To scientifically determine whether a product "suits your skin," measuring your skin's condition with numerical data is effective. Here we introduce three important measurement indicators.
Three Measurement Indicators
1. TEWL (Transepidermal Water Loss)
A direct indicator of barrier function status. Healthy forearm values are 5-15 g/m2/h, rising above 20 when the barrier is compromised.
2. Stratum Corneum Moisture (Corneometer value)
Healthy state is 40-60 AU, dropping below 30 in dehydrated conditions.
3. Sebum Level
The optimal range is 100-200 ug/cm2.
Sensory Feel and Data Don't Always Align
Products that "feel nice" and products that "improve your numbers" do not necessarily match. Silicone-based serums may feel amazing immediately after application, but TEWL may not improve. Conversely, ceramide-based products may feel unremarkable, yet with continued use, TEWL decreases significantly.