Forbes reports, researchers at the University of North Carolina and Columbia University have designed microneedle patches that use needles to inject small amounts of chemicals and drugs into the skin. What was inside the needles was a browning agent, something that converts white fat to brown fat.

They test-drove the patches on obese mice, placing it on just one side of the mice’s body. They were able to reduce the fat on the side of the body with the patch by 20%.

For all intents and purposes, brown fat is more like traditional “baby fat.” White fat calls have a single large oily droplet inside, while brown fat cells contain several droplets as well as mitochondria that give the cells a brown color and “act as mini-furnaces” to burn those tiny oil droplets to generate heat. Basically, they’re used to keep babies warm before they’re able to shiver on their own.

Brown fat typically disappears with age. However, researchers are attempting to bring it back with the patch, ultimately leading to more fat being burned and love handles disappearing. For now it’s just a solution for mice, but in the future it could be used on humans as well.