Beautiful hair and clean, tidy nails are of the utmost importance to everyone. One woman may spend a lot of her time, effort, and money in order to have long, beautiful hair, while another woman who does not spend any of this gets long hair in less time. What is the secret behind that?
The Conversation newspaper published an article examining the reasons that cause differences in the speed of hair growth between one person and another. The newspaper explained that head hair grows on average by one centimeter per month, while nails grow at a rate of just over 3 millimeters, and when left unattended, hair and nails can grow to amazing lengths that can hinder life. Therefore, most people cut their hair and trim their nails periodically and do not let them grow much.
What are hair and nails made of?
Hair and nails are made of keratin, a type of protein. Both grow from cells under the skin, which grow through different patterns of cell division. The nail matrix is a highly proliferative skin tissue containing layers of keratinocytes.
Nails grow steadily from matrix cells that lie beneath the skin at the base of the nail. These cells divide, pushing old cells forward. As they grow, the new cells slide along the nail bed, the flat area under the nail that appears pink due to its rich blood supply.
Hair also begins to grow from the matrix cells to eventually form the visible part of the hair, which is called the shaft. The hair shaft grows from a root located under the skin encased in a sac called a hair follicle. A hair stands inside a follicle just as a foot stands inside a shoe.
This sac contains a nerve supply (which is the cause of pain when pulling hair), glands that produce oils, which lubricate the hair, and a small muscle that makes your hair stand up when it’s cold.
At the base of the follicle is the hair follicle, which contains the important hair papilla that supplies blood to the follicle.
Matrix cells near the papilla divide to produce new hair cells, which then harden and form the hair shaft. As new hair cells are formed, the hair is pushed up above the skin and hair grows.
But the papilla also plays an important role in regulating hair growth cycles, sending signals to stem cells to move to the base of the follicle and form the hair matrix. The matrix cells then receive signals to divide and begin a new growth phase. Our hair grows in cycles.
Stages of hair growth
Scientists have identified four stages of hair growth that make up the growth cycle:
- The first stage: the growth stage (anagen), which lasts from two to eight years.
- The second stage: catagen stage, when growth slows and lasts for about two weeks.
- The third stage: the resting stage (telogen), when there is no growth at all. This stage usually lasts from two to three months.
- The fourth stage: the shedding (exogen) stage, when hair falls out and is replaced by new hair growing from the same follicle. This process begins again. Each follicle goes through this cycle 10 to 30 times in its lifetime.
If all of our hair follicles grew at the same rate and entered the same stages at the same time, there would be times when a person would be bald. This does not usually happen at any particular time, only one in ten hairs is in the resting phase.
While we lose about 100-150 hairs a day, the average person has 100,000 hairs on their head, so we hardly notice this natural loss.
What things affect the speed of hair growth that do not differ from one person to another?
1- Genes
Genes play the most important role. While hair growth rates vary between individuals, they tend to be similar among family members.
Nails are also influenced by genes, as siblings, especially identical twins, tend to have similar nail growth rates.
2- Age
Age makes a difference in hair and nail growth even in healthy people. Younger people generally have faster growth rates, but with age the growth rate becomes slower due to slower metabolism and cell division.
3- Hormones
Hormonal changes can have an effect. Pregnancy often accelerates hair and nail growth rates, while menopause and high levels of the stress hormone cortisol can slow growth rates.
4- Nutrition
Nutrition also affects the strength of hair and nails and their growth rate. Although hair and nails are mostly composed of keratin, they also contain water, fats and various minerals. As hair and nails continue to grow, these minerals must be replaced. For this reason, a balanced diet that includes sufficient nutrients to support hair and nail growth is essential.
Nutrient deficiencies may contribute to hair loss and brittle nails by disrupting their growth cycle or weakening their structure. For example, iron and zinc deficiency have been linked to hair loss and brittle nails.