Your thinning hair may be due to low body iron, not just ageing and genetics.
Good sources of dietary iron include meat (especially liver), lentils, eggs, dried apricots and wholegrain bread.
Adequate iron status is measured by a simple blood test for serum ferritin (a protein that indicates iron storage levels) and red blood cell number, size and haemoglobin content. While a blood test result of more than 15 µg of ferritin per litre of blood will be indicated as normal by the lab, and hence your GP, hair specialists consider that a much higher value, 70 µg, is needed to prevent hair thinning.
The latest UK government data (National Diet and Health Survey, Department of Health, 2012) shows that over half of all women have serum ferritin levels that are not high enough to prevent hair thinning.
If you have thinning hair, ask your GP for a blood test, and if your serum ferritin levels are below 70 µg per litre, ask for iron supplements and dietary advice.