Moisture retention of glycerin solutions with various concentrations: a comparative study

Abstract

Various methods of evaluating a humectant’s moisture retention have unique mechanisms. Hence, for designing advanced or efficient ingredients of cosmetic products, a clear understanding of differences among methods is required. The aim of this study was to analyze the moisture-retention capacity of glycerin, a common ingredient in cosmetic products. Specifically, this study applied gravimetric analysis, transepidermal water loss (TEWL) analysis, and differential scanning calorimetry (DSC) to examine the evaporation of glycerin solutions of different concentrations. The results revealed that the moisture-retention capacity of glycerin increased with the glycerin concentration from 0 to 60 wt%, and glycerin at concentration of 60–70 wt% did not exhibit weight change during the evaporation process. When the glycerin concentration exceeded 70 wt%, moisture sorption occurred in the glycerin solution. Furthermore, the results revealed a deviation between the evaporation rates measured using gravimetric analysis and those measured using TEWL analysis. However, normalizing the results of these analyses yielded the relative evaporation rates to water, which were consistent between these two analyses. DSC thermograms further confirmed the consistent results and identified two hydrated water microstructures (nonfreezable water and free water) in the glycerin solutions, which explained why the measured evaporation rate decreased with the glycerin concentration. These findings can be applied to prove the moisture-retention capacity of a humectant in cosmetic products by different measuring methods.

Polymer Microtip-Based Fabry–Perot Interferometer for Water Content Determination in the Gas and Liquid Phase

“…In our case, the diameter of the PETA tip is about 5.0 μm, so the change in the effective refractive index of the guiding mode due to the evanescent field is insignificant. We propose that the strong water absorption capacity of glycerol is the main reason behind the shift of the FPI signal . The tip is always immersed in pure water before being immersed in aqueous glycerol solutions, so that the PETA hydroxyl groups are initially saturated by water molecules.…”

Preparation and efficacy verification of three‐dimensional printed partitioned multi‐effect precision‐care gel facial mask

“…Glycerol is a polyol humectant, and the hydroxyl groups in its molecules form hydrogen bonds with water molecules, thereby playing a role in water retention. Sodium hyaluronate is composed of D-glucuronic acid and N-acetylglucosamine [20,21,36], macromolecular helical structures with hydroxyl groups located inside the helical structure. Due to its low external hydroxyl density, the short-term moisturizing effect was not significant.…”

“…Based on the screened gel matrix with the highest score, the gel was prepared by adding four humectants with different concentrations: Glycerol (3, 5, 7, and 10 wt%) [20], propylene glycol (3, 5, 7, and 10 wt%), butanediol (3, 5, 7, and 10 wt%) [21], and sodium hyaluronate (0.2, 0.4, 0.6, and 0.8 wt%) [22]. The moisturizing properties of gel formulations with different humectants were evaluated using an in vitro method [23].…”

Citrus Waste Upcycling toward Pectin Moisturizer Films Plasticized with Glycerol and Polyethylene Glycol

“…Variations in moisturization within the pectin plasticized films are linked to the distinct properties of the plasticizers. GLY has humectant properties, attracting and retaining moisture to enhance skin hydration, 42 while PEG contributes to moisture retention in a unique way due to its larger molecular size and skin interaction. The combination of GLY and PEG may offer a synergistic effect on moisturization, explaining the observed increase in moisture retention.…”