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*Address all correspondence to Gabriella Baki, Gabriella.Baki@utoledo.edu
Water Permeability Testing of Nail Polish Films
CLARISSA BARKER, NONGDO BOUGOUMA, MARIAM ABOU-DAHECH,
BRIANA MAKTABI, FRANK PAGANO AND GABRIELLA BAKI
The University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacy
Practice, Toledo, OH, United States (C.B., N.B., M.A-D., B.M., G.B.)
ACT Solutions Corp, Newark, DE, United States (F.P.)
Accepted for publication November 08, 2022.
Synopsis
Nail polish products claiming water permeability, or a breathable characteristic are becoming popular.
However, there are no official testing methods to evaluate whether the nail polish films are water permeable
and to what extent. Common techniques use porous substrates, such as filter paper, which are unrealistic.
The goal of this study was to evaluate the water permeability of three newer and two traditional nail polishes
with seven methods. One- and two-layer films were tested for film uniformity and film structure with
scanning electron microscopy, film thickness, and water permeability with the following methods: water loss
via evaporation, dye leak test, coffee filter test, paper towel test, color bleeding test, and permeability with
effervescent tablet. No strong evidence of water permeation was seen in this study for any of the nail polishes
tested. While nail polish product offerings are becoming more diverse to target different needs, testing
methodologies have a long way to come to accurately portray the performance of products. This study showed
that simple tests often use unrealistic substrates that yield unreliable results.
INTRODUCTION
Nail polish is a cosmetic product applied to the nails to impart color and make the
nails more attractive. Traditional nail polish consists of pigments suspended in a volatile
nonaqueous solvent and diluent blend to which film formers, plasticizers, and suspending
agents are added and tends to be nonpermeable for water. However, a newer category of
products claims to be breathable or water permeable. There are multiple simple studies on
the internet that can be done at home to test water permeability. However, what becomes
apparent after watching some of the videos and reading the test descriptions is that the
substrates are usually porous, such as filter paper, paper towel, napkin, and even hand
towels. Several issues arise regarding these substrates: a porous substrate absorbs some of
the nail polish solvent before it starts evaporating and before the nail polish could form a
homogeneous film of even thickness, which is what occurs on the nail. The film formed
on the porous substrate has an uneven thickness and may have areas where there is very
little film, which can lead to water passing through the polish into the porous substrate.
Additionally, the thickness of the film cannot be measured if the polish is applied to
J. Cosmet. Sci., 74.6, 360–371 (November/December 2023)

361 Water Permeability of Nail Polish
a porous substrate. Ideally, the dry polish film thickness should be equivalent to that
obtained when the polish is applied to the nail. All these point to a lack of having the tests
under controlled, repeatable, and reproducible conditions. The goal of this study was to
evaluate water permeability of three newer nail polishes that claim water permeability on
the label and two traditional nail polishes as controls with seven methods. Additionally,
film structure and uniformity were assessed via scanning electron microscopy.
MATERIALS AND METHODS
MATERIALS
Five commercial nail polishes were tested in this study (Table I) including Sassy +Chick in
shade 946 purchased at a local store (Dollar Tree, Toledo, OH, referred to as Traditional 1 in
this study), OPI Infinite Shine in shade Steel Waters Run Deep (referred to as Traditional 2 in
this study), 786 Cosmetics in shade Shiraz (referred to as Water Permeable 1 in this study),
Orly Breathable Treatment and Color in shade Kiss Me I’m Kind, both purchased from a
local store (Ulta Beauty, Toledo, OH, referred to as Water Permeable 2 in this study), and
Tuesday in Love in shade Sunshine purchased online (Amazon.com, referred to as Water
Permeable 3 in this study). Kroger brand blue food color (water, glycerin, Blue 1, citric acid,
sodium benzoate) was purchased from a local Kroger store (Perrysburg, OH). Deionized
water was provided by the University of Toledo, Health Science Campus (Toledo, OH).
Bounty paper towels were purchased from a local Costco store (Perrysburg, OH) and the
Fresh cup paper coffee filter was purchased from a local Dollar Tree store (Toledo, OH). For
the effervescent test, Alka Seltzer tablets were used (Bayer Consumer Health, Boca Raton,
FL), purchased from a local pharmacy (Walgreens, Toledo, OH).
METHODOLOGY
Film thickness. Film thickness was tested in two different ways. In one method, one coat of
nail polish was applied with the applicator that was part of the original packaging on a
silicone mat and allowed to dry for five minutes. With metal forceps, the film was peeled
off the mat and its thickness was measured using a micrometer (Mitutoyo, Aurora, IL).
Each film was measured in three separate spots. For the two-layer film, the same procedure
was followed with the only difference of using two coats of nail polish instead of one. In the
other method, the nail polish was applied to plastic nails (Kiss, Port Washington, NY).
The thickness of the nail was measured before, with one layer, and two layers of nail polish
with a caliper (Vinca, Valencia, CA). Each sample was measured three times.
Water loss via evaporation. The test was completed using either one or two coats of nail
polish. One coat of each polish was painted with the applicator that was part of the original
packaging on a silicone mat and allowed to dry for five minutes. Approximately 15 mL of
water was poured into a 15 mL centrifuge tube. Using metal forceps, the film was peeled
off the mat and placed over a centrifuge tube ensuring good sealing. The tube was placed
into a stability cabinet for 24 hours at 2 different temperatures (25°C and 45°C). The
weight of the centrifuge tubes was recorded before the test and at 24 hours using a 2-digit
scale (Hogentogler &Co, Inc., Columbia, MD) and the weight difference was calculated to
measure water loss. An open centrifuge tube without any cap, but with the same amount
of water was used as the control. Each sample was measured three times.