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Dry Hair: You’ve Been Lied To. Here’s Your Ultimate Science-Based Guide To Dry Hair

Have you ever experienced dry, brittle hair that seems unmanageable and lacks lustre? In this blog, we'll dive deep into the science behind dry hair. Specifically, we’ll take a look at what causes dry hair, along with the treatments for dry hair.

Distressed woman with dry hair

What Causes Dry Hair According To Science

Most blogs will tell you that dry hair is a condition in which the hair lacks sufficient moisture and natural oils, leading to a rough texture, brittleness, and increased vulnerability to damage. This however, is not true.

In an excellent YouTube video on dry hair, Sarah Ingle discusses the myths and misconceptions surrounding dry hair. I’m putting the video here for those who want to watch it.

Sarah’s video is based on one of the most respected sources about hair, a dense book by the name of “Chemical and Physical Behavior of Human Hair” by Dr. Clarence R. Robbins. In the video Sarah explains that many commonly accepted ideas about hair are wrong, and could even be encouraging people to engage in practices that damage their hair. Finding science-based information on hair is usually difficult and expensive and the most respected sources are not widely known. The cosmetics industry also often controls hair education, and sometimes pushes ideas that aren’t scientifically accurate if those ideas will make their products sell.

This is where the misconception of “dry hair” comes in. According to Sarah, the terms "moisturised" and "dry" have been used incorrectly to describe hair for years. When people say dry hair, they are often referring to hair with less water, and the opposite when they talk about moisturised hair. Counterintuitively in surveys however, people rate hair with higher water content as dry, and vice versa. In other words, hair with less water looks and feels nicer than hair that is holding on to more water.

In reality, when people use the term "moisturised", they really mean conditioned - products that are usually sold as moisturising products don't add water to hair; they simply condition it, where conditioners act by neutralising negative charges on the hair and are used to decrease friction, detangle hair, minimise frizz and improve manageability.

In other words, dry hair that feels rough and seems unmanageable and lacklustre is simply hair damaged hair, and not hair that lacks water, or moisture.

Dry Hair (Damaged Hair) vs. Healthy Hair: What’s The Difference

Hair consists of three main layers. The outermost layer of the hair shaft is called the cuticle and is made up of overlapping scales that protect the inner layers. The cortex is the middle layer and comprises elongated cells containing keratin fibres and melanin granules. These give hair its strength, elasticity, and colour. The innermost layer is known as the medulla and is a soft, spongy mass of tissue that is usually present in coarse hair but absent in fine hair.

Simplified cross section of the hair showing the cuticle, cortex and medulla

In healthy hair, the scales of the cuticle lie flat and form a smooth, continuous surface that reflects light resulting in a natural shine. In dry hair however, the scales of the cuticle scales are damaged, lifted, or cracked. This leaves the cortex of the hair more exposed to the environment; it also means that light is scattered and not reflected in the same direction off the surface of the hair. As a result, damaged hair appears lacklustre and lacks shine. According to a 2011 study published in the Annals of Dermatology however, there is no statistically significant difference in the moisture content between dry hair, or damaged hair and healthy hair.

Damaged and healthy hair under a scanning electron microscope

What Causes Dry Hair (Or Damaged Hair, Now That We Know Better)?

Several factors can contribute to dry hair. Some of the most common ones include:

Chemical damage, physical damage and heat damage can cause dry hair

Frequent use of chemical treatments including bleaching and hair dyeing, damage the outer layer of hair, called the cuticle. This changes the shape and texture of hair, making it rough, less shiny, and harder to comb or brush. Physical damage from friction caused by hair accessories, washing, towel drying, and daily grooming, and heat damage from heat styling tools including hair dryers, curling irons, and straighteners can also lead to significant surface damage in the form of cracks, and holes in the hair cuticle, resulting in dry hair.

Exposure to environmental factors can cause dry hair

Ultraviolet radiation from the sun can damage hair fibres, leading to dry hair, rough texture, and colour changes. Additionally, exposure to harsh weather conditions, pollution, and chlorine in swimming pools can also cause dry hair.

Ill-formulated hair care can cause dry hair

Shampooing with alkaline products causes hair to swell and damages the hair’s ultrastructure and cuticle, potentially contributing to dry hair. Shampoos are frequently formulated to be alkaline. Other hair products with an alkaline formula however, have the same effect.

How to Treat Dry Hair (Dry Hair Treatment)

Now that we've explored the differences between dry and healthy hair, let’s discuss how to care for dry hair effectively. Here are some tips to help you maintain and restore your hair's health and moisture:

Choose the right shampoo and conditioner for dry hair

Select pH balanced, gentle products that respect the biology of your skin and hair and don’t cause your hair to swell up, resulting in cuticle damage, every time you use them. Always condition your hair after you wash it. Conditioner forms a thin film on top of the hair that improves shine, but also helps strengthen and protect hair and makes it easier to detangle, indirectly helping to reduce hair breakage. Our Clarify and Rebalance Shampoo and Strength and Shine Conditioner have been formulated bearing the science behind your hair in mind. Our conditioner is also weightless and can be used as a leave-in conditioner for hair that needs extra protection. Leaving in conditioner helps to protect your hair throughout the day, and provides an extra layer of defence against environmental factors that can cause dry hair. You’ll notice the difference in the quality of your hair from the very first time that you begin using these products.

Limit the use of heat styling tools, but dry your hair properly

The cell membrane complex (CMC) is a lipid-rich region that acts as a binding agent between the cuticle and cortex. It provides flexibility and strength to the hair shaft. In healthy hair, the CMC is intact and undamaged. Extended exposure to a wet environment however, damages the CMC. So what’s the science-backed method to dry your hair to minimise damage? Use a hair dryer but hold it 15 cm away from your hair and leverage continuous motion so no single segment of your hair is exposed to heat for too long. That said, still avoid excessive use of heat styling tools like flat irons, curling irons, and hair dryers and consider using lower heat settings where possible, to minimise heat damage.

Protect your hair from the sun

As it is for the skin, UV exposure is also one of the most common causes of structural damage to the hair. The effects of sun exposure on hair include degradation and loss of hair proteins and changes in hair colour, where UVB radiation is responsible for protein loss , while UVA radiation is responsible for colour changes. Bleaching of the hair due to excessive sun exposure also makes it more susceptible to UV damage. This is because melanin absorbs and filters UV radiation and plays an important role in protecting hair proteins from the sun. Loss of melanin from the hair thus, results in hair that is more susceptible to UV damage. To protect your hair from the sun, avoid prolonged sun exposure and wear a hat or use a UV-protectant spray to shield your hair from the sun's harmful rays.

Be gentle when handling wet hair

Wet hair is more susceptible to breakage. Gently pat your hair dry with a soft towel to remove excess water, and use a wide-tooth comb to detangle it.

Maintain a healthy diet and stay hydrated

Hair health starts on the inside. While cosmetic products definitely have their place, they’re not a substitute for a nutritious, well balanced diet.

Additional Expert Tips For Dry Hair Treatment

In addition to the general tips for caring for dry hair, here are some expert recommendations to help you better manage and prevent dry hair:

  • Trim your hair regularly: Regular trims can help remove split ends and minimise further damage to your hair.

  • Sleep on a silk or satin pillowcase: Silk pillowcases result in less friction while you sleep resulting in less overall damage to your hair.

  • Don't brush your hair too often: Brushing the hair creates friction and can damage the hair cuticle. It can also cause hair breakage. Instead, use a wide-tooth comb or a brush with soft bristles to gently detangle your hair.

  • Apply a hair serum or oil to your ends: Applying a hair serum or oil, such as our Frizz Control and Shine Hair Serum, provides an extra layer of protection to your hair. It also makes it shinier and more manageable. Apply the serum when your hair is still damp starting from the ends. Start with a little and add more until you’re satisfied with the final look and feel of your hair.

  • Use a protein mask like our Damage Repair Protein Hair Mask once a week; ramp usage up or down depending on how damaged your hair is. Polypeptides and proteins attach to the surface of hair, while small molecules can even penetrate into deeper layers of the hair, particularly if it's damaged. Proteins help protect hair from chemical and environmental damage. They help seal hair cuticles, especially when used with heat styling tools, thus improving hair colour and shine. Damaged hair, especially bleached hair, retains more protein. This helps reduce the frizz usually associated with such hair. Don't, however, overuse hair products with protein. Proteins build up on the surface of the hair and too much can cause the hair to feel rough and make it more prone to breakage if overused.


Dry hair is a common concern for many people. An understanding of the underlying causes and structural differences between dry hair and healthy hair can help us make informed decisions about the best hair care routine to manage dry hair.

Incorporating the tips we've discussed – from choosing the right products and limiting heat styling to implementing expert recommendations – can help you effectively manage and improve the condition of dry hair. Remember that consistency is key, and with proper care and attention, you can restore your hair's health and maintain its natural shine and vitality.

As always, you can also drop us a message on WhatsApp for a free skin and hair care consultation: 0302-2228349.


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