Why is our skin waterproof?

THAT’S THE WHY: It’s an everyday occurrence: you wash your hands, have a shower or go for a swim, and your skin doesn’t let …

THAT'S THE WHY:It's an everyday occurrence: you wash your hands, have a shower or go for a swim, and your skin doesn't let all that water through. Having waterproof skin is pretty useful for protecting what lies within, and also for stopping our bodies from drying out like prunes.

But what is it about the structure of skin that allows it to provide such an effective barrier against water?

A new study has come up with fresh insights about how the organisation of fats in the skin could make it impervious to water.

Researchers took skin scrapings from five male volunteers and froze the samples. Then they sliced ultra-thin sections from them and used a low-temperature electron microscope to look at the matrix of lipids, or fats, in the outermost skin layer, which is called the stratum corneum.


And what they found was an arrangement of stacked bilayers of fatty molecules that had not previously been described in a biological system.

The organisation of the fatty matrix would make it largely impermeable to water and resistant to hydration and dehydration, and it would enable bending of the skin, they report in the Journal of Investigative Dermatology this month.

“The lipid matrix thus meets the barrier needs of skin by being simultaneously robust and impermeable,” says the report.

The findings could have implications for helping to deliver drugs through the skin, according a release from the Karolinska Institute.

“We can now construct computer simulations to help us find out which substances have to be added to different drugs to open up the skin,” says researcher Dr Lars Norlén. “We hope to one day be able to administer regular drugs like insulin and antibiotics this way.”