Levels is an American metabolic health company built around a small sensor worn on the back of the upper arm. The company does not manufacture that sensor. It packages continuous glucose monitors made by medical device firms with an app, lab panels and coaching.

How it works

A thin filament sits just under the skin, coated so that it reacts with glucose in the fluid between cells. The reaction produces a faint electrical current that rises and falls with blood sugar. The app turns those readings into a line and sets it beside logged meals, workouts and sleep, so a spike can be traced back to something specific.

Key considerations

Each sensor expires after about two weeks and the app runs on a subscription, so the cost carries on well past the first month.