How long and fast hair grows depends on factors such as genetics, age, gender and hormones. Nutrient deficiency, hormonal fluctuations and other factors may reduce the rate of hair growth.
With that said, exactly how long does hair grow in a month?
A study done by the American Academy of Dermatology showed that on average hair grows about ½ an inch per month. That is about 1.27cm of growth per month
In a year, that is about 6 inches of growth (equivalent to 15.24 cm per year)
To understand more about the rate of hair growth, we will delve in the following;
- Factors that affect hair growth rate
- Hair growth phases
- How to promote healthy hair growth
Hair Growth Rate
We’ve seen above that the average hair growth rate per month is ½ an inch. This however varies depending on various factors as described below:
The gene make up of an individual contributes to how long, thick and fast their hair grows. For example, there are variations in the rate of hair growth among different race.
The following table shows the differences among the three races in hair growth rate as well as other hair features.
|Asian Hair||Caucasian Hair||African hair|
|0.55 inches (1.4cm) growth rate per month||0.47 Inches (1.2cm) growth rate per month||0.35 inches (0.9cm) growth rate per month|
|Straight||Straight, wavy, or curly||Tight curls and kinks|
|Dark brown or black||Blonde or dark brown||Black|
|Grows perpendicularly to the scalp||Grows diagonally to the scalp||Curls upon itself|
|Follicles are somewhat round, even shape||Follicles are oval in shape||Follicles are flat in shape|
Male hair grows faster compared to that of a female. Males have a higher testosterone level compared to females. Testosterone makes hair thicker. Thicker hair is associated with longer hair.
Hair grows faster when young and tends to slow down as we grow older. This is because the rate of new hair follicle development slows down with age.
A healthy and balanced diet provides a conducive environment for strong and shinny hair. Food rich in protein also help in keeping your hair strong and healthy.
Read this article to learn more on hair growth vitamins.
A healthy scalp promotes hair growth.
When the scalp is unhealthy, and has dandruff or other infections, your hair follicles get inflamed and your scalp gets itchy. As a result, new hair cannot be formed.
Using hair products that add nutrients to your hair results to healthier, stronger, and thicker hair.
On the other hand, using harsh products on your hair drains your hair of its natural oils. They also weaken it and leads to breakage.
Studies show that stress affects the natural process of hair growth. It leads to a temporary condition called Telogen effluvium that is characterized by hair loss. 
Exercising ensures continuous blood flow to your scalp. This benefits your hair follicles. This can also serve as a good stress reliever; therefore, you would be killing two birds with one stone.
Spoiler Alert 🙂 Did you know hair porosity plays a key role in hair growth? Take this simple hair porosity test to determine if your hair high, low or normal porosity.
Hair Growth Phases
The process of hair growing from its roots to its shedding goes through four phases namely:
- Anagen (The active growth phase)
- Catagen (The transition stage)
- Telogen (The resting phase)
- Exogen (The shedding phase)
In this phase, the cells in the root of your hair are actively dividing to form new hair. This phase lasts between 2 years and 7 years, and this varies from person to person.
It is also the dominant phase on your hair since most of your hair is going through the growth phase.
The anagen phase varies for the different hairs on your body. Your scalp hair’s anagen phase is different from that of your pubic hair’s and eyebrow hair’s.
This is a transitional stage and begins immediately the anagen phase comes to an end. In this phase, individual hairs are cut off from direct blood supply and cells that produce new hair.
As a result, your follicles shrink forming what is commonly known as club hair.
At least 3% of your hair will be going through this phase. The catagen phase lasts for 2 to 3 weeks approximately.
This is your hair’s resting phase. In this phase, your hair is dead and full of keratin. Pulling a strand of hair at this phase leaves a solid, hard, dry, white material at the root.
The telogen phase lasts about 90 days to 120 days. 6% to 8% of your hair is in this phase.
The exogen phase is where your hair sheds off. This gives room for the whole growth process to begin. The shedding off phase is assisted by how often we wash and comb our hair.
The exogen phase approximately lasts for 2 to 5 months.
The growth cycle is very specific for every hair follicle and that is why your hair does not fall out at once.
Allowing your hair to go through the growth process without any disruption enables it to grow out longer as it goes through the anagen phase continuously.
How to Promote Healthy Hair Growth
Have a healthy diet
Your body needs energy for hair growth. Vitamins such as vitamin C, D and E, zinc, iron and fatty acids (omega-6 and omega- 3) protect against hair loss.
Incorporating this in your diet keeps your body ready for the hair making process.
Use essential oils
We all love essential oils because they leave us smelling nice but there is more to them than just a great scent.
Essential oils promote hair growth. Some that you can incorporate to your routine include: pumpkin seed oil, peppermint oil and rosemary oil. These have been scientifically proven to promote hair growth.
Incorporate scalp massages
Science shows that massaging your scalp relieves stress but also boost your hair health.
Massaging the scalp, dilates your blood vessels leading to thicker and stronger hair. You can do this by yourself or every time you visit your hair salon.
Minimise using heat
Excessive heat on hair leads to weak and damaged hair so its best to avoid it. You can also apply a heat protecting product on your hair. This will help your hair retain its moisture and reduce hair breakage.
In a nutshell, how long hair grows depends on factors such as genetics, age, hormone, diet but on average hair grows about 1/2 an inch per month. To promote healthy hair growth, have a healthy diet, use essential oils, massage your scalp and be patient.