How fast does hair grow? Growing your hair out is easier when you know how much growth you should see in a month or a year. We’ll show you the average hair growth rate and science-backed tips to grow it faster.
Wait, Hair Growth Rate Matters?
Most people don’t give hair growth a second thought. It’s like breathing – you don’t have to think about it. It just happens. But if you’re trying to grow your hair out or notice that your hair looks thinner than it used to, hair growth suddenly becomes very important.
How fast does hair grow normally? How long will it take to reach your desired length? And is your hair growing at the right rate?
Researchers and scientists have been fascinated by hair for centuries. And each year, we learn more and more about the “why” behind hair growth. We now know the average growth rate for hair, the factors that affect hair growth the most, and the things we can do to increase our hair growth rate.
Keep reading to see how fast hair grows on average, the factors that influence growth, and what you can do to ensure you’re getting optimal hair growth.
How Fast Does Hair Grow?
Hair is the second-fastest-growing thing on the body (bone marrow is the first). It might seem like hair takes forever to grow because the growth amounts are so small. Overall, the average hair growth rate is about 0.4 to 0.5 inches per month, or 6 inches a year.
Daily growth is very hard to notice because it’s so slight, but hair grows about 0.44 millimeters each day. Different hair types can grow slower or faster than this. Several factors affect how fast hair grows (we’ll talk about these in the next section).
If you have an average growth rate and shave your hair off, you’ll have hair that is roughly 6 inches long in a year – around the ear or chin level, depending on your hair type.
Factors that Affect Hair Growth
The speed of hair growth depends on many factors that range from genetic to environmental. Wondering what factors could be affecting your hair growth? Here’s what’s working behind the scenes to determine how fast or slow your hair will grow.
Hair growth rates are different for Asian, African, and Caucasian hair types.
- Asian hair grows the fastest at about 411 µm (micrometers, equal to .001 millimeters) per day. That growth rate results in around 0.48 inches of hair growth per month in Asian hair.
- African hair has a slower growth rate at about 280 µm per day, or about 0.32 inches per month.
- Caucasian hair falls somewhere in the middle, with an average daily growth rate of 367 µm. That results in about 0.42 inches of hair growth in a month.
One study looked at the hair growth rates for men and women from different ethnic groups. South Africans, Western Africans, and African Americans had the slowest hair growth rates.
Peruvians, Russians, and Caucasian Americans were in the middle. Chinese, Korean, and Japanese had the fastest hair growth rates. After a year of hair growth, Asian hair will naturally be about 5 centimeters longer than African hair.
Gender also affects the rate of hair growth. Studies have found that male hair grows a little faster than female hair. It usually moves through the hair cycle faster, so it doesn’t get as long as female hair before shedding and starting over.
But the rate of growth is faster. So if you’re a man, you can expect that your hair may grow a little faster than 0.5 inches per month. If you’re a woman, your hair should grow around 0.4 to 0.5 inches per month while accruing more length than male hair over time.
Age is another major factor in your hair growth rate. Hair growth is partially regulated by hormones, of which our bodies adjust production over time. Between ages 15 to 30, hair growth is at its peak.
After that point, some follicles will stop growing new hairs entirely. This means some hairs that are shed through the natural hair cycle will not grow back. Over time, this can result in noticeable thinning in areas or all over the head.
Genetic and environmental factors influence age-related hair loss, so some people may not experience a noticeable reduction in hair growth as they age.
Diet and Nutrition
Your diet and nutrition influence your hair growth greatly. Since hair is composed of protein, we know that we need to get enough protein and amino acids (protein’s building blocks) to grow our hair.
But we also need proper amounts of iron, zinc, niacin, fatty acids, selenium, vitamins D, A, and E, folic acid, biotin, and antioxidants for hair growth. If you’re not getting the recommended amounts of nutrients, vitamins, and minerals in your diet, your hair growth rate suffers.
Suddenly reducing calories or protein amounts can result in sudden hair loss, as can significant weight loss.
Your genetics also influence your hair growth rate. Every person’s hair enters a growth (anagen) phase, where follicles actively produce new hair cells that result in longer strands.
Your genetics might cause you to have a short anagen phase – say, 2 or 3 years long – while another’s could be as long as 6 or 7 years.
The longer any given hair is in the growth phase, the more opportunity your hair has to grow before being shed and replaced by new hair. Genetic disorders can also affect hair growth, with some causing premature shedding and shorter growth phases.
Stress affects your rate of hair growth tremendously. If you’re losing a lot of hair – more than the typical 50 to 100 hairs per day – you could be experiencing a phenomenon called telogen effluvium.
In telogen effluvium, extreme stress causes your scalp to signal actively growing (anagen phase) hair strands to enter the catagen and telogen phases. This can result in as much as a 70% loss of hair.
It makes sense that keeping stress levels low can encourage hair growth by keeping your follicles in the growth phase rather than shocking them into the rest/end phase, resulting in shedding.
Hair breakage doesn’t technically affect growth, but it can make it seem like your hair isn’t growing like it should. If your hair is weak and damaged (or handled roughly), it can break off before it’s time for the hair to shed.
Eliminating the cause of breakage is one way you can make your hair appear to grow faster.
The Hair Growth Cycle
We’ve seen how fast hair should grow and what factors influence the growth rate. Let’s talk about the hair growth cycle. First, we’ll take a quick peek into how your hair grows.
Your scalp has about 100,000 follicles, which are the small pockets where hair grows from. Roots in the follicles produce the hair. Hair is made of protein (keratin) cells that grow in a strand formation.
The scalp’s blood vessels feed each follicle and root. As the follicles and roots are fed, hair begins to grow by poking up through the skin of the scalp. Small oil glands near each follicle help keep the hair moisturized and shiny.
Over time, your body naturally signals each follicle to stop the blood supply to its growing hair. Then, the hair will naturally shed and make way for a new hair to grow in its place.
Hair growth takes place in 3 distinct phases: Anagen, catagen, and telogen. Here’s what each phase entails.
Anagen Phase: Growth
The anagen phase is the growth phase. The Greek prefix ana- means up. This is the term for the phase when the hair is actively growing. Every strand of hair on your head goes through an anagen phase, which lasts anywhere from 3 to 5 years.
In Asian hair, the anagen phase can be as long as seven years. If you don’t cut hair during the anagen phase, the hair will end up being anywhere from 18 to 30 inches long.
Catagen Phase: Transition
After the anagen phase, the hair enters the catagen phase. The catagen phase is considered a transitional phase. The Greek prefix cata- means down. Hair doesn’t stay in this phase for long – about 2 to 3 weeks.
During the catagen phase, the hair stops actively growing and changes into a club hair. A club hair refers to a hair strand whose blood supply has been cut off.
Telogen Phase: Rest
The third phase of the hair cycle is the telogen phase. The Greek prefix telos- means end, and that’s precisely what’s happening during this phase: The end of the growth and transition period. This resting period lasts around three months.
During the telogen phase, the hair strands are still in their follicles. They just aren’t growing anymore. This phase lasts for about nine months. Any hair you shed is hair that is in the telogen phase.
How to Encourage Faster Hair Growth
Increasing the rate at which your hair grows is possible when you take all the factors that affect growth into account. There are some factors you can’t change – like ethnicity, genetics, age, and gender.
But there are a couple of factors you can change. The two main ways to increase hair growth are proper diet/nutrition and addressing the root cause of breakage.
Improve Your Nutrition
Hair has a few nutrient requirements that need to be met for it to grow at the proper rate. When those requirements aren’t met, the hair doesn’t have the supplies it needs to grow.
Scientists have found that humans need the following to achieve maximum hair growth and avoid hair loss:
- Iron: Iron-deficiency anemia is associated with telogen effluvium
- Zinc: Patients with low zinc levels are more likely to have a range of hair loss problems and reduced hair growth
- Niacin: Severe niacin deficiency is linked to hair loss and reduced hair growth
- Selenium: People deficient in selenium tend to have sparse hair with slower growth
- Vitamin D, A, E: Low levels of these vitamins are associated with slower hair growth
- Folic acid: Low levels are associated with slower hair growth; supplementation shows promise of increasing growth
- Biotin: A biotin deficiency can cause hair loss and reduced hair growth
- Amino acids and proteins: Consuming too little protein results in hair loss and reduced growth
If nutritional deficits are the culprit behind your slow hair growth or hair loss, you can ensure your diet is rich in iron, zinc, niacin, selenium, vitamins, biotin, and protein to increase your hair growth rate.
Address the Root Cause of Breakage
If your hair seems to be growing at the normal rate but breaking off, you need to address the root cause of the breakage to let your new hair growth accumulate. You’re essentially “trimming” the ends of your hair all the time if your hair is damaged to the point of breakage.
Here are the main activities that can cause hair breakage that makes your growth seem reduced:
- Unprotected use of heat styling tools (curling irons, flat irons, blow dryers)
- Chemical processing (colors, bleach, perms, relaxers)
- Improper moisturization of hair
- Rough treatment of hair (towel drying, tight hairstyles, wet brushing, etc.)
What are you doing that weakens your hair? If you use a hot styling tool every day, try to limit your use to a few times per week and make sure you’re using a good heat protectant on your hair first.
If chemical processes are weakening your hair to the point of breakage, it’s time to take a break from the colors, bleaching, or perms.
Dry, brittle hair is very prone to breakage, so if your strands seem thirsty, invest in a good conditioner or hair mask to restore moisture and decrease breakage.
For manual breakage caused by rough handling or styling of the hair, take steps to be more gentle with your hair. Looser styles, avoiding towel-drying, and sleeping on a silk or satin pillowcase can help.
So, How Fast Does Hair Grow?
Overall, the rate of our hair growth is something our bodies determine for the most part. But we can stack the odds in our favor by paying attention to our diet and nutrition and monitoring our hair health.
Make sure you’re taking a multivitamin and getting your recommended daily amounts of nutrients and minerals.
Be gentle on your hair, keep it moisturized, and go easy on hot styling and chemical processing. If you address those two root causes of reduced hair growth, you will see faster growth that looks and feels healthier.