Blood samples have always been regarded as efficient indicators of health, but with new applications of biometric skin patches, it turns out sweat is as well. Researchers at Northwestern University have discovered that sweat contains a significant amount of health information, from electrolyte content to biometric stats.

Sweat, or perspiration, is made up of water, salt, ammonia, urea, and sugar. Each person is born with roughly 2 to 4 million sweat glands, all of which become active after puberty. Sweat is easy to produce and collect, and is something that every human can create. Because of this, sweat can serve as a simple and plentiful medical sample source that doctors can collect quickly and non-invasively.

To utilize this non-invasive form of biometric exploration, the researchers at Northwestern University came up with the idea of a sweat-absorbing patch. This patch is able to take samples of sweat from the user and relay information back in a matter of seconds. Completely battery and electronics-free, this patch has the potential to change the way biometrics are tested, worldwide.