Renpho is a wellness company making connected body scales, massage devices and fitness tools. Its smart scales are used barefoot and send weight and estimated body composition results to the Renpho Health app.

How it works
Pressure sensors measure weight. Metal plates under the feet send a very small electrical current through the body and measure tissue resistance. Water rich muscle conducts the current differently from fat. Software combines that resistance with personal data to estimate body fat, muscle, water and metrics.

Key considerations
Most Renpho scales measure through the legs and use equations to estimate the rest of the body. Hydration, meals, exercise, skin temperature and foot placement can shift results. Bone mass and visceral fat figures are calculated estimates, not direct measurements.