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What Makes Hair Curly Or Straight?

What Makes Hair Curly?

For good reason or bad, our hair is often a defining trait from a very young age. Not just what color it is, but how long it is, the style we sport, and whether it is straight or curly. But what causes us to have beautiful pin-straight hair or dazzling ringlets? We are going to discuss the reasons for our hair to be straight or curly, and how you need to care for them both.

Table Of Contents

The Science Of Hair Shape

According to an article published by Northwestern University, two elements of a hair’s structure determine its shape that it grows into. These elements are the shaft and the follicle. The shaft is the part of the hair that we can see – the strands that flow down from our heads. The follicle, on the other hand, is the part of hair which is still within the skin of our scalp. The hair follicle acts as an anchor, holding the hair in place.

It is the shape of the follicle which contributes to determining whether your hair is straight or curly. If the follicle is round, hair will tend to grow straight, while an oval follicle will give wavy hair and a hooked or elliptical-shaped follicle will give you curly hair.

It is thought that certain drugs, such as some cancer treatments, can inhibit receptors on the follicles. That is why some people who have been through chemotherapy made notice their hair grows back curly once treatment has finished. Hormonal changes and humidity can also give you temporary curls.

The angle at which the hair grows out of your skin also affects your hairs’ curliness. Straight hairs tunnel vertically down into your scalp, while curly hairs tunnel in at an angle. This can also affect how oily your hair is, as hair growing at an angle can make it difficult for your natural oils to spread through your hair. That is why curly-haired people may find they don’t have to wash their hair as often as straight-haired counterparts. While this is a great benefit of having natural ringlets, curly haired-people also may encounter scalp irritation and dandruff more.

The shaft of your hair affects how curly it is because of the way protein molecules build up. Proteins such as keratins tend to build up unevenly in curly hair, collecting in the curve of your hair, make it curl even more. This affects your hair less than the shape of the follicle, however.

Looking After Your Straight Or Curly Hair

Looking After Your Hair

Did you know that you may have to care for your hair differently if it is curly compared to being straight? Straight hair is often easier to manage for the reasons we gave above, and you may have to choose your products more carefully if you have irritable, curly hair. If you often encounter a dry, itchy scalp and dandruff that is common for curly hair, you will want to look for a moisturizing shampoo and conditioner that can cleanse your hair and scalp while also halting dandruff.

Curly Hair

Curly hair is notoriously difficult to manage, but it doesn’t have to be as difficult as people make out! The main points to remember are that you want to cut down on frizz and remember it will be more prone to drying out. With that in mind, you can give your curly hair a little extra care, and keep it looking on point!

Remember not to brush your curly hair, especially with a static-inducing bristle brush. Instead, you want a wide-toothed comb to use just before you wash your hair, or simply rake through your hair with your fingers to remove knots and tangles as you condition it. Remember to also not rub it dry with a towel but squeeze it instead with a microfibre towel or even an old t-shirt.

Choose your products carefully. You will probably find that nourishing products such as argan oil, or leave-in masks make your hair feel fabulous, but hairsprays and mousses, which often contain a high proportion of alcohol, can really dry out your roots, leaving your hair feeling crispy or crunchy. Similarly, you will probably find gentle shampoos are best, particularly ones which are alcohol or sulfate-free.

Straight Hair

Resist the urge to brush your hair when it is wet! Hair is weaker when it is wet because it is swollen with water particles. Brushing can cause it to snag, stretch and break, especially if you are using particular types of hair brush such as bristle brushes. Instead, it is better to rake through your hair with your fingers or a wide-toothed comb.

The impact of static is also more noticeable if you have straight hair, for example, flyaway hairs! To reduce this, we recommend using ionic heat tools when you are styling it, which cut down the static electricity. Split ends are also more noticeable, so you may find you have to have a trim more often that your curly hair friends!

You will also want to avoid using too much product in straight hair. The build-up is more noticeable in straight hair and this can weight it down and make it look greasy quicker.

Styling Your Hair

Styling Your Hair

Whether you have straight, wavy or curly hair, chances are at some point, if not regularly, you will want to style your hair differently. We have recently tested the most popular heat styling tools and discussed them so that you can easily find which model is right for you. See what the OGLF Team decided what the best curling iron and see our tests of the top curling wands.

Whether you are looking for a new blow dryer, a different curling iron, a better flat iron, or fancy giving a new tool a go, such as a hairbrush straightener, we have reviews to help you! If you already have a wardrobe full of these tools, have a look at the rest of our blog where we can help you get the most out of them!


  1. Miss Lois

    My hair has been straight my whole life. However in the past 5 or 6 years I have 2 places in the back of my head which have become curly! The areas are getting bigger. It almost looks like I have horns! I have never had chemo. I went through menopause 25 years ago. What’s up?

  2. MadyKay

    But my hair is both straight and curly, with a little bit of wave here and there. My dad is a red head (and do am i) and you can imagine his curls, but my mom has pencil straight hair. I’m the past two years my hair has become a dark shade of red and the curls more defined, and the straight parts straighter. I get weird looks all the time because of my hair and it makes me really insecure.

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