Givaudan study backs cationic hyaluronic acid’s hydrating boost and film-forming ability

06 May 2024 --- A Givaudan-backed study confirms the hydrating benefits of cationic hydrochloric acid at the clinical level due to its “strong” film-forming properties. The molecule showed noticeable benefits at all tested concentrations after seven days of application.

The researchers evaluated the hydrating benefits of the molecule using a combination of clinical biometrics and cognitive measurements. This was done to determine how biological benefits correlated with volunteers’ feelings and perceptions of hydration.

“Through the use of innovative behavioral measurement tools, we were able to show that these outcomes are perceived by naïve consumers in real-life conditions,” state the authors.

The molecule’s hydrating benefits were tested on 22 volunteers in a placebo-controlled study based on the adhesion of cationic hyaluronic acid to the skin’s surface.

Performance in shower gel
The researchers performed a cognitive assessment to assess the perceived benefits of the cationic hyaluronic acid. This was completed in consumers’ homes to ensure the real-life performance of the molecule in a shower gel formulation.

Before the cognitive evaluation and the first application, volunteers answered a questionnaire to clearly define their personal criteria when choosing a shower gel.

The assessment found that cationic hyaluronic acid at 0.03% or 0.1% increases perceived skin softness, comfort and hydration. Volunteers perceived a greater sense of hydrated skin using the formulation containing 0.1% cationic hyaluronic acid than the one with 0.03%.

“The results revealed that the explicit and implicit importance of the criteria used when selecting a shower gel showed consistent patterns,” highlight the researchers.

“Thus, the answers provided by volunteers can be considered authentic, and no attempt was made to hide or modify spontaneous reactions.”

Cationic hyaluronic acid showed noticeable benefits at all tested concentrations after seven days of application in a shower gel. The assessment found that “associated benefits” was the most decisive criterion of choice, followed by “fragrance,” “price,” “natural ingredients” and “skin type.”

Participants perceived a significant increase in skin softness over the seven days of the test, regardless of the formulation. An increase of 13.5% was measured for the 0.03% concentration, and an increase of 8.8% was measured for the 0.1% concentration over the seven days of use. 

The smaller delta between day one and day seven for the 0.1% concentration can be explained by the greater initial certainty that the skin felt softer after just one application than with the 0.03% concentration, according to the researchers.

Skin adhesion and hydration effect
Looking at cationic hyaluronic acid’s physiological effects, the researchers measured its effects on hydration of the skin using a corneometer. This device indicates the hydration level of the superficial layers of the skin (stratum corneum) by measuring the skin’s dielectric properties. 

The results demonstrated a “significant increase” in the corneometer reading of the cationic hyaluronic acid relative to placebo. They further support the molecule’s “significant retention” on the skin with a 14.2% increase and a 115% increase relative to the placebo.

To visualize the skin adhesion properties of cationic hyaluronic acid applied in rinse-off conditions, the researchers performed Hyaluronic Acid Binding Protein (HABP) staining assays.

The results demonstrated that only cationic hyaluronic acid molecules adhered to the skin surface. Relative to untreated explants, a significant 95% increase in HABP signal was observed following application of the molecule, compared to a 12% increase following application of non-cationic hyaluronic acid.

“Overall, these biometric measurements indicated that cationic hyaluronic acid, thanks to its adhesion and film-forming capacity, maintained hydration benefits in rinse-off conditions,” state the researchers.

Delving into emotions and senses
The researchers stress there is growing interest in indirect methods to measure feelings, emotions and sensations related to application of cosmetic products. 

“Today, the effects of active ingredients on well-being can be studied thanks to innovative methodologies including psychophysiological tools to measure volunteers’ peripheral reactions,” they detail.

“For example, the skin conductance response can be used to measure the intensity of volunteers' emotions. As a result, electroencephalography has been used to compare emotions, such as well-being, resulting from the application of two cosmetic products.”

Other tools, such as behavioral observation tools, can be used to measure volunteers’ emotions, they add.

“For example, the action of cosmetic ingredients on the mood of volunteers has been assessed by decoding facial expressions. However, these psychophysiological and behavioral tools all have strong constraints: they involve sensors, specific equipment or dedicated experts.”

“Consequently, they are not compatible with the evaluation of large cohorts,” they note. “In addition, it is impossible for the volunteers to test products in a real-life situation, i.e., in their homes.”

By Benjamin Ferrer