Although some people embrace the saying “bald is beautiful,” for others, alopecia, or excessive hair loss, can cause stress and anxiety. Some studies have shown that stimulating the skin with lasers can help regrow hair, but the equipment is often large, consumes lots of energy and is difficult to use in daily life. Now, researchers have developed a flexible, wearable photostimulator that speeds up hair growth in mice. They report their results in ACS Nano.