There are several types of hair loss in women: genetic (aka female pattern baldness), hormonal (often associated with the menopause, or hormonal malfunctions such as hyperthyroidism) and alopecia areata, which is where clumps of hair simply fall out, almost overnight. There are other causes too: for example trychotillomania, which is a nervous disorder that causes the sufferer to pull out their own hair. It tends to affect young girls most, and is often considered to be a form of self-harm. Also, tension-related hair loss can result from overuse of hair extensions or over-processing.
Again, a mixture of factors. Some people simply have a genetic predisposition to hair loss which is triggered by age or lifestyle. Anecdotal evidence suggests that Asian and Southern Mediterranean women are especially prone to a general thinning of hair at the front and at the sides, although unlike men they rarely lose their hairline (in other words, it doesn’t recede, but just gets more sparse). There can be various triggers: stress, of course, but it can also affect people who go on severe diets, or who have eating disorders.
Some hair loss is very gradual: a thinning of the parting over a period of years; other types, such as alopecia areata, happen unexpectedly and almost overnight.
Women often experience hair loss following pregnancy and breastfeeding, as their levels of oestrogen and progesterone drop. This is almost always temporary, and stops once the levels have returned to normal. Extreme cases of dandruff, in which the sebum solidifies into a hard shell on the scalp, can also cause hair loss, although this is temporary. In children and babies it’s known as cradle cap. Chronic illness and chemotherapy also cause hair loss, although again this is reversible once full health has been restored.
Alopecia areata is patches of baldness that come and go at any age in a person's life, although it is most common in teenagers and young adults.
It is believed to be caused by a problem with the immune system, with genes making some people more susceptible than others. Although it can be an upsetting condition from which to suffer, hair usually grows back within a year for most people.
Scarring alopecia is hair loss which occurs as a result of other conditions. With this type of hair loss, the hair follicle is destroyed meaning the hair will not grow back. Wigs are available on the NHS and other options include hair transplants and scalp reductions.
The person who discovers a cure for hair loss will be a very rich man (or woman). Until then, it’s a case of trial and error. In the case of hereditary hair loss, which is known medically as androgenic alopecia, the most common form of treatment is minoxidil, either in a two per cent (for women) or five per cent (for men and severe cases in females) topical solution. You can buy this over the counter at Boots (which manufactures its own, perfectly effective, solution; the leading branded product is called Rogaine). This has a good success rate if used early enough. If treatment is started too late it is less successful, since over time the hair follicles weaken and eventually become inactive.
There are various supplements that claim to have an effect on thinning hair. Viviscal is a popular choice for men, and insofar as it works for male pattern baldness, it will also help treat the female variety. Other supplements aim to boost the endocrine stystem: Superior Hair, for example aims to boost female hormones (generally favourable to hair growth).
Find out more about hair loss on BBC Radio 4's Woman's Hour in which GTG's co-founder Sarah Vine shares her own hair loss story.