Nail ridges? whats the cause and what can you do? Nail ridges are raised lines or grooves that run vertically or horizontally across the nails. They can be a natural sign of aging, often appearing as vertical ridges from the cuticle to the nail tip, which are usually harmless. However, horizontal ridges, known as Beau's lines, may indicate underlying health conditions such as nutritional deficiencies, stress, or even more serious issues. In some cases, dehydration, poor nail care, or trauma to t