Continuous chemistry, smarter care: wearable biosensors are transforming health

From ancient diagnostic practices to at-home tests and smartwatches, humans have continually sought clearer insight into their own physiology. The problem is that the body rarely provides tidy readouts on demand. Most of the time, we get a snapshot, like a blood test at the doctor’s office, and then we infer what is happening between tests. Wearables are the newest step in our long history of self-measurement, and wearable biosensors turn the body’s chemistry into a continuous stream of information usable in real time. In this article, we introduce wearable electrochemical biosensors and explain the basic workflow shared by most systems: accessing a body fluid, recognizing a target molecule, generating a measurable change, and converting it into an electrical readout. The challenge is durability in the real world: wearables must stay selective and stable in complex biofluids on a constantly changing body and at the skin interface. We examine on-skin and subdermal sensing, highlighting minimally invasive tools such as microneedles that enable practical long-term monitoring. Taken together, we get a shift from single data points to trends, delays, responses to meals and exercise, and the slow drifts that can matter most for understanding our health.