Measuring Trans-Epidermal Water Loss (TEWL)
We measure how much water vapour your skin releases per unit time. TEWL is the gold-standard marker for barrier integrity. Watch how we take an in-clinic TEWL reading.
Live measurement (real example)
This clip shows our standardised TEWL test in action. We log vapour flux (g/m²·h) and compare it against normative ranges for your skin type and age.
Barrier metrics at a glance
Illustrative values shown. We personalise ranges by facial site, season and tolerance, and interpret metrics together rather than in isolation.
How it works
We use a closed-chamber probe (e.g., Tewameter) that measures the vapour gradient between skin surface and air. The device logs flux continuously for a short duration under controlled conditions.
- Ambient conditions (temperature, humidity) logged
- Probe held gently and consistently at each site
- Multiple measurements averaged for reliability
Interpreting your reading
Higher TEWL = compromised barrier (more water escaping). Lower TEWL = stronger barrier control. We use this to refine moisturiser choices, barrier repair routines and treatment planning.