If theres one thing that really concerns me, it's thinning hair or hair loss as I get older. I have heard there are some products that can stimulate hair growth for women, but I haven't tried any yet.
There are a few reasons for female hair loss.
Genetics: Some people have a genetic predisposition to hair loss.
Medical Causes: Hormonal problems in women can cause hair loss. Auto-Immune disorders cause hair loss, but specifically causes hair to come out in lumps or patches. There can also be a change in the natural hair growth system that often follows childbirth, crash dieting, surgery, or a traumatic emotional event. Lastly, thyroid disorders, anemia, even chronic illness or the use of certain medications can also cause hair loss in women that is often undiagnosed.
The number one rule of treating hair loss in women is getting the correct diagnosis -- if there is an underlying physical problem it has to be corrected first.
Here is another good source for information on hair loss treatments (second part of the article): Article: Hair Growth & Hair Loss