Hydration Series

At first glance, ‘dry’ and ‘dehydrated’ seem like two words to describe the same thing. But when it comes to skincare, they are completely different concerns or conditions with different underlying causes.

What’s the difference between dry and dehydrated skin?

Dry skin is a skin type, but dehydrated skin is a condition that can be experienced by anyone. Dry skin has a lack of oil, or lipids because it produces less sebum than normal skin, and the lack of sebum means the skin is without the lipids it needs to retain moisture and to build a strong barrier to protect against external aggressors.

With dehydrated skin, there’s a lack of water, not oil, in the stratum corneum, which is the top layer of the skin. Dehydration is caused by many external factors, but the most common are weather, environment, diet, and caffeine consumption, all of which can result in diminished water content within the skin.

Dehydrated skin typically looks dull and can show premature signs of aging, like surface wrinkles and loss of elasticity.

You don’t need to have dry skin to have dehydrated skin. Oily and combination skin can be dehydrated as well.

Key causes of dehydrated skin

Outdoor Environment: The harmful rays of the sun can dehydrate the skin since there is water loss from the upper layer of the skin. UVA is the main factor that can affect our skin.

Temperature and humidity changes can really affect the way your skin looks and behaves. Winter is particularly harsh as cold, low humidity air can cause skin to dry out and become itchy, cracked and irritated. Cold air also tightens pores, reduces circulation, and reduces sebum production. Low humidity, hot showers, and central heat also contribute to skin dehydration.

Hot showers and Baths: Hard water contains limestone which can remove water from the skin. Hot showers can also make the skin dehydrated.

Incorrect Skincare: If you’re using products that are too harsh, too light, or you’re using them infrequently, your skincare could be contributing to your dehydrated skin concerns.

Poor Diet: Because obviously we all know lifestyle plays an important role in our skin!

What is TEWL?

Transepidermal water loss, or TEWL, is a term commonly used in skincare, but many people are unfamiliar with what it actually means and why it is so important for your skin.

The skin is comprised of three primary layers: the epidermis, the outermost layer; the dermis or middle layer; and the hypodermis, the innermost layer. When water passes from the dermis through the epidermis and evaporates from the skin’s surface, this is known as transepidermal water loss. 

While TEWL is a process that your skin naturally regulates, certain factors that can damage the skin’s barrier function can also affect TEWL levels. Circumstances such as injury, low-humidity weather conditions and topically applied products that dry out the skin can impact TEWL. This leads to dehydrated skin.

Transepidermal water loss can contribute to a variety of skin conditions, including a more pronounced appearance of fine lines and wrinkles. Although it is a natural process, there are ways that you can help your skin stay moisturized and hydrated. Hydration refers to the water content of the skin, whereas moisturization is the skin’s ability to retain those water molecules. Therefore, your skin needs both elements to maintain desirable levels of TEWL.