Over the past few years, many people have added a microcurrent device to their skincare regimen, hoping it will be anti-aging, produce collagen, sculpt facial muscles and improve skin texture.

The first time I tried microcurrent was in a brightly lit store surrounded by 50 other beauty writers. The year was 2018, and NuFace and FaceGym, then using a newfangled technique, had teamed up ...