Wash your hair as little as hygienically possible. The oils your scalp produce actually strengthens your hair. Also drink a lot of milk and try protein supplements it'll help Nourish your scalp for healthier hair
if it is not your age my friends who have same problem are caused due to
1 stress solution: meditation everyday
2 liver problem (his is due to fatty liver) please go check with your doctor
3 allergy to chemical in shampoo: try using shampoos made of natural ingredients
I am allergic to amla once i used a amla shampoo my one hair went white but when i stopped none is going white
Have you had your thyroid checked? They other suggestions are wonderful, but you should also have your thyroid checked while getting the tests for Crohn's disease. It makes sense to check for Crohn's disease, because if it's not that one, if there is any detectable autoimmune disease there are basic blood tests that discover this much. They don't always signify which autoimmune illness it is, and usually they're looking into the possibility of RA or Lupus when they're looking into this. If the ANA and the SED rates are "normal", though, they don't look any further. So, definitely have them look into the thyroid while you're at it. Again, with the thyroid, even if there is a possibility of minor thyroid issues, if the TSH is "normal", they don't look into this any further. Nope, not unless you push them to do so. Even then they might not test the free T3 and free T4, which can actually be off even if the TSH tests normal.
Check for food allergies or other causes of malabsorption or malnutrition. Check for bowel diseases like Crohn's disease. Apply olive oil to dry hair and wrap in a towel for an hour before your usual shampoo. Try Loreal Vive Pro shampoo (yellow bottle shown in center here) http://www.lorealparisusa.com/_us/_en/default.aspx#/?page=top{userdata//d+d//|diagnostic|main:brandpage:vivepro|media:_blank|nav|overlay:_blank}
Try Osteobyflex Nutrajoint in powder form. It's sold at Walmart for about $20 and it lasts quite a while. Use it every day til it's gone. I'm 56 and have thick shiny hair just from using this stuff. And by the way, use 1/2 of the scoop in your favorite juice. Good luck!
P.S. If it works, you'll need to use it forever. As soon as you quit your hair gets dull and brittle again! :(