Run 1Run 2Run 3
LowHigh
Repeatability
Internal acceptance target:
CV ≤ 15%
Three repeated readings under the same standardized conditions.
Why Skin Feel
Matters
Skincare experience begins before efficacy can be perceived.
From first contact, the skin senses richness, weight, spreadability, glide, absorption and after-feel. Together, these tactile cues shape perceived quality, comfort and willingness to continue use.
The Same Formula Can Feel Different
Skin condition
Age
Sebum level
Stratum corneum condition
Application area
Application method
Climate
Temperature
Humidity
Daily environment
A formula that feels heavy in a hot, humid climate may feel appropriately nourishing in a cool, dry environment. Dry and oily skin may also experience the same formula very differently.
Humid / Warm
High Humidity
Higher Temperature
Balanced
Moderate Humidity
Moderate Temperature
Dry / Cool
Low Humidity
Lower Temperature
SKIN SENSORY STANDARD
Why New
Standards Are Needed
Words such as fresh, nourishing, silky and non-sticky are useful, but inherently subjective.
Oil content, moisture or any single device reading cannot fully describe how a product feels on real skin.
FreshNourishingSilkyNon-sticky
SUBJECTIVE LANGUAGE
OUR SCIENCE
FROM SUBJECTIVE FEELING TO MEASURABLE DESIGN
Two Dimensions
of Skin Feel
To make skin feel more objective, comparable and applicable, the A&S research team established two proprietary relative indices.
LFI and PGI are complementary, independent dimensions. They describe sensory character, not better or worse.
LFITMRelative Lipid Film Index
PGITMPredicted Glide Index
What kind of skin feel is suited to which skin, user and environment?
SKIN SENSORY STANDARD
Understanding LFI
Relative Lipid Film Index
LFI estimates relative light-to-rich lipid-film character using light and rich film references.
LFI 1
Light Film
LFI 2
Balanced Film
LFI 3
Rich Film
SKIN SENSORY STANDARD
Understanding PGI
Predicted Glide Index
PGI estimates relative skin glide from device readings calibrated against 1–7 sensory glide ratings. It is a predictive sensory index, not a direct friction measurement.
LOW GLIDESMOOTH GLIDESILKY GLIDE
PGI 1
Low Glide
0–33PGI 2
Smooth
>33–66PGI 3
Silky
>66–100
SKIN SENSORY STANDARD
How We Measure
A controlled test-and-control protocol
The test area and an untreated control area are measured before and after a fixed amount of product is applied and allowed to equilibrate.
Baseline
Test area + untreated control
Oil · Moisture · White · Device-derived elasticityProduct Application
Fixed test area · Fixed dose ·
Standardized spreadingAfter Equilibration
Repeat three readings at a fixed time
SKIN SENSORY STANDARD
From Readings
to Indices
Device readings are converted into two reference-calibrated relative indices.
ΔX% =(Xafter − Xbefore)(Xbefore + 0.01)× 100
CX = ΔX%test − ΔX%control
LFITMRelative Lipid Film Index
LFI =100 × clip(CO − CO,Light)(CO,Rich − CO,Light), 0, 1
PGITMPredicted Glide Index
Ĝ = β0 + βOCO + βMCM + βWCW
PGI =100 × clip(Ĝ − 1)6, 0, 1
β coefficients are established through one-time sensory calibration.
Skin Sensory Standard
Internal Method
Validation
A structured framework for validating repeatability, reference discrimination and sensory prediction.
Reference LightReference Rich
LowHigh
Reference
Discrimination
Confirms that the method differentiates Light versus Rich film references and Low versus High glide references.
Index Trend
Low
High
HighExpert Assessment
Low
High
HighSensory Calibration
LFI is checked against perceived film richness.
PGI coefficients are trained against 1–7 glide ratings and verified by cross-validation.
Schematic Representation · Not Study Results
Acceptance criteria remain provisional until the reference dataset is established.
Skin Sensory Standard
Skin Feel
Map
Two independent dimensions create a clearer picture of how a product feels on the skin.
Rich & Low Glide
Cushioned & nourishing
Rich & Silky
Rich yet silky
Balanced & Smooth
Daily conditioning
Light & Low Glide
Light & fresh
Light & Silky
Light yet refined
Rich Film
LFIRelative
Lipid Film
Index
Light FilmLipid Film
Index
Low Glide
PGIPredicted Glide Index
Silky GlideDesigned to describe sensory character—
not to rank product quality.
Product Index Label
How to Read LFI & PGI
LFI and PGI describe two complementary dimensions of skin feel. Displayed together, they provide an at-a-glance profile of a formula's sensory character.
LFI 2·PGI 3
Balanced Film · Silky Glide
Relative lipid-film character and predicted skin glide.
LFI · Relative Lipid Film Index
LFI 1Light
Light Film
LFI 2Balanced
Balanced Film
LFI 3Rich
Rich Film
PGI · Predicted Glide Index
PGI 1Low Glide
0–33
PGI 2Smooth
>33–66
PGI 3Silky
>66–100
A Sensory Profile—Not a Performance Score
Unlike SPF or PA, LFI and PGI do not indicate protection, efficacy or product quality.
They describe two independent dimensions of sensory character under standardized A&S test conditions.
LFI levels are shown qualitatively; numerical classification thresholds remain provisional.
A&S proprietary classification. Product profiles should be compared only when measured using the same standardized protocol.
Application Scope
Where LFI &
PGI Apply
Designed for topical products that leave a measurable sensory profile on the skin.
Serums & Essences
Lightweight finish · rapid spread
Lotions & Emulsions
Balance of film and glide
Creams & Balms
Richness · cushion · residual feel
Facial & Body Oils
Lipid presence · mobility
Sunscreens & Primers
After-feel · smooth application
Body, Hand & Massage Care
Slip · comfort · lasting film
Rinse-off Cleansing
In-use glide · post-rinse feel
Mist & Spray
Fine dispersion · weightless feel
One Framework. Different Sensory Targets.
LFI and PGI describe how a formula feels—not whether one product type is better than another.
For rinse-off cleansing, in-use glide and post-rinse skin feel should be evaluated separately. Test site, dose, water exposure, rinsing conditions and equilibration time must be standardized.
Masks, scalp or hair products, and color cosmetics require protocols adapted to their intended use.