What is TEWL and how we measure it?


Water is constantly evaporating from the skin which is part of the important body’s metabolism. The amount of water (Transepidermal Water Loss – TEWL) is expressed in g/h/m². As soon as the barrier function of the skin however is slightly damaged, the water loss will increase (even with smallest damages invisible to the human eye). Its measurement is an indispensable parameter for the evaluation of the water barrier function of the skin and a basic measurement in all kind of applications for topical applied products.

The C+K Tewameter® has always been working based on the “open chamber” measurement, a method which is acknowledged as the best way to asses this parameter*.

The “open chamber” measurement method is the only method to assess the TEWL continuously without influencing its micro environment.

Inside the probe of the Tewameter® in a hollow cylinder, there are sensors to measure relative humidity and temperature.

The Tewameter® probe measures the density gradient of the water evaporation from the skin Δc which is proportional to the TEWL.


Our available TEWL probes:


  • Tewameter® TM Hex: The ultimative TEWL measurement with one head (NEW)
  • Tewameter® TM 300: Former model of TM Hex
  • Tewameter® TM Nano: Ultra-Small TEWL Measurement Probe for Special Skin Sites
  • Tewameter® Triple TM 330T: TEWL measurement probe with three flexible measurement heads 
  • Invitro Tewameter® VT 310: TEWL measurement directly on Franz cells
  • Tewitro® TW 24: TEWL measurement on up to 24 cultured skin wells simultaneously.
equipment and software for various hair & skin research
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Tewameter® probe TM Hex NEW!

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Tewameter® Probe TM 300

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Tewameter® probe TM Nano

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Tewameter® Probe Triple TM 330T

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Invitro Tewameter® VT 310

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Tewitro® TW 24