How hair grows and what determines the growth rate

We frequently take hair growth for granted, but have you ever wondered how it really occurs? The process is surprisingly intricate, spanning from the instant a hair strand appears on the skin’s surface to the phases it goes through before falling out.

Our hair grows at different rates depending on a variety of factors. Factors such as age, genetics, and health habits are all relevant. We can better care for our hair and control expectations if we are aware of the factors that affect hair growth.

Understanding the fundamentals of hair growth is essential, whether your goal is to grow out your hair or you’re just interested in learning more about how it all goes. Let’s examine the specifics of hair growth and the factors that affect it.

Hair structure

Hair on the head has a slightly different structure than hair on other body parts. No matter where the hair is located, it always consists of:

• protein;
• water;
• lipids;
• pigment.

Protein makes up 78% of hair shafts, while pigment makes up only 1%. The following components can be distinguished if we discuss the physiological structure rather than the chemical:

• rod;
• bulb or hair follicle.

There are three layers in the hair shaft:

• cuticle – these are keratinized particles that, adjoining each other, form an overlap similar to tiles. Outer layer. Responsible for elasticity, degree of porosity, strength;

• cortex – the main part, consisting of hard keratin – a protein that determines the quality of hair, its strength, shine, health;
• medulla – an internal substance saturated with air. It is the medulla that is responsible for the transportation of nutrients.

Additionally, the bulb—the root from which hair grows—has a unique structure. The hair papilla, which is located inside the bulb, is what supplies the nutrients.

The steps involved in nutrition are as follows:

1. A useful component that enters the body, for example, calcium, is absorbed into the blood or lymph;
2. Moving through the circulatory system, it is absorbed by different parts of the body that need it. The last "stop" is the hair papilla – useful components are delivered there last.

Little calcium intake means that all of the body’s calcium reserves will be divided among the various bodily regions, and by the time the blood reaches the papilla’s blood vessels, it will be "empty," or devoid of any beneficial components.

How "satiably" the papilla is fed determines the activity of the hair follicle, the thickness of the curls, and the rate of growth. Hair follicles vary in appearance depending on where they are located; the head has the longest, elongated bulbs, while the eyebrows and eyelashes have the shortest ones.

Growth process

There are three stages to the full growth cycle:

• anagen. The longest period, which on the scalp can take several years. Anagen is the origin and formation of a hair in the bulb and its growth beyond the epidermis;
• catagen. Catagen is characterized by the cessation of the activity of the hair papilla. The papilla stops being nourished, after which the final phase begins;
• telogen. The period of sleep, when any processes inside the bulb stop – neither nutrition nor blood circulation occurs during this period. As a result of the "inaction" of the body, the hair shaft dies and falls out.

Hair loss, or the telogen phase, is a typical physiological process. A healthy individual may have between 10% and 15% of their total hair in the dying stage. Meanwhile, 80–90% are in the anagen stage, which is a state of active growth. The fact that adjacent growing hairs can last for varying lengths of time—one for just a few months, and the other for several years—is interesting. Researchers are still unable to determine why there is this difference.

The hair follicle starts the anagen process, or the growth of a new shaft to replace the fallen one, as soon as it enters the telogen phase, when the hair is about to fall out. Over the course of a person’s lifetime, one hair follicle typically goes through the anagen phase thirty times.

What determines the color

The type and amount of the coloring pigment melanin determines the color of a person’s hair strands. The cortex is home to melanin, which builds up there and gives curls their distinct color.

Two varieties of melanin exist:

• eumelanins – have a black and brown color and color the shaft in dark shades – black, brown, dark blond;
• pheomelaninswith a predominantly black and brown color. They are responsible for light shades.

The amount of air bubbles in the medullary and cortex layers determines how saturated the shaft is with color; the lighter the hair.

Natural processes like age, hormones, heredity, and general health all have an impact on hair growth. Every hair strand experiences growth, rest, and shedding cycles. Healthy hair usually grows about half an inch per month, though everyone’s hair grows at a different rate. Your diet, lifestyle, and hair and scalp hygiene all have an effect on how quickly and strongly your hair grows.

Why hair growth slows down

Numerous elements influence the growth rate. The most fundamental ones are:

• age;
• body condition;
• heredity;
• the amount of incoming nutrients.

When a hair follicle gets all the nutrients it needs from the body, it grows by 0.2 to 0.5 mm per day, or 1-2 cm per month.

• up to 30 years the growth process is faster;
• in women, hair grows faster than in men. A healthy woman can grow 15-20 mm per month, and a man only 2-15 mm;
• active growth is observed in spring and autumn, while in summer and winter the process slows down.

Main reasons for slow hair growth

Lack of nutrients

We will talk about which substances are responsible for the quality of hair in the next section, and here we will focus specifically on the process that accompanies the deficiency of useful components. When there is a deficiency of useful components in the body – and the hair receives them last of all, after other systems of the body are nourished, the blood vessels attached to the hair papilla stop nourishing it. Of course, the papilla does not transfer any “usefulness” to the bulb. The longer the deficiency, the worse the hair will look – it will lose its shine, become brittle, growth will slow down, and sometimes even profuse hair loss will begin.

The most frequent reason for issues with curls is an imbalance in the vitamins and microelements.

Internal causes

Exacerbation of chronic diseases or the onset of new ones are examples of internal causes. Additionally, hormonal changes—during pregnancy, for instance—and stress and emotional overload can cause growth slowdown or hair loss.

When the body is experiencing issues, all of its energy is directed toward resolving the unpleasant symptoms; as a result, the nutrition of the hair follicles is neglected. In the end, inadequate blood circulation to the follicles impairs their ability to function.

The majority of the time, gastrointestinal disorders affect curls. Nutrients taken with food or dietary supplements may not be absorbed fully or at all due to stomach issues. This leaves the body lacking in certain areas and prevents any nutrients from reaching the head.

Heredity

If genetics is the cause of slow growth, then the issue manifests in early childhood. Since hereditary disorders are characterized by gene-level failure, they are essentially incurable.

Skin diseases

The normal structure of the scalp is disrupted by dermatitis, lichen, and seborrhea. In addition to disturbed regenerative processes and air exchange, hair shedding is also impeded.

Improper care

In addition to causing slow growth, shampoos, masks, styling tools, and hairdressing procedures can also cause thinning, brittleness, and a loss of shine. In this instance, the hair is exposed to outside factors, which may cause the hair follicles to weaken and the structure of the hair shaft to alter.

Regardless of the reason, slow growth is typically accompanied by other issues. In particular, nail delamination and fragility frequently occur in tandem with slow growth.

How to speed up hair growth

Eliminating the underlying cause of the slowdown should be the first step towards accelerating growth.

• balance your diet, providing your body with all the necessary components. Vitamins A, E, C, as well as almost all B vitamins, including biotin, are important for curls. Important microelements are iron, zinc, manganese, silicon, magnesium and calcium. If you plan to take vitamins and vitamin complexes, first get tested for vitamin levels to confirm a deficiency. Excess vitamins also negatively affect the body. You can get tested without a doctor"s referral in private laboratories;
• make sure that everything is okay with your body. First of all, it is important to check the gastrointestinal tract, as well as the thyroid gland. For consultation and testing, it is enough to contact a therapist, he will issue referrals or redirect you to highly specialized specialists;
• check the skin for skin diseases – this issue is dealt with by a dermatologist or trichologist;
• review your care. Try using mild shampoos or even co-washing, choose products with a safe composition that does not interfere with the work of the follicles and does not have a detrimental effect on the hair shaft.

Other methods, such as treatments and products that alter blood flow and nutrition, can also help you grow hair faster.

Oils, masks, different conditioners, and scrubs are examples of growth products. Because of their composition, these products promote blood flow to the follicle and improve its nutrition. This causes dormant bulbs to awaken and hair to start growing more quickly.

The most popular products for hair growth are:

• oils – burdock, castor, neem, amla;
• masks – with pepper, oils, mustard;
• shampooswith biotin, niacinamide, extracts and oils of plants – rosemary, ginseng, burdock.

Products that consumers have independently modified to address the issue of slow growth are also utilized. Among them is nicotinic acid, which is prescribed to patients to treat and mitigate liver disease, vascular diseases, and diabetes. After washing, the scalp is rubbed with injectable nicotine acid. Consequently, the follicle receives useful components faster and blood flow is enhanced. Please be advised that self-prescribing these medications may have negative effects. You should at least have an allergy test done and see a doctor before using.

How to use procedures to accelerate growth:

• massage. The simplest procedure that can be done even at home is massaging the head. Of course, if possible, it is better to go to a massage therapist, since self-massage is less effective in this case. The mechanism of action of massage, in general, is the same as when using different products – due to stimulation of the scalp, the flow of nutrients to the follicle is accelerated;

• darsonvalization. Darsonvalization is the effect on the scalp with a device that creates low currents. This awakens dormant follicles, accelerates metabolic processes, and also dilates blood vessels. Darsonvalization is still a poorly studied and clinically unproven method of accelerating growth, but it is successfully used all over the world;

• cryomassage – exposure to the skin with liquid nitrogen. Starts the process of cell renewal, accelerates the intake and absorption of useful components;

• mesotherapy – introduction of vitamin cocktails into the shallow layers of the scalp. The advantage of this method is that the useful components go directly to the follicles – almost the entire injected volume is retained in the head.

Hair loss: normal or pathological

As was previously mentioned, losing up to 100 hairs per day on average is normal and does not signify a medical condition. Dead hairs that have reached the end of their life naturally fall out and can also be removed mechanically by washing or combing. After combing, gather the hairs that have fallen out of the comb and count them if it is difficult to count them by eye. Include the fact that 10–20 hairs fell out during the day, particularly if the hairstyle was free-form and relaxed in comparison to the standard.

How to tell if hair is falling out or not growing back:

• Inspect the pillow in the morning. If a significant number of hairs remain on the pillowcase, this is a reason to think or, at least, carefully observe the behavior of the scalp and hair shafts for some time;
• if a lot of hair falls out during washing. Again, a lot is quite subjective, so it is better to evaluate from the position of "was-became", that is, before 10-20 hairs fell out, and now in whole bunches. Please note that hair loss during washing can occur due to a change in shampoo, as well as during sulfate-free care. I have tested on myself that when washing with a sulfate-free product, more hair falls out. There is no scientific explanation for this fact, but in practice many women observe such a reaction of the body. Perhaps this is due to the fact that the scalp has to be massaged more, since without sulfates there is no foam, therefore it is more difficult to clean the scalp and roots – but this is only an assumption;

• a lot of hair remains on the comb. Whole clumps that remain hanging on the teeth are abnormal – if 10-20-30 hairs have fallen out – do not panic. Please note that we are talking about normal, high-quality combs that do not tear hair. Pay attention to wooden combs with "blunt" teeth, as well as combs – they delicately untangle strands without harming the roots.

The frontal area, the temples, and the back of the head will all have bald spots if hair loss has already begun. These symptoms will be more noticeable. Counting the hair after combing is pointless in this situation; instead, get in touch with a trichologist right away and start treatment.

Understanding the reasons behind hair loss can aid in analyzing one’s appearance, diet, and overall health. Hair loss typically results from the same factors that cause growth slowdown:

• lack of vitamins;
• incorrect care;
• diseases of internal organs or skin;
• stress and nervous shocks;
• unstable hormonal background.

While growth can be normalized and some of these conditions are easily treated, others need more intensive care. In any event, seek medical advice as soon as you notice increased hair loss in order to identify and address the issue.

Stages of Hair Growth	Factors Affecting Growth Rate
Anagen (Active growth phase)	Genetics, hormones, and overall health
Catagen (Transition phase)	Age, stress, and nutrition
Telogen (Resting phase)	Hair care routines and environmental factors
Exogen (Shedding phase)	Seasonal changes and medical conditions

Individual differences exist in the natural process of hair growth. Numerous factors, including hormones, age, genetics, and lifestyle choices, affect how quickly or slowly hair grows.

You can take better care of your hair if you understand how it grows. Knowing these specifics, such as the growth cycle and factors that influence it, will help you make well-informed decisions regarding your hair care regimen.

In the end, even though we have no control over how quickly our hair grows, we can help it grow as long as we take good care of our scalp and make healthy decisions.

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