Women experience hair loss and thinning for a number of different reasons. A trip to your doctor or dermatologist might help you find answers as to why. If it's not medically related, there might be things you can do to stop your hair from thinning or at least slow it way down.
Start with eating more protein. Women generally need about 1 gram of protein for every kilo of body weight, which can seem like a lot. For an average-sized woman, that can mean two chicken breasts or four eggs or three cups of lentils every day.