Topographical wrinkle patterns caused by prolonged human hand immersion in water are repeatable and consistent at different timepoints, according to new research by Binghamton University scientists.
Images of topographical skin wrinkles overlaid on each other from the two different time points 24 h apart, with opacity levels of (A) 0%, (B) 50%, (C) 100%. Image credit: Guy German.
A couple of years ago, Binghamton University researcher Guy German published research about why human skin wrinkles when you stay in the water too long.
Received wisdom held that the water swelled your skin and made your fingers wrinkly, but little to no research had been done to prove that.
What the researchers found is that blood vessels beneath the skin actually contract after prolonged immersion, and that’s where the wrinkles come from.
The new study shows that the topography patterns remain constant after multiple immersions.
“Blood vessels don’t change their position much — they move around a bit, but in relation to other blood vessels, they’re pretty static,” Dr. German said.
“That means the wrinkles should form in the same manner, and we proved that they do.”
The scientists put subjects’ fingers in water for 30 minutes, taking photos and then repeating the immersion under the same conditions at least 24 hours later.
By comparing the images, Dr. German and his colleague, Rachel Laytin, found the same patterns of raised loops and ridges after both immersions.
“We also made an interesting side discovery,” Dr. German said.
“We’ve heard that wrinkles don’t form in people who have median nerve damage in their fingers.”
“One of my students told us, ‘I’ve got median nerve damage in my fingers.’ So we tested him — no wrinkles!”
As much fun as it was to figure out something a child asked, this new study also could have real-world applications in forensics, such as fingerprinting at crime scenes and identifying bodies found after prolonged water exposure.
“My father, a retired U.K. police officer, faced some of these challenges during his law enforcement career,” Dr. German said.
“Biometrics and fingerprints are built into my brain. I always think about this sort of stuff, because it’s fascinating.”
The findings appear in the Journal of the Mechanical Behavior of Biomedical Materials.
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Rachel Laytin & Guy K. German. 2025. On the repeatability of wrinkling topography patterns in the fingers of water immersed human skin. Journal of the Mechanical Behavior of Biomedical Materials 165, 106935; doi: 10.1016/j.jmbbm.2025.106935
