Journal of Physical Chemistry & Biophysics
Open Access

Abstract

Hyaluronic Acid: Elucidating its Penetration and Effect through the Hair Fibre Using Confocal Raman Spectroscopy and Biometric Techniques for a Set of Cosmetic Benefits

Boira Cloe*, Essendoubi Mohammed, Meunier Marie, Lambert Carole, Auriol Daniel, Manfait Michel, Piot Olivier, Scandolera Amandine and Reynaud Romain

Background: Hyaluronic Acid (HA) is well known in the cosmetic industry for its hydrating properties linked to its interaction with keratin in the stratum corneum. Hair is also mainly composed of keratin, but no evidence of penetration and interaction of HA in hair has been established yet due to a lack of appropriate methods.

Methods: Confocal Raman Spectroscopy was used to track HA penetration in hair fibres. Human hair was either UV-irradiated or left untreated before being washed with various shampoo formulations. Low-Molecular Weight hyaluronic acid (LMW at 1% w/v), High-Molecular Weight HA (HMW at 1% w/v), and an optimized blend of low-and high-molecular weight HA (HA-Blend at 1% w/v) were used. The benefits of HA for cosmetic application has been then evaluated at the ex vivo level regarding smoothing, reparative and hydrating properties.

Results: Raman analysis of non-irradiated samples revealed that HA-blend penetrated the hair cortex 5.9 times more than the placebo, with irradiated samples a 1.8-fold increase in penetration was observed. Whatever the irradiation status, penetration of this optimal HA-blend was significantly higher than that of the other two actives. Compared to the placebo, the HA-blend significantly decreased the spontaneous frizzing by -11%, repaired the hair by increasing the elastic modulus and the break force and increased the water content into the hair shafts.

Conclusion: Based on the results obtained, Confocal Raman Spectroscopy can be considered as a powerful, non-invasive technique to investigate the penetration of active ingredients into the hair. The optimized formulation containing both LMW and HMW HA in different proportions penetrates deep into the hair cortex and provides a durable smoothing, reparative and moisturizing effects.

Published Date: 2024-02-23; Received Date: 2024-01-24