How does hyaluronic acid care for your hair?

Hyaluronic acid is above all an ally of dry hair.

Hyaluronic acid is a molecule naturally present in the body, known for its notable ability to attract and retain water. Depending on its molecular weight, it can bind up to 1,000 times its weight in water. In hair care products, hyaluronic acid can be used in hydrolysed form to adhere to the hair fibre surface and penetrate the cuticle in part, or in high molecular weight form to form a protective film on the hair surface. In both cases, hyaluronic acid can provide several benefits to the hair:

• Hyaluronic acid can support porous hair : As a reminder, the hair porosity depends on cuticle integrity, the outer protective layer of hair, and its intercellular cement. The cement is ceramide-based and acts as a semi-permeable barrier that maintains cell cohesion and limits exchange with the environment. When compromised, the cuticle becomes uneven, micropores form and the fibre becomes more permeable. Applying high-molecular-weight hyaluronic acid to this hair type can help compensate for hair porosity by forming a hygroscopic film on the fibre surface that traps water and improves suppleness and elasticity. For improved efficacy, we recommend combining it with a nourishing treatment rich in ceramides, to fill cuticle gaps.

• Hyaluronic acid can prevent split ends : The split ends result from progressive degradation of the cuticle, the hair’s external protective layer. As it wears away, the cortex, the inner part rich in fibrillar keratin, becomes exposed. Breakage may occur, leading to split ends. Regular application of a hyaluronic acid treatment on the lengths can help prevent this. Thanks to its film-forming properties, this ingredient forms a hydrating, protective layer on the hair fibre. It reduces water loss and limits mechanical, thermal, and environmental stresses. By hydrating the hair, hyaluronic acid helps preserve fibre flexibility, protecting against breakage.

• Hyaluronic acid can tame unruly hair : A rebellious mane tends to swell, form frizz and resist styling in humid conditions. Thanks to its hygroscopic action, hyaluronic acid forms a lightweight film around hair, reducing moisture exchange with the environment. By hydrating the fibres, it smooths the cuticle surface, helping to reduce frizz.

• Hyaluronic acid can restore shine to hair : Dull hair indicates damage to the cuticle. When its scales lift or become disorganised, light no longer reflects. By restoring hydration to hair fibres, hyaluronic acid smooths cuticle scales and reinforces their cohesion, enhancing light reflection and increasing shine.

• Hyaluronic acid can reshape curls : Curly, frizzy or coily hair has a more twisted structure than straight hair. This makes its cuticle more irregular and more prone to dehydration. This hair type, water loss alters curl definition and bounce. By boosting hydration in the hair fibre, hyaluronic acid helps define curls and restore suppleness to coily, curly or wavy hair.

To date, the effects of hyaluronic acid on hair have not been validated by clinical studies. The benefits outlined above remain hypothetical, although they are plausible given the well-established properties of hyaluronic acid. in vitro and in vivo on skin.

Note : It is sometimes claimed that hyaluronic acid has the capacity to stimulate hair growth or reduce hair loss. However, while hyaluronic acid injections may have this effect, no study indicates that topically applied hyaluronic acid can do the same.