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You may not have heard the term “transepidermal water loss” before or what it actually means and why it is so important for your skin.

TEWL = moisture loss that moves upward from the dermis through the outer layers of the epidermis.

TEWL is a natural process and is how your skin regulates its own water content. High rates of transepidermal water loss, however, create an impaired barrier function, lacking in moisture, which can make skin feel inflamed, tight, cracked, and itchy. If this water loss is not corrected it can lead to dehydration and speed up the ageing process, increasing the visibility of fine lines, rough texture, and dull appearance.

This process accelerates dramatically at night and can exacerbate existing skin conditions such as eczema, rosacea, and psoriasis; and can become more apparent during the menopausal years.

To understand transepidermal water loss, it helps to first understand the different layers of skin.

The process of renewal and shedding skin takes about 30 days, the amount of time it takes for a cell to be born in the dermis and reach the surface of the skin (epidermis).

The acid mantle is a slightly acidic protective film on the skin made up of sebum secretions, blended with perspiration. When this is in balance, the skin is less vulnerable to damaging attacks by environmental factors (sun, wind, bacteria), and less prone to dehydration.

Other factors that increase TEWL include being in low-humidity climates and using aggressive skincare routines, such as over cleansing or using too many harsh ingredients.

Preventing TEWL

  • Keep hydrated throughout the day
  • Maintain your skin’s microbiome, or ecosystem, to create a healthy skin barrier through effective treatments to revise the skin
  • Use a gentle cleanser and humectants (hydrators), which help to draw moisture to the epidermis
  • Use a humidifier in winter months when low-humid climates occur due to central heating
  • Increase essential fatty acids in your diet

If you feel like you may be experiencing TEWL why not book in for a skin analysis with the Observ 520x to assess your skin and devise a bespoke treatment plan to create a healthier skin!


Please contact Karen Hunter


T: 07539470449