From Dryness to Optimal Hydration —Track TEWL with precision using the VapoMeter®️
- Emma Danciu
- Nov 1
- 6 min read
The skin is the body’s largest organ and serves as a dynamic barrier between the internal environment and the outside world. One of its most vital functions is to prevent excessive water loss — a process quantified as Transepidermal Water Loss (TEWL).
TEWL represents the passive diffusion of water vapor through the epidermis to the skin surface, where it evaporates into the atmosphere. Closely related, the evaporation rate describes the quantity of water evaporating from the skin surface per unit of time. Together, these parameters provide a sensitive and non-invasive measure of the skin barrier’s integrity and functionality.
The measurement of TEWL is universally recognized as a gold standard for assessing skin barrier function. A healthy stratum corneum maintains optimal hydration and lipid organization, ensuring low levels of water loss. When the barrier is compromised — due to environmental stress, dermatological conditions, or cosmetic treatments — TEWL levels rise significantly.
High TEWL values indicate increased permeability and barrier disruption while Low TEWL values reflect an intact, well-functioning epidermal barrier.
By quantifying these changes, TEWL provides direct, quantitative insight into the skin’s physiological status, allowing early detection of barrier impairment even before visible symptoms appear.
Environmental stressors — low humidity, UV radiation, pollutants, and temperature extremes — strongly influence skin water balance. Continuous or repeated TEWL measurements help:
Quantify the impact of environmental exposure on barrier integrity.
Identify occupational risks, such as in healthcare or manufacturing, where frequent hand washing or solvent exposure compromises the barrier.
Develop strategies for preventive skincare and barrier protection in sensitive populations.
By correlating TEWL variations with environmental parameters, researchers can understand how external conditions affect skin physiology and develop more resilient skincare solutions.
The Evaporation Rate is a complementary parameter. While TEWL focuses on water diffusion through the epidermis, the total evaporation rate encompasses both transepidermal and surface water loss (e.g., from sweat or exudate). Monitoring evaporation rate is particularly important when:
Evaluating hyperhidrosis, sweating response, or thermoregulatory function.
Assessing post-occlusive or wound healing environments where both barrier recovery and surface moisture interact.
Studying cosmetic applications or film-forming products that modulate skin microclimate.
By distinguishing between TEWL and total evaporation, researchers obtain a more nuanced understanding of skin water dynamics.
Understanding and Managing Skin Disorders
Many dermatological and systemic conditions are associated with altered TEWL and evaporation dynamics. For instance:
Atopic dermatitis, psoriasis, and ichthyosis show elevated TEWL due to impaired lipid synthesis and disrupted corneocytes cohesion.
Diabetes, aging, and chronic inflammation alter epidermal water balance, leading to dryness and micro-cracking.
Wound healing and post-procedure recovery (e.g., after laser, peel, or micro-needling) can be objectively monitored by following TEWL trends.
Measuring TEWL thus provides clinicians and researchers with an objective biomarker for disease severity, treatment efficacy, and skin recovery processes.
Evaluating Cosmetic and Dermatological Treatments
In cosmetic science, TEWL measurement is fundamental for evaluating product performance and skin compatibility. Moisturizers, emollients, occlusive agents, or barrier creams are often designed to reduce water loss. Quantifying their effects through TEWL monitoring allows:
Objective verification of claims such as “improves skin hydration” or “restores the skin barrier.”
Comparison of different formulations and active ingredients under controlled conditions.
Optimization of product efficacy during R&D and quality control.
Similarly, TEWL is used to assess potential irritation or barrier damage caused by topical formulations, surfactants, or environmental exposures.
We know that measuring the skin barrier’s function accurately is essential in dermatological research, cosmetic testing, and clinical evaluation. Therefore, you need to use the most performant and reliable tool to assess Transepidermal Water Loss.
Traditional open-chamber methods can be sensitive to ambient conditions and cumbersome in use.
Challenges with Traditional TEWL Measurements
Conventional open-chamber devices measure moisture evaporation directly from the skin surface. However, they are:
Highly sensitive to airflow and environmental fluctuations,
Often limited to laboratory use,
Time-consuming due to stabilization requirements,
Inconvenient because measurements are affected by device orientation
Such factors can compromise data consistency and limit their practicality in field studies or multi-center trials.
That’s where the VapoMeter® redefines the process — offering a closed-chamber, portable Instrument that provides precise and instant TEWL readings in any position, anytime, anywhere.
Track TEWL With The VapoMeter®
The VapoMeter®: Delfin’s Closed-Chamber Innovation
The VapoMeter® solves these limitations with Delfin’s patented closed-chamber technology.
It works by momentarily sealing the measurement area and monitoring the rate of humidity increase inside the chamber — delivering in seconds a true, reproducible TEWL value and evaporation rate as g/m²h.
At the heart of the VapoMeter® lies a highly sensitive humidity sensor housed within a cylindrical measurement chamber. During measurement, the chamber is sealed against the skin or other surface, remaining unaffected by ambient airflows.
The sensor continuously monitors the increase in relative humidity (RH) inside the chamber, from which the evaporation rate (g/m²h) is automatically calculated. Between measurements, the chamber undergoes passive ventilation, with the ventilation period precisely controlled by the system.
✔️ Key Features
🛡️ | Closed chamber — eliminates external airflow interference. |
📡 | Portable and wireless — ideal for laboratory and in-field studies. |
⏱️ | Fast and reliable — results in less than 10 seconds. No daily calibration procedure required. |
🌐 | Versatile applications — suitable for all body sites and skin types. Can be used for in-vivo (with 2 adapters), and in-vitro (with 5 adapters for Frantz Cell) user applications. |
🍃 | Natural Integrity — Does not change skin’s natural behavior, no artificially created climate change, no de-icing. |
📄 | Study approved — comes with a dated Calibration Certificate for reliability. |
💾 | Delfin DMC software compatibility — for data storage. |
Why Choose the VapoMeter®?
Unlike other TEWL instruments, the VapoMeter® combines scientific accuracy with unmatched convenience. Its closed design minimizes external variability, ensuring reproducibility across operators and sites — a crucial advantage for multi-center studies and regulatory testing.
When connected to the DMC software, researchers can visualize, compare, and export results seamlessly, making it a complete solution for modern skin barrier evaluation.
Example of Measurement with the VapoMeter®
A moisturizing disinfectant used on hands daily for 8 weeks
4 measurements performed during the period
91 with healthy skin, 35 with skin disease
As the VapoMeter® is a versatile instrument, it can be used in-vivo to evaluate the skin’s barrier integrity and hydration, as well as in-vitro on skin explants, reconstructed skin models, and surface replicas for research or product testing.
It is also useful for measuring hyperhidrosis and assessing nails to evaluate nail plate permeability and barrier performance.
Additionally, it can be applied in animal health and zoology to assess skin barrier function, hydration, and overall welfare across species.
Conclusion
Measuring transepidermal water loss and evaporation rate provides an essential window into skin physiology. These parameters translate invisible biochemical and structural processes into measurable values that reflect hydration, integrity, and environmental adaptation.
Whether used in clinical dermatology, cosmetic research, occupational health, or fundamental skin science, TEWL and evaporation rate measurements remain indispensable for understanding, protecting, and optimizing the skin barrier — the first and most vital shield of human health.
The VapoMeter® brings precision, speed, and portability — empowering researchers and clinicians to assess the skin barrier with confidence, wherever their studies take them.
Discover Delfin’s full range of skin research instruments at Skinlabs and see how advanced measurement tools can elevate your next research. |
Publications
J. Soc. Cosmet. Sci. Korea
Gaewon Nam*†. Stratum Corneum Exfoliation Effect with Hydroxy Acid according pH. http://dx.doi.org/10.15230/SCSK.2016.42.4.413
Journal of Dermatological treatment
Da-Hyun Kanga, Sang-min Choia, Yoonsung Lee, Man S. Kim, Bark-Lynn Lew and Soon-Hyo Kwon. Postoperative risk assessment of post-inflammatory hyperpigmentation and the efficacy of delayed prevention following 532 nm Q-switched Nd:YAG laser treatment of solar lentigines: a randomized controlled study.
Journal of Dermatologic Science and Cosmetic Technology
Yucong Wanga , Shuting Lia , Yunfei Aib,⁎ , Stephen Lynchc , Nada Baalbakid , Xianghua Zhangb , Xiaofeng Hea , Xiaoqing Huange , Andrew Steela , Kungchi Hsua , Hequn Wanga. Evaluating the effect of moisturizers containing endogenous lipids on skin barrier properties. https://doi.org/10.1016/j.jdsct.2024.100037
Molecular Pharmaceutics
Maja Railic, Abina M. Crean, and Sonja Vucen. Unravelling Microarray Patch Performance: The Role of In Vitro Release Medium and Biorelevant Testing.
Biomedicines
Hyo Sang Kim , Myeong Hwan Kim , Byeong Yeob Jeon , You Kyung Jang , Jeong Ki Kim , Hyun Keun Song * , KilSoo Kim. Deep Sea Minerals Ameliorate Dermatophagoides farinae or 2,4- Dinitrochlorobenzene-Induced Atopic Dermatitis in NC/Nga Mice.
https://doi.org/10.3390/biomedicine13040861
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