 5 to 7 days. Shampoo should be carried out in time according to seasonal changes. Sebum secretion is less in winter and spring, mostly indoors, so the shampoo cycle is slightly longer. In summer, sweat glands and sebaceous glands secrete vigorously, and the shampoo cycle should be short. In autumn, the wind is dry, the hair is easy to itch, and the shampoo cycle is slightly shorter. Choose shampoo products according to hair quality, choose mild and nutritious shampoo and hair care products for dry hair, and choose shampoo products with stronger detergency for oily hair. The correct shampoo method also plays an important role in hair care, mainly including the following steps:

Comb your hair, wash your hair with water, wash your hair with shampoo, use conditioner and dry your hair with a dry towel.

Hair care: dry hair and damaged hair should be moisturized 1 time per week to supplement hair oil and moisture. Massage the head for 10 ~ 15 minutes every day to promote blood circulation, supply epidermal nutrition and promote the secretion of sebaceous glands and sweat glands. Use a small amount of olive oil after shampooing. Neutral hair oil 10 ~ 15 times, massage the head 3 ~ 4 times a week, each time 10 ~ 15 minutes, and use a small amount of hair cream after shampooing.

Trimming hair: When the hair grows to a certain length, the ends of the hair will split and break easily. Regular pruning can avoid this phenomenon and keep your hair healthy and shiny. At the same time, regular pruning can also stimulate the metabolism of hair cells and stimulate hair growth.

Fluffy hair: Hair is an appendage of the skin. If it sticks to the scalp, it will affect the breathing and excretion of the skin and cause pathological phenomena of the scalp and hair.

Beware of perming: Perming too often will damage the keratinocytes of hair, making it unrepairable, making hair dry, inelastic and even split and broken. It is advisable to have a perm once every six months, and choose a curling iron core with a slightly larger diameter. The perm time should not be too long.

Reasonable diet: hair is made up of cells, and the metabolism of cells needs a variety of nutrients. Therefore, a reasonable diet is an important factor in supplying hair nutrition. Protein, carbohydrate, fat, vitamins and minerals are the nutritional sources of healthy hair.

33, scientific hair care

If you want to own a hair salon, you should not only pay attention to partial eclipse in your daily diet, but also eat more animal and plant foods containing various nutrients needed by your hair, and you should also know how to care for your hair scientifically. For example, use shampoo when washing your hair. You can't use other alkaline washing products, and you can't directly pour shampoo on your head to wipe it clean, which will damage the hair that comes into direct contact with shampoo. The correct way is to pour the shampoo into the palm of your hand and spread it evenly and thinly on your hair. After wiping, be sure to wash it with clear water and rinse your hair. When perming and arranging hair, we should pay special attention not to let the hair bear the stagnant heat temperature above 80 degrees Celsius. The flowing temperature during blowing shall not exceed 120℃. Because it exceeds the temperature, the fibrous keratin that constitutes the hair will be denatured, which will make the hair swell and break, and the scales will fall off, thus changing color, breaking, weakening elasticity and losing luster. To this end, it is best to choose a cold perm for a perm. Using some hair care products at ordinary times can also help the hair absorb beneficial moisturizing substances and keep the original color of the hair.

34. How to keep your hair healthy

To keep your hair healthy, you must pay attention to the following aspects:

Maintain a balanced diet;

A healthy diet should be foods rich in vitamins and minerals but low in saturated fatty acids, such as green vegetables and fruits, and fish, poultry, lean pork, beef and mutton with high content in protein. Modern nutritionists have proved that the lack of iron, copper and other minerals will lead to premature whitening of hair, so we should eat more animal liver, egg yolk, black sesame seeds, walnuts, soybeans and so on. Excessive alopecia should be supplemented with trace elements such as protein, calcium, iron and sulfur, such as black beans, eggs, milk and black sesame seeds. In addition, eating too much sweets and fat will cause the blood in the body to be acidic, leading to dry and yellow hair. Eating more fresh vegetables and fruits is one of the effective ways to protect hair.

Take part in sports and keep exercising;

This is the key to keeping fit and protecting hair. Because regular exercise is one of the best ways to eliminate tension, and tension is an important cause of bad hair.

Wash your hair in the right way:

Shampooing is not only to clean hair, but also an important way to protect it. But shampoo must follow the scientific shampoo method, otherwise it will damage the hair.

Insist on massage:

Massage is a very important way to maintain hair. Massage is to gently rub your fingers on your scalp. According to the direction of scalp blood flowing naturally to the heart, it is carried out in the order of forehead, hairline, temple, head and neck and hairline of the back of the head. Massage can promote oil secretion, therefore, oily hair massage should be light and dry hair slightly heavier.

Protect against sun exposure:

Excessive sun exposure will make your hair dry and yellow. It is best to take a straw hat or an umbrella when you go out in summer. If you want to swim by the sea, you should pay more attention to protecting your hair, because the salt in the sea water is your hair's enemy. If the hair contains salt, it will absorb the ultraviolet rays from the sun, which will increase the damage of the hair several times. The prevention method is: apply proper amount of hair oil to protect the hair in advance, and wear a waterproof swimming cap. Be sure to rinse your hair after swimming.

Avoid damaging hair:

Improper handling of hair can cause potential harm. Dyeing hair, perming hair, curling hair or straightening hair should be done seriously as required. Only those with good hair condition are suitable for perming, and perming should be at least three months apart, preferably more than half a year. Because perming medicine is harmful to hair, frequent use will make hair lose luster and elasticity, and even turn yellow and dry. When choosing a hairstyle, try to choose a hairstyle with big flowers and few flowers, so that there will be no obvious difference between new straight hair and perm curly hair, and the original hairstyle can be maintained for a long time by doing and blowing. If you choose a hairstyle with many flowers and small pieces, when the new hair grows out, it will be in sharp contrast with the perm, destroying the original hairstyle, and it is difficult to achieve the original effect only by doing and blowing.

Don't use additives casually, choose hair care cosmetics carefully;

If you don't know the performance of hair care cosmetics, don't use them casually, or you will hurt your hair. Consult a professional beautician before use.

35, how to protect the scalp

Scalp has a special position in the skin. It protects the skull and the brain inside it. The scalp also provides a foothold for the hair. Conversely, hair can protect the scalp and skull. The protection of scalp hair is more complicated and involves more problems than other parts of the skin. Shampooing, combing, cutting, perming and dyeing are all important. The choice and use of hair oil, hair fat and shampoo, hair care style and scalp massage are also closely related to scalp and hair protection. The protection of scalp and hair basically includes three links: shampoo-comb-haircut. Of course, the three are mutual infiltration and integration.

Shampoo is first for cleaning the scalp and hair. Because you constantly stroke your hair and rub your fingers against your scalp when you wash your hair, this mechanical effect can promote scalp blood circulation, which is beneficial to hair growth and health care, and the effect is similar to massage. Combing the hair not only has the function of cleaning and removing dandruff, but also constitutes a benign stimulus to the scalp. Carding and straightening the hair not only meets the aesthetic requirements, but also helps to transport the nutrients in the hair from the root to the tip. Hairdressing not only has obvious beauty effect, but also can promote hair metabolism, cut off old hair and grow new hair. Because washing hair and combing hair are both part of the haircut process. Hairdressing has many functions. In fact, it includes every link of scalp hair cleaning. So we can take washing-combing-grooming as a procedure for scalp and hair protection. If you add a perm and dye your hair, its beauty effect will be more obvious. In order to protect the scalp and hair, pay attention to the following issues when cutting hair:

It is not good to keep your hair too long, but shaving your head is not recommended. Don't forget that hair protects the scalp.

Barber tools should be disinfected, not only to prevent fungal infection and suppurative infection of scalp and hair, but also to prevent some viruses such as hepatitis B virus from invading the tiny wounds that may be left during haircut and causing infection. Hairdressing should be gentle, and skin lesions on the scalp should be avoided, especially pustules, cysts and nodules. If there is a large area of uneven damage or scab and scales on the scalp, you can only cut your hair short with scissors, and you can't push it hard with hair clipper. If the scalp has acute or subacute inflammation, such as erythema, edema, blisters, erosion, exudation, etc., you should not have a haircut.

36, dry hair care

Dry hair is caused by physiological, pathological or human factors, which leads to the loss of necessary oiliness and dullness. True hereditary dry hair is rare, and only 5% people are born with dry hair. This kind of dry hair is usually rough and stiff, and it is often tangled and dull because of curl. Most people's hair is dry because of too much sun exposure and wind drying. Many people mistakenly take measures to reduce the number of shampoos, expecting the naturally secreted scalp oil to gather and moisturize the hair, leading to a large number of dandruff until the sebaceous glands in the hair follicles are blocked, resulting in drier hair. When it is proved to be dry hair, the correct treatment methods are: adjusting diet, eating more foods rich in oil, eating more vegetables and raw fruits, and limiting salt intake; Wash your hair at the right time and insist on using the appropriate conditioner after each shampoo; When going out, use sunscreen to prevent the sun from damaging your hair.