Imagine managing diabetes without painful daily injections. That might soon be possible, thanks to a breakthrough from scientists in China who developed a skin cream that delivers insulin through the skin.

They used a clever polymer called OP that changes its properties based on the skin’s natural acidity. On the skin’s surface, it’s positively charged and binds to skin fats; deeper down, where the pH is more neutral, it releases its insulin cargo.

In experiments on diabetic mice and minipigs, applying this OP–insulin complex brought blood sugar down to normal levels within 1–2 hours — and kept it stable for about 12 hours, without signs of irritation or inflammation.

Even more exciting: once inside the body, the insulin accumulates in glucose-regulating tissues like the liver, fat, and muscles — working just like injected insulin, but with a gentler, more sustained effect.

The research, published in Nature, could mark the beginning of a needle-free era for insulin and other protein-based treatments. Scientists are already thinking about applying this technology to other therapeutics.