554 JOURNAL OF COSMETIC SCIENCE
effect of makeup, making its efficient removal challenging with common surfactant-based
cleansers like soaps or oil-based cleansers.7
An effective alternative for skin cleansing consists of micellar waters. Micellar waters are
aqueous solutions containing surfactant molecules that form micelles, which are capable
of absorbing dirt and oil from the skin. These micelles consist of hydrophobic tails and
hydrophilic heads. When applied to the skin, the hydrophobic tails bind to oils and
impurities while the hydrophilic heads remain in the water, which allow the micelles to
encapsulate and lift away dirt and makeup effectively.8
Micellar waters are particularly gentle and suitable for sensitive skin because they clean
without the need for harsh scrubbing or rinsing. This makes them an ideal choice for those
with delicate skin conditions. Moreover, the nonionic surfactants used in some micellar
waters, such as glycerol esters, are designed to mimic the skin’s natural lipids, which ensure
a mild cleansing action that maintains the skin’s barrier without causing irritation.9
In addition to concerns about preserving the skin barrier, recent years have seen increased
attention on the impact of cosmetic products, particularly skin cleansers, on the skin
microbiota.10–12 Conventional soaps, for instance, can potentially disrupt the natural
microflora of the skin, thus resulting in imbalances within the microbiome.13 In addition
to the importance of developing makeup removal solutions that are microbiome-safe,
the adoption of strategies that adequately modulate the microbiome (such as the use of
prebiotics) has shown promise in restoring microbial balance and improving skin health.14
Prebiotic ingredients can exert positive effects on the host’s health by selectively stimulating
the growth of specific beneficial microbes.15
In this work, the effectiveness of a prebiotic aqueous micellar solution was tested specifically
for its ability to balance the skin’s microbiome while cleansing and removing makeup
without damaging the skin barrier.
MATERIALS AND METHODS
PREBIOTIC AQUEOUS MICELLAR SOLUTION
A commercially available bulk solution (Bio-Balance Water, Chemyunion Ltda., Sorocaba,
SP, Brazil) was tested for its efficacy in removing makeup and its impact on the facial skin
microbiome. This bulk solution contains inulin (medium concentration 3.0% w/w) and
xylitol (medium concentration 1.5% w/w) as prebiotic ingredients.
MAKEUP REMOVAL CAPACITY CLINICAL TEST
The study included 15 female volunteers, aged between 18 and 50, to whom commercially
available foundation (Base Liquida Vult HD Alta Cobertura – color 15, Vult, Mogi das
Cruzes, SP, Brazil), blush (Blush Vult – color 12, Vult, Mogi das Cruzes, SP, Brazil),
eyeshadow (Sombra Uno Vult MA01, Vult, Mogi das Cruzes, SP, Brazil), mascara (Máscara
para Cílios Vult 5UP! – black, Vult, Mogi das Cruzes, SP, Brazil), and lipstick (Batom Vult
01 Cereja Cremoso, Vult, Mogi das Cruzes, SP, Brazil) were applied, as shown in Figure 1.
Front and side images were recorded with Visia® (Canfield Scientific, Inc., Parsippany, NJ,
USA) equipment before makeup application (T0), after makeup application (T
makeup ),and

555 Prebiotic Micellar Solution
after makeup removal with a prebiotic aqueous micellar solution (T
removal ).The prebiotic
aqueous micellar solution was applied topically five times with cotton wool on each evaluated
area, and the excess product was removed with a dry, soft fabric. The image analysis
software compares the body of the makeup-excluded area and the body of the adjacent
skin in the three captured images (T0, T
makeup ,and T
removal )and quantitatively calculates
the removal efficiency using percentages. The same analysis is carried out for any colored
products applied to the face. A frontal image of the face was used for eyeshadow, mascara,
and lipstick. For foundation and blush, a side image of the face was used. Statistical analysis
was performed using the Wilcoxon test, a nonparametric statistical test used to compare
two paired or related samples by evaluating the differences between their medians. It is an
alternative to the t-test for data that do not follow a normal distribution.16,17 The groups
studied were considered statistically significant when the p value was less than or equal
to 0.05.
EX VIVO SKIN MICROBIOME EVALUATION
An efficacy test in an ex vivo model was used to evaluate the product’s performance on the
skin’s microbiome. The study was performed at Laboratoire BIO-EC (Longjumeau, France).
To assess the effect of a prebiotic aqueous micellar solution on the growth of the commensal
bacterium Staphylococcus epidermidis (strain CIP 157777, Institute Pasteur, Paris, France) and
the pathogenic bacterium Staphylococcus aureus (strain CIP 4.83, Institute Pasteur, Paris,
France), 12 human skin explants with an average diameter of 12 mm (±1 mm) obtained
from the abdominoplasty of a 44-year-old woman patient were divided into four groups (as
described in the following sections) and maintained in BIO-EC’s Explant Medium (BEM®,
Longjumeau, France), which is a proprietary explant medium, in an incubator at 37°C and
5% CO
2 .
Basal Group (B). This group receives changes in the culture medium, but it is not exposed
to treatment with microorganisms and acts as a control for the sterile skin condition. On
Day 7, the explants are rinsed with phosphate-buffered saline (PBS) to remove potential
nonadherent contaminant bacteria from the surface.
Figure 1. Makeup application guidelines.