Hair density refers to the number of hair strands that grow per square centimetre on your scalp. It describes how closely your hair strands are packed together, and affects how full your hair looks.
Hair density varies from person to person but on average, a healthy scalp has about 200 hair strands per square centimeter [1]. Density can be affected by genetics, age, hair loss conditions, and other factors. In this article, we will explore:
Hair density describes how closely hairs grow together on your scalp. Although your hair density influences how thick your hair looks, hair density is different from hair thickness, which describes the width of individual hair strands.
It’s possible to have fine hair with high density, or thick hair with low density. You’re born with all the hair follicles you will ever have, but hair density changes over the course of your life. Here’s what normally happens:
This order can be interrupted at any point by different types of alopecia. Hair loss conditions such as alopecia areata, telogen effluvium, traction alopecia and more can affect hair density. These conditions stop some of your follicles from producing hair, leading to lower density in the affected areas.
One small study investigated the average number of hair per square centimetre. Researchers found that, on average, there were between 124 to 200 hairs per cm² [2].
Based on this information, the table below lists suggested values for low, medium, and high density hair.
Low density
Below 124 hairs per cm²
Medium density
124-200 hairs per cm²
High density
Above 200 hairs per cm²
However, this may vary depending on factors like age and ethnicity. This study also contained only 50 participants, so larger-scale studies are needed to refine these estimates.
Hair density is important for several reasons. If your hair starts to become less dense, you’ll know about it — your locks will look much thinner, and your scalp may even become visible through your hair.
Keeping an eye on your hair density can help you monitor your general health. If your hair is becoming less dense, it may indicate underlying hair loss conditions or medical conditions, particularly if it thins out suddenly.
Your hair density also affects which hairstyles and product choices are best for you. For example, lightweight products are often best for low-density hair, while heavier products may work better if your hair is high-density.
Several factors affect hair density, including genetics, age, and hair loss conditions. Here, we’ll explore each of these in more detail.
Research shows genetics and ethnicity affect hair density. For example, one study suggests that Asian people generally have lower hair densities than people of other ethnicities [3].
A 2018 study investigated the differences in hair density between Hispanic, African, and Caucasian participants [4]. Researchers found:
However, only 166 participants took part and of those, only 23 were Caucasian. Further research is needed to determine how hair density differs across the general UK population.
Researchers have also studied the effects of age on hair density. A 2020 study suggests that hair density decreases with age, with significant differences between people in their 20s compared to those in their 60s [3].
However, this study used Thai participants and only included 79 men and 160 women, so more extensive research is needed to confirm these findings for the general population.
Hair density is not the only factor that reduces overall fullness of hair as you get older. Research suggests that hair diameter (thickness) gradually reduces from age 30 onwards [5].
Several hair loss conditions can reduce your hair density. These include:
There are several ways to work out your own hair density. If you’ve recently taken an interest in your density, it may be because you are losing hair. Here are some of the top ways to identify your hair density and track any changes over time.
Testing your hair density at home means you can start right away. Here are some things you can try:
Although home testing is more convenient, it’s less accurate than professional testing. Here are the ways to find out your exact hair density with diagnostic trichology tests:
Your hair density affects which hair care routine is best for you. Here are some general guidelines to follow:
If you’re experiencing hair loss and your hair is less dense than it used to be, your best option is to seek expert advice. Trichologists are hair loss experts that can professionally assess your density and advise on the best treatments.
Treatment options may include:
A hair transplant is permanent and can give you better hair density for many years to come. If you’re a good candidate for a hair transplant, you’ll have access to some of the best hair transplant surgeons in the UK at the Wimpole Clinic.
Book a consultation at your nearest clinic location to learn how we can help you get your hair back on track.
If you have low density hair, a shorter haircut can create the illusion of density. Low density hair can be prone to looking thin and flat, and it’s easier to add body and volume to a short haircut.
150% density wigs are 150% the thickness of an average head of hair, while 180% wigs are 180% the thickness. Actors and celebrities often choose 180% density wigs because they can give the appearance of a very full head of hair. However, they’re more expensive than 150% wigs.
Using certain hair oils on your scalp can help to increase density if not all your follicles are producing hair. Depending on the cause of your hair loss, oils like rosemary oil for hair loss [8] or pumpkin seed oil for hair [9] may help stimulate hair follicles for growth and increase hair density.
If you’ve always been able to see your scalp through your hair, it’s likely perfectly normal due to your hair density, hair thickness and genetics. If you’ve recently started to see your scalp through your hair and you couldn’t previously, it may be one of the first signs of thinning and balding.
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