What Is a Hair Cuticle? Dr. Joe Explains Why It Matters for Healthy Hair

1. Hair Cuticle

The cuticle is the hair's protective outer shield.

When it's smooth and flat, hair looks shinier, feels softer, and is better protected against moisture loss and environmental damage.

2. Hair Cortex

Beneath the cuticle sits the cortex, which makes up the majority of the hair strand.

The cortex gives hair its strength and determines whether your hair is naturally fine, medium, or thick. 

3. Hair Medulla

The medulla is the innermost section of the hair strand and is typically found only in very thick hair types.

It's made up of soft, thin transparent cells and air spaces.

What Does a Healthy Hair Cuticle Look Like?

A healthy cuticle lies smooth and flat, creating one continuous reflective surface. That's what gives healthy hair its natural shine.

When the cuticle layer is tight and smooth, it acts as an effective barrier, preventing valuable internal moisture from escaping while also stopping excess environmental moisture (humidity) from entering the hair strand.

The result is hair that stays properly hydrated, flexible, glossy and resistant to frizz.

Think of your hair like a mirror: when the cuticle is smooth, light reflects evenly to create brilliant shine. When the surface becomes rough or uneven, light scatters in different directions, making hair appear dull and lacklustre.

What Does a Damaged Hair Cuticle Look Like?

A damaged cuticle appears rough, ragged, and uneven. Instead of lying neatly together, the lifted cuticle layers prevent individual hairs from aligning smoothly.

The result is hair that looks:

• Dry and dehydrated

• Dull rather than shiny

• Puffy or frizzy

• Rough to the touch

• More prone to breakage

High Porosity Hair

If you have high porosity hair, the cuticle is raised and moisture escapes easily. As a result, this hair type is usually dry and dehydrated.

When high porosity hair gets wet, water enters the strand easily—but it also evaporates quickly as the hair dries, leaving hair parched and in need of supplemental moisture.

For healthier-looking, more elastic and glossier hair, high porosity hair typically benefits from products containing moisturising ingredients.

Low Porosity Hair

If you have low porosity hair, the cuticle lies tightly closed, making it more difficult for moisture to penetrate the strand. However, once moisture gets in, it tends to stay there.

Low porosity hair generally takes longer to become wet and longer to air dry, but it often maintains a naturally balanced moisture level.

Because the cuticle is tightly sealed, this hair type is also less prone to frizz, as humidity struggles to enter the strand.

Its biggest challenge is product build-up. Heavy moisturising ingredients with larger molecules often remain on the surface instead of penetrating into the cortex.

1. Dreaming Advanced Repair & Resurfacing Treatment

If you're concerned about weakened or damaged cuticles, Dreaming is the ultimate repair treatment.

Its advanced resurfacing technology smooths, fills and refines the hair's surface while boosting elasticity by 28% and reducing breakage by 83%. 

2. Dream Coat Supernatural Spray

Dream Coat creates an ultra-light, water-resistant matrix around each strand that smooths the cuticle and helps seal out humidity.

The result is silky, glass-like shine with powerful, long-lasting frizz protection that lasts through multiple shampoos.

3. Money Masque

Dry, dehydrated hair often starts with a compromised cuticle.

Money Masque replenishes moisture with powerful marine actives while helping smooth the hair surface, leaving strands softer, silkier and healthier-looking.

4. Dream Cocktail Kale-Infused

Healthy cuticles rely on strong internal hair structure.

Dream Cocktail Kale-Infused helps fortify hair's internal sulphur bonds and is clinically proven to reduce breakage by 50% after just one blow dry, helping hair become stronger and more resilient over time.

5. Pop & Lock High Gloss Finish

As the finishing step in your styling routine, Pop & Lock helps smooth the cuticle while adding glossy shine.

Its unique serum-and-oil formula moisturises and seals the hair surface without leaving behind a greasy finish, making it ideal for polishing your style while helping reduce frizz.

Does cold water close the hair cuticle?

Not permanently. While cooler water may temporarily help the hair feel smoother, it doesn't permanently close the cuticle. Long-lasting smoothness comes from keeping the cuticle healthy and using products designed to refine and protect its surface.

Can you repair a damaged hair cuticle?

Once the cuticle has been physically damaged, it can't permanently regenerate. However, advanced treatments that smooth, resurface, and protect the cuticle can dramatically improve how your hair looks, feels and behaves.

Does bleaching damage the hair cuticle?

Yes. Bleaching and other chemical services lift the cuticle in order to alter the hair's structure. Repeated chemical processing can leave the cuticle rougher, increasing dryness, frizz, and breakage.

Does heat damage the hair cuticle?

Yes. Frequent heat styling can gradually lift and weaken the cuticle, particularly when high temperatures are used without heat protection. Lower temperatures and products with built-in heat protection help minimise damage.

Why does damaged hair look dull?

Smooth cuticles reflect light evenly, creating healthy-looking shine. When the cuticle becomes rough or uneven, light scatters instead of reflecting uniformly, making hair appear dull and lacklustre.