DHT causes the growth cycle of hair follicles to shorten, which in turn reduces the size of the hair shaft. Increasingly narrower hair is grown, sometimes as fine as fluff, and in more extreme cases, there is complete hair loss in that area. In women, estrogen usually counteracts the effects of testosterone.

But when women go through menopause, or suffer hormonal imbalances, the reduction in estrogen can lead to female pattern baldness. Fortunately, this is not as drastic in its hair loss effects as male pattern baldness. Instead the hair tends to thin, and the crown parting becomes wider.

But a very interesting study by L'Oreal has linked an iron deficiency to hair loss, in both men and women. This was a placebo controlled, double blind study in which 13,000 healthy men and women took a supplement, and had the ferritin (iron) levels in their blood measured and cross referenced with information on their hair loss. The results showed not only a link between hair loss and iron deficiency, but they were able to estimate the risk of hair loss in a certain level of iron deficiency.

For example, women whose blood ferritin levels dropped from a normal 70g/l to 40g/l, had a 28% higher chance of severe hair loss. The post menopausal women in the study who had severe hair loss all had much lower levels of iron than the women who didn't have severe hair loss. The problem with iron supplementation, however, is that excess iron builds up in the body's tissues and becomes toxic.

It has been associated with an increased risk of developing chronic illnesses. Iron levels can be tested by a doctor, so if hair loss is a concern, its best to get your iron levels tested first before taking iron supplements. Other potential causes of hair loss - or at least, contributing factors are stress and poor hair care practices.

Not brushing hair regularly, or washing it regularly, can affect the normal hair growth cycle. When hair that is naturally at the end of its life cycle is removed through brushing, it allows another hair to grow underneath it. Regular brushing naturally removes dead hair that is ready to fall out.

Not removing that hair means new growth cannot occur, as the old hair smothers the new growth. Dirt and oil build up can have a similar effect, so its important to wash hair regularly. Stress can affect the circulation of nutrients and oxygen to the scalp, by causing the muscles in the scalp to tighten.

If this happens over a long period of time, premature hair loss can occur. This cause of hair loss is distinct from male pattern baldness (which is hormonal), but it can certainly exacerbate the condition. And stress reduction techniques are simple things that can be added to a daily routine, to prevent hair loss, and improve the overall quality of life.

References. NUTRAINGREDIENTS2; Wikipedia Health.