How Fast Does Hair Grow: Stages and Factors

Hair is the thin thread-like structures/outgrowth or pigmented filaments of the epidermis of mammals. In humans, hairs are mostly covering of head but also arise on other parts of the body, including hands, arms, and legs.

Hair follicles are the structure from which hair grows. Approximately 5 million hair follicles are present on our body and 100,000 just over the head. On average hair growth is about 0.5-0.7 inches per month. This is according to the research of the American Academy of dermatology and The Trichological Society.

Many different factors from age to food, and genetics affect hair growth. With age, follicles stop producing hairs- hair thinning, loss, or baldness occurs.

Does Water Intake affect hair growth?

Hairs are directly affected by water intake. Normally humans need about 2-3 liter of water per day for hair to grow but if you take minimum water, then hair loses its shine and becomes dry and rough. Dehydration will seriously affect the hair growth causing split ends and damage thus inhibiting growth. So try to maintain your proper and required water intake for better hair growth. Although there is no substitute for water, you can also take some fresh juices for the supply of minerals to hairs.

Stages for Hair Growth

Hair growth occurs in 4 major phases, each phase has its own activities and timeline. Hair follicles also affect the shape of the hair. If you have round follicles, hairs will be straight while hairs will be curly if the follicles are ovals.

Following are the stages of hair growth.


The anagen stage is commonly known as the hair growth phase. About 85-90% of hairs on the head are in the anagen phase. Hair follicles have root hair that contains proteins. When the proteins get the oxygen, they divide and multiply to form a hair. As the hair grows and elongates, it comes out to the skin by passing through lubricant glands that provide oil to the hair. The hair coming out of the skin is dead, and the oil keeps it soft and shiny.  In the anagen phase, hair grows about 1 cm per month and can last from 2 to 8 years. The more the hair stays in this phase, the more it will be long and healthy.


After the anagen phase, the transitional or catagen phase starts. In this phase, the hair follicles renew themselves and thus the growth ceases for some time. This phase lasts for about two weeks, hair follicles shrinks and hair stops to grow. Blood supply to the hair is cut off and a new hair club is formed.


It is also known as the shedding phase or resting phase in which hair falls. Ten to fifteen percent of the hair on anybody’s head is in the telogen phase. The hair will be lost its connection from the root and will shed off.  It normally lasts for 3 months in which hair growth is dormant.


Now the whole process of hair growth begins again, and each hair follicle independently passes through all these phases. If the process of hair growth is not independent, your all hair will be lost. A healthy head loses only 50 to 100 hairs per day normally. Dr. Scott says, “It might be normal for a person to shed 150 hairs a day”.

Factors Affecting Hair Growth

As everyone has a different hair type and growth cycle, different factors affect the growth of hair in several ways.


Genetics is a major factor influencing the thickness, length, and pattern of hair growth. There are different genetic syndromes in which the mutation of genes occurs and the texture of hair gets affected. Autosomal recessive hypotrichosis syndrome and monilethrix syndrome influence hair texture and growth. In females, the most common genetic cause of hair loss is Androgenic Alopecia or female pattern baldness. When the woman is at the age of 40, her front part of the scalp loses hair and hair grows very slowly.


With the age, it is natural for hair to become thin and growth ceases. Hair texture, color, size, thickness, and location changes with the age. You can easily observe hair aging signs with time and age. The normal growth period for hair is from 15 to 20, and after that hair follicles start aging. After 30, graying of hair is also a common condition. At the onset of menopause-40 years, hairs become thin or baldness can also occur. Also, eyebrows grow at a very lower rate at this age. Hair follicles stop working and then you can observe many problems of hair growth.


Gender plays a great role in determining the rate at which hair grows. Men’s hair grows faster than a woman’s but the man faces baldness in the early ages than women’s. Excessive hair thinning occurs for 40% of the woman by the age of 40 and 60% of men by age 50.  A study of 59,765 anagen hairs revealed that thinner hair grows slower than thicker hairs. Hair loss is believed to cause by testosterone, as males have higher testosterone levels, so it can lead to baldness in males. While females have a low quantity of testosterone, normally hair thinning occurs in women’s.


A proper and healthy diet is necessary to maintain the natural growth rate of hairs. A healthy diet becomes more important in conditions where hair demands more nutrition. Like after the child’s birth or during menopause condition.

If your diet is not proper and hair doesn’t get essential minerals and nutrients, there is a greater risk for hair to fall or thin. Iron deficiency is a leading cause of hair fall in both men and women. Vitamins A, D, E, Zinc, Selenium, biotin, and amino acids and proteins are the supplements that must be provided to hairs for natural growth. Naturally, a diet with fruits, vegetables, meat, and fish can mark up the deficiency of these supplements.


Stress, tension, or depression are the factors affecting hair growth, regardless of gender. Depression causes the hair to become dry and break easily. In rare cases, anxiety can also cause hair loss, but not predominantly. Stress causes the hair follicles to become dormant during unfavorable conditions. The hair cycle is stopped and hair ceases to grow rather than shedding. When the stress level diminishes the hair follicles again start producing hairs. In short, stress is a big trigger of hair loss. When the body is put through extreme stress like in childbirth, telogen effluvium-serious hair loss condition develops.

Medical History

Harvard research shows that medical history or illness can also cause hair loss. If you have previously any medical history or diseases like Thyroid diseases, hormonal imbalance, or any other nutritional deficiencies, you are likely at a greater risk of hair fall. It is also observed that medication or some drugs also cause shedding of hairs. Interesting to know is the intake of supplements can also cause hair fall if they were used without need. It is difficult to point out the exact drugs that cause hair loss, any drug in any person can give the reaction. Like in some people, aspirin lowers hemoglobin level, thus aiding hair fall.

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