Are you losing more hair than usual? If so, you might have a vitamin D deficiency.
The human body synthesizes this vitamin directly from the sun. But since not everyone is lucky enough to live in a sunny area, most of us often have a slight vitamin D deficiency.
If you think this might apply to you, ask your doctor for a prescription or increase your consumption of fatty fish like salmon, herring or sardines. Fish also provides us with Omega 3's, which make your hair shiny and soft.