Nano brows are a semipermanent makeup treatment for the eyebrows to mimic the look of thick natural brows. The treatment can fill in hair loss and sparse patches and modify the shape of brow arches. Tessa Hoang is a permanent-makeup artist who specializes in the nano-brow technique. She works with clients who experience extreme hair loss from medical conditions and diseases. Typically nano brows will last 1 1/2 to two years, but they can last longer with touch-ups. | Insider Beauty