What is hair density? – Hair 101

Have you ever thought about how many individual hairs make up your head? That’s where your hair density comes in. Don’t worry, you don’t have to count your hairs one by one. In this blog, you will discover what your hair density is and how it plays a role in caring for your frizzy hair.

What is hair density?

Hair density is the number of hairs on your head per square centimetre. It refers to how close your hairs are together. There are 3 categories under which your hair can fall:

Image of hair density ranging from low to high density hair

Low hair density

When you have low hair density, it means you have fewer hair follicles per square centimetre on your scalp. This can result in a thinner appearance of the hair and possibly more visible scalp between the hair strands.

Average/medium hair density

When you have an average hair density, you have an average number of hair follicles per square centimetre on your scalp. 

High density

When you have high hair density, it means you have many hair follicles per square centimeter on your scalp.  This results in a full, thick head of hair and less visible scalp between the strands of hair;

Hair density is often confused with hair thickness, but these are two different things.

What is the difference between hair density and hair thickness?

Your hair density is not the same as your hair thickness. When you hear someone say they have thick hair, it often has nothing to do with hair thickness. Your hair thickness refers to the diameter of your individual hairs. It says something about how thick or thin one strand of hair is. Your hair density in contrast, refers to the concentration of hair follicles on your scalp. It indicates how close your hair strands are to each other.

How do you determine your hair density?

There are 4 ways to figure out your hair density. We will briefly go over these:

1. Count your hairs manually

The first way is a simple way of counting your individual hairs per square metre. You don’t need a special machine for this but a lot of patience. On paper, counting your hair one by one is the most accurate way, but it is certainly not practical.

2. Do a visual inspection

A more practical way to determine your hair density is to look at how easy it is to find your scalp. If you can see your scalp without moving your hair, chances are you have low hair density. If it is difficult to see your scalp, you probably have high-density hair. If neither applies to you, then you probably fall into the middle category, where you still have to make some effort to see your scalp.

3. Do the ponytail test

Besides observing your hair, you can also measure the circumference of your ponytail. Put your hair in a ponytail and then measure the circumference of your ponytail. Depending on the circumference you have just measured, you will fall into one of the following categories:

Circumference ponytailHaar density
< 5cmLow density
5cm – 10 cmAverage/medium density
= of > 10 cmHigh density

4. Do a phototrichogram

A phototrichogram is the standard way to measure your hair density. You can’t do this one at home. This is a technique first introduced by Saitoh in 1970. First, a small piece of your hair is shaved. This is followed by a photo taken with a special camera for further analysis. 

5. Do a video trichogram

A video trichogram is similar to the previous example but with video.

Factors that determine your hair density

There are several factors that affect your hair density. There are factors you can control such as your diet, but you also have other factors you can’t do anything about such as ageing, stress and your genes. It is also important to know that your hair density can also change over time and due to external/internal factors.

Genitics

You have no control over your genetic predisposition, but it does affect the density of your hair. Did you know that black hair generally has the highest hair density? Of course, hair colour is only one aspect that affects your hair density. Research shows that there are differences between hair density in different ethnic groups. For instance, people of Asian descent are said to have the highest hair density followed by people of Caucasian descent and finally African descent.

Age

As we age, our hair density begins to decrease. Our hair density is at its peak between the ages of 20-30 and starts to decline from the age of 35.

Health 

There are several health problems that affect the density of your hair. To name a few, consider conditions such as psoriasis, seborrheic eczema and thyroid problems. Hormal changes that occur after pregnancy and menopause can also lead to changes in the density of your hair.

Diet

Furthermore, your diet also affects your hair density. It is important to have a balanced diet, especially since a lack of nutrients including iron and protein can cause hair loss. 

Stress

Stress is not good for you. This also applies to your hair density. Did you know that too much stress can cause temporary hair loss? It is crucial to not only watch your diet, but also get enough sleep and exercise to manage stress. Make sure you take a break and breathe deeply when you feel stressed.

Can you increase your hair density?

Woman with dense afro, holding a pick in her hair.

You cannot increase your hair density naturally because you cannot change the number of hair follicles you have. For this, you need the help of medical procedures. However, you can maximise your hair density by eating healthy, doing scalp massages and reducing stress. Finally, there are ways to make your hair look fuller by using volumising hair products and choosing hairstyles that give your hair a fuller look.

The importance of your hair density 

Your hair density determines the volume and shape of your hair. This helps you understand which hairstyles suit you best and which products you can use to achieve certain hairstyles. An example is using airy products for more volume and the opposite for less volume. Combined with other elements including your hair porosity, elasticity and a less important one like your hair type, you can start finding with your hair routine.

Sources used in this blogpost:

Yetman, D. (2020, October 27). What is hair density and why it matters. Healthline. https://www.healthline.com/health/hair-density#hair-density-test

Van Putten-Rademaker MSc, D. O. (2023, June 29). Haardichtheid en het tellen van haren – Zantman Kliniek. Zantman Kliniek B.V. https://www.zantmankliniek.nl/kennisbank/haardichtheid/

Baeten, L. (2013, June 17). Wat je moet weten over je haar: Dichtheid en elasticiteit. Schrijfmeisje.nl. https://schrijfmeisje.nl/wat-je-moet-weten-over-je-haar-dichtheid-en-elasticiteit

Dhurat R. Phototrichogram. Indian J Dermatol Venereol Leprol 2006;72:242-4.

Marie, G. (2022, July 13). Hair density 101. Curlsmith EU. https://eu.curlsmith.com/blogs/curl-academy/hair-density-meaning-test-care#:~:text=The%20density%20of%20our%20hair,%2C%20health%20conditions%2C%20and%20hormones.

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