The main connection between progesterone and hair loss is that a lack of progesterone can cause an increase in male hormones in women and lead to pattern baldness. Another link between the two is that significant drops in progesterone occur in many women during and after menopause, and this is also the time when hair loss increases dramatically, although the two are not always directly related. Indirectly, low levels of progesterone can make the body more susceptible to other hair loss triggers, such as elevated testosterone levels and thyroid dysfunction.
Menopausal and postmenopausal women are at increased risk of hair loss, which is sometimes caused by a marked drop in progesterone. When this occurs, large amounts of certain steroid hormones normally produced by men in large quantities begin to be made. This is what can lead to a deeper voice and increased hair on the face or arms, while also causing symptoms such as male pattern baldness. This is much rarer for women than men, but it happens often enough for pharmaceutical companies to prepare specialized hair regrowth formulations tailored for women.
In this way, progesterone and hair loss are linked because low levels of female hormones are the cause of increased levels of male hormones. Sometimes taking a progesterone supplement in the form of injections, natural hormone suppositories, or capsules can help prevent further hair loss and promote hair growth. Other menopausal symptoms may also be relieved, depending on the type and dose.
Progesterone and hair loss are also indirectly linked because during the time most women experience a drop in progesterone, other issues can arise that lead to thinning hair. For example, one of the main causes of hair loss is thyroid dysfunction. The thyroid gland controls many bodily functions, so when it's not working properly, the side effects can be extreme. Sometimes thyroid problems can cause a drop in progesterone even in women of childbearing age, leading to the same problems mentioned above.
Thyroid problems are most often diagnosed in menopausal women, and can be exacerbated by already dramatic changes occurring in the body. This can also lead to hair loss, with or without being directly related to progesterone levels. Taking medications to improve thyroid gland function may help.
Another common link between progesterone and hair loss occurs in pregnant or postpartum women. During pregnancy, many women develop thicker hair that is healthier than it was before pregnancy. This is possibly caused by the higher levels of progesterone being produced. After childbirth, extra hair can begin to fall out quickly. In most cases, this is a temporary condition and does not lead to long-term bald spots or true pattern baldness.