Does A Humidifier Help With Dry Skin? Yes!

Water is essential for the normal functioning of the skin

The water content of skin is remarkably high - the epidermis (the outer skin layer) contains more than 70% water, while its outermost layer, the stratum corneum has been shown to contain ~15 - 25% water (Warner et al, 1988; Caspers et al, 2001; Caspers et al, 2003).

Adequate hydration of the stratum corneum serves three major functions (Fowler, 2012):

1. it maintains plasticity of the skin, protecting it from damage

2. it contributes to optimum stratum corneum barrier function

3. it allows hydrolytic enzymes to function in the process of desquamation

When the water content of the stratum corneum falls below 10%, scaling on the skin surface becomes visible (Rycroft, 1985).

Learn more: What is Dehydrated Skin?

Low humidity can worsen dry skin

Studies in humans show a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness (Goad et al, 2016).

Indeed, when your skin is exposed to a dry environment, it could be more susceptible to mechanical stress (Engebretsen et al, 2016). 

How does low humidity affect your skin during sleep?

In a study, adult women were exposed to low humidity (30% relative humidity conditions) and high humidity (70% relative humidity) environments during their sleep cycle (Jang et al, 2019).

After 7 hours of sleep-in low humidity, their skin hydration decreased by 24.23%, but there was no significant difference after sleeping in high humidity environment (Jang et al, 2019).

The skin barrier integrity as measured by transepidermal water loss (TEWL) was significantly increased after facial cleansing, following sleep in low humidity environment (Jang et al, 2019).

Furthermore, the sebum level was increased after sleep at low humidity (Jang et al, 2019). 

When sleeping in dry environment, skin hydration decreases but the amount of sebum increases to compensate for skin dryness (Jang et al, 2019). 

What is best humidity level for skin?

It is generally thought that humidity levels within occupied spaces should not exceed 60%, and when levels of humidity fall to around 30% or below, occupants begin to feel thermal discomfort (Goad et al, 2016).

It has been shown that under 30% relative humidity, the eyes and skin become dry, and under 10% relative humidity the nasal mucous membrane becomes dry as well as the eyes and skin (Sunwoo et al, 2006).