The Balancing Act of "No Tightness / No Fake Slip": Subjective and Objective Evaluation of Post-Cleansing Skin Feel

I. Two Complaints, Two Extremes, the Same Formulation Challenge

Consumer feedback on makeup removers often falls into two diametrically opposed complaint categories:

Type A Complaint: "My face feels tight after cleansing, like the moisture has been sucked out; I need to apply moisturizer immediately." Type B Complaint: "It feels artificially slippery after use, like there's still a layer of something left on my face; it doesn't feel clean."

The root causes of these two complaints appear contradictory, but they actually point to the exact same formulation design proposition: the precise control of post-cleansing skin feel. This is not merely a matter of subjective perception, but a technical dimension that can be systematically quantified and consciously designed by formulation engineers.

In the current global personal care market, where consumer experience is increasingly mature, one of the most significant shifts between 2024 and 2025 is the integration of hydration and skin barrier topics into a single focal point. New products frequently focus simultaneously on high-efficiency moisturization and barrier improvement, recognizing the deep connection between the two for skin health and comfort. Reflected in testing, experts now simultaneously measure hydration (via stratum corneum capacitance) and TEWL reduction values to confirm overall skin functional improvement.

This means that the brand's evaluation requirement for "how the skin feels after makeup removal" has escalated from "whether consumers say it's good" to the scientific context of "what instruments can measure."

II. The Physiological Root of "Tightness": The Loss of NMF

The tightness felt after makeup removal is not a consumer's psychological illusion, but a phenomenon with a clear physiological mechanism.

The stratum corneum contains a class of water-soluble small-molecule mixtures known as Natural Moisturizing Factors (NMF), primarily composed of amino acids and their derivatives (PCA, urocanic acid), lactic acid, urea, and inorganic salts. NMF acts as the "built-in moisture-retaining sponge" for corneocytes, maintaining the flexibility and hydration state of the stratum corneum through hygroscopic and water-locking mechanisms.

Research shows that common skincare habits (including bathing and using cleansing products) affect the water-binding balance of amino acids in the upper stratum corneum. Soluble NMF is significantly reduced in dry skin and is heavily washed out in the superficial stratum corneum of skin exposed to routine bathing or cleansers, and the recovery of the stratum corneum follows a slow and complex kinetic process.

Further research data shows that within 0.5 hours after forearm skin is soaked for 10 minutes, quantitative analysis of sequential tape-stripping samples via HPLC revealed a significant drop in NMF levels; NMF basically recovers at 4 hours. However, stratum corneum hydration values (measured by the Moisture Accumulation Rate, MAT) remain at low levels 0.5 hours post-soaking and stay low even after 4 hours.

For makeup removers, this mechanism implies:

• Makeup removers with excessively high surfactant concentrations (>8% total surfactants) will over-strip the NMF and lipids of the stratum corneum while cleansing makeup, causing stratum corneum hydration to remain persistently low for hours after cleansing, resulting in a tight feel.

• Pure aqueous makeup remover cotton pads (without humectants): The dual action of mechanical friction and water evaporation makes them virtually "tightness-manufacturing machines."

• Mild low-concentration surfactants + appropriate polyol humectants: While effectively removing makeup, polyol humectants can instantly compensate for the hydration drop caused by NMF loss, achieving a "moisturized immediately after cleansing" user experience.

III. The Formulation Root of "Fake Slip": Film-Forming Residue

Opposite to tightness is "fake slip" (artificial slip)—the skin surface feels very smooth, but this slipperiness is unsettling because it comes from a layer of ingredient residue, not the skin's actual state.

The main ingredient sources causing "fake slip":

1. High Concentration Glycerin (>5%): As mentioned earlier, excessive glycerin forms a hygroscopic film on the skin surface, resulting in a significant greasy/slippery feel. Consumers experience the illusion that "the makeup is removed, but there's still stuff on my face."

2. Residue from High-Molecular Film-Forming Thickeners: Carbomers (after neutralization) and polyacrylates, after evaporating on the cotton pad, form a lightweight polymer film on the skin surface. This film brings short-term tactile "smoothness" but interferes with the penetration of subsequent skincare products and causes "pilling" during skin friction.

3. Residue of Surfactant Micelles: High concentrations of non-ionic surfactants (e.g., Polysorbate 20 >5%) in the formula, after evaporating on the skin, leave remaining surfactant molecules aggregating to form a perceptible "slippery film" rather than genuine skin care.

A review study published in the International Journal of Cosmetic Science in 2024 pointed out: in sensory attributes, the "After-feel" stage—which includes residue perception and slipperiness—has a higher correlation with tribological data than with rheological data. This means "fake slip" is essentially a physical phenomenon of an abnormally reduced surface coefficient of friction, which can be objectively quantified using a Tribometer.

IV. Subjective Sensory Evaluation: How to Standardize the Subjective Matter of "Skin Feel"

Consumer terms like "tight," "fake slip," "refreshing," and "smooth" are subjective perceptual descriptions, but in professional sensory evaluation systems, these terms are translated into quantifiable metrics.

In cosmetic sensory evaluation, tactile perception is divided into three stages: first, tactile variables related to product compression, flow, and deformation (e.g., firmness, greasiness, slip, waxiness, paste-like feel, spreadability); subsequently, the quality perception dimensions experienced by the user (e.g., silkiness, velvet feel, stickiness, uniformity); and finally, the user's perception of the residue left on the skin after application and massage.

For the makeup remover category, professional sensory evaluation typically adopts the following methods: Patent literature reveals a standardized subjective evaluation method for the tactile feel of makeup removal products: 10 trained female expert panelists apply each cleansing formula to a cotton pad, wipe the made-up face, and respectively give a 5-point sensory score for the following three dimensions: (1) Fresh Feeling after wiping: 5 = very refreshing, 1 = no refreshing feeling at all; (2) Friction Feeling after wiping: 5 = no friction feeling at all, 1 = strong friction feeling; (3) Absence of Sticky Feeling after wiping: 5 = no stickiness at all, 1 = strong stickiness. The total scores of the ten panelists constitute the formulation's sensory profile.

More systematic sensory evaluation schemes will introduce on this basis: Descriptive Analysis (structured scoring of specific attribute intensities by a trained panel), Time-Intensity Testing (measuring how sensory perception changes over time, e.g., "the intensity of tightness 15 minutes after makeup removal"), and Consumer Acceptance Testing (collecting subjective data on target consumers' product preference and usage intention). These data are usually quantified using Likert scales, category scales, or Visual Analog Scales (VAS), and the significant differences between products are analyzed through statistical methods such as ANOVA.

V. Objective Instrumental Evaluation: Translating Sensory Data into Scientific Evidence

The limitation of subjective sensory evaluation lies in large individual differences, high costs, and inability to be used for claim substantiation. Objective instrumental measurements can translate "tightness" and "fake slip" into quantifiable, reproducible data, forming the scientific basis for efficacy claims.

1. Stratum Corneum Hydration Measurement (Corneometer)

The Corneometer quantifies the moisture-retaining state of the skin surface after makeup removal by measuring the capacitance value of the stratum corneum. Experts now simultaneously measure hydration (via stratum corneum capacitance) and TEWL reduction values to confirm overall skin functional improvement, which has become the standard testing combination for 2024–2025.

Application in Makeup Remover Evaluation:

• Baseline measurement (pre-cleansing) → 5 mins post-cleansing → 30 mins post-cleansing → 2 hours post-cleansing.

• The recovery curve of hydration post-cleansing directly corresponds to the consumer's subjective experience of "the speed at which tightness subsides."

• Qualification Standard Reference: Hydration recovering to >90% of the baseline at 30 mins post-cleansing basically eliminates the feeling of tightness.

2. Transepidermal Water Loss (TEWL) Measurement

TEWL (g·m⁻²·h⁻¹) is the core non-invasive indicator for assessing skin barrier integrity. Normal TEWL reference values for healthy adult facial skin vary depending on the measurement site and device type; forehead values are usually slightly higher than the cheeks. Clinical studies published in 2024–2025 used open, closed, or condensation chamber devices for measurement, with results cross-validated against each other.

An elevated TEWL value indicates exacerbated barrier damage, meaning the formulation's surfactant system is damaging the stratum corneum; an ideally gentle makeup remover should restore TEWL to within ±10% of the baseline within 1–2 hours after use.

3. Coefficient of Friction Measurement (Tribometry)

A Tribometer quantifies the coefficient of friction (μ) on the skin surface by applying a standard load and measuring the resistance to probe movement. An abnormally low coefficient of friction (μ < 50% of the normal skin value) corresponds to the "fake slip" described by consumers—this is the objective quantitative evidence of film-forming residue.

VI. The Landing Point of Brand Value: Sensory Experience Can Be Designed and Must Be Validated

In today's high-performance skincare market, texture is a key design parameter that directly affects product acceptance and perceived efficacy. Sensory characterization translates subjective tactile feel into quantifiable data through trained panels, enabling cosmetic scientists to engineer emulsions for specific tactile performances, covering attributes such as spreadability, slip, cushioning, resistance, and after-feel. This approach links formulation structure to tactile performance, supporting stability optimization, claim substantiation, and consistent consumer experiences.

"No tightness / no fake slip" should not just be a formulation goal for formulators; it should become a product differentiation advantage that can be measured, proven, and claimed. This is where brand product power and OEM technical capability truly land in the market.

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