The glycerin (or glycerol) found in moisturisers typically comes from vegetable-based oils. Glycerin is a substance found naturally in the skin where it helps attract and retain water from the deeper skin layers, thereby hydrating and moisturising the skin1.
Glycerin is widely used in topical products and has been found to support skin recovery after induced chemical irritation. In such cases, glycerin is shown to immediately increase the water-holding capacity of the skin, which then in turn promotes recovery of the skin barrier (3).
HelloSkin’s experts were unable to find any scientific data or clinical trials regarding the use of glycerin in people with psoriasis.
In dry skin conditions, including psoriasis, water loss from the upper skin layer is linked to a reduced skin barrier function, which may be worsening the disease symptoms (2).
Maintenance of skin hydration and elasticity in the outer layers of the skin has been shown to involve specific water channels, that transport water and glycerin in and between the skin cells (4). Genetically modified mice without these specific water channels show reduced skin hydration and elasticity, which is corrected after topical or systemic application of glycerin (4). This highlights the importance of these water channels as well as glycerin in healthy skin.
Importantly, in psoriatic lesions these water channels are found mislocated in the skin cells which makes them unable to properly transport water and glycerin (5). It is therefore likely that the transport through these channels is compromised in the specific skin cells called keratinocytes in psoriatic plaques leading to dry skin (6).
The concentration of an ingredient is important for its efficacy, and therefore products containing the same ingredient may not necessarily have the same effect as in the studies mentioned above.
Updated: July 2017