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The Scientific Truth Behind Curly Hair

The science behind hair that twists and turns.

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Have you ever wondered why some hair is straight, and some is curly? Of course, the scientists at Kérastase are eternally intrigued by why hair behaves in certain ways. We harnessed the power of L’Oreal Research to analyze all types of curls in 23 countries around the world. Here’s what we found.


All hair textures are biologically the same. Where they differ is in the actual shape of the fiber and the follicle. Curly hair is born deep in the scalp from a curved bulb, and takes its winding shape due to irregularly distributed keratin, the building blocks of hair.

The 3 Ways Curly Hair Is Special

Though all hair is biologically the same, curly hair has distinctive characteristics that demand a different approach to care.

1. Curls are naturally drier and more porous.

In general, curly hair is more porous than straight hair, which alters its ability to absorb and retain moisture and caring agents. For this reason, curly hair needs very rich, nourishing care.

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2. Curls are thinner and more fragile.

Because of its texture, curly hair is more delicate and easily sensitizes. It tends to take more wear and tear from daily styling, braiding, and even sleeping. Exposure to the mechanical stress of brushing and detangling can lead to breakage. A study conducted on curly hair shows that it requires 5-50x the combing force of straight hair. Extra strengthening products are essential.

3. Curls have a spiral shape that makes it difficult for oils and caring agents to migrate from root to tip.

On straighter hair, care products can easily slide along the length of the fiber, hydrating further down the shaft. Curly hair is drier because the caring agents don’t reach as easily due to the shape of the curl. The key to curly hair care is to add gliding agents to help diffuse.

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Curls Deserve the Best Care

We celebrate all types and textures of hair. Through scientific curiosity and cultural inquiry, Kérastase is working to address the special demands of curls and coils. We continue to apply our philosophy of innovation to make the impossible possible, providing three key benefits to curly hair:

1. Hydration with fine Manuka Honey to heal porosity and nourish the fiber.

2. Strength with biomimetic ceramide that acts like the hair’s own “cement,” deep in the cortex.

3. Glide with diffusing Glycerin that carry ingredients from root to tip for perfect definition.

At last, luxury meets performance in a hair care line that empowers women
to wear their beautiful curls with confidence and pride.


Rendez-vous at the salon

Far more than the place to get your root touch-up or an occasional trim, book an appointment at your nearest Kérastase salon for a complimentary personalized hair diagnosis.


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