The best way to perk up mousy brown hair is to color it, either by adding highlights and lightening it or by darkening it to a richer and more lustrous color and sheen. Brown hair often develops a dull and mousy tone with age, especially when gray hair starts to appear.
As hair becomes dryer and thinner, coloring either at a salon or at home can make a major difference. However, choosing just one color can be counterproductive; it can increase the appearance of age and is also a high-maintenance choice. Instead, mousy brown hair can be covered with a semi-permanent color wash. Adding lowlights, which are streaks of darker color, helps bring a sense of color and texture to longer hair, according to All About You.
When choosing a new hair color, the most flattering color choice for a woman is often the color she was born with; looking at childhood photos can provide some inspiration. Choosing a hair color within one to three shades of the current color is also a good idea so the natural color is not too obvious as it grows out. Color-enhancing shampoos and conditioners can also add moisture and a very minimal amount of color to mousy brown hair.