Hormones – how do they affect my hair.

What is a hormone? Hormones are defined as: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs. We all know the big ones, the sex hormones, estrogen and progesterone in women, testosterone in men. Women have some testosterone too, and levels fluctuate at certain times in our lives. These are responsible for the development of our adult bodies and mature reproductive organs. Our bodies experience fluctuations in these hormones at several key times in our lives; puberty, pregnancy, and menopause, and that subsequently has a huge effect on our hair health. Stress, and certain drugs, particularly oral contraceptive pills, have an effect on our hormones levels as well, that can ultimately lead to hair loss. 

Quick review- the life cycle of your hair:

Estrogens and progesterones protect against hair loss through expanding the growth phase and preventing shedding. 

Testosterone – the testosterone derivate DHT = dihyrotestosterone and its close other close relatives the androgens can shrink your hair follicles as well as shorten the resting phase of your scalp hair cycle, causing hair to grow out looking thinner and more brittle, as well as fall out faster. But, DHT can also make it take longer for your follicles to grow new hairs once old hairs fall out, depending on your individual sensitivity to its effects. This is where male pattern baldness comes from, depending on your genetics and sensitivity to DHT.

During pregnancy our bodies have an enhanced supply of estrogen and progesterone, amplifying the effect they have on our hair - lengthening the growth phase (catagen) and preventing shedding. That, along with elevated levels of other hormones, lead to that thick lustrous hair during pregnancy. But, look out! Within a few weeks to months after pregnancy, as the estrogen levels tumble back to normal, you hit the shedding phase running, and your hair comes out at an alarming rate. It will eventually level out, and things should get back to normal. 

During menopause, estrogen and progesterone levels drop, and we lose their protective effects. DHT levels rise. Again, DHT can cause your hair follicles to shrink as well as shorten the resting cycle, causing hair to grow out looking thinner and more brittle, as well as fall out faster. 

 If you take birth control pills, and then subsequently stop, you can get the same effect, a premature push into the resting  - telogen - phase, and lengthening of it (telogen effluvium – remember that?) and shortening of the growth phase, resulting in hair loss.  The good news is that it is usually only temporary. Taking certain kinds of birth control pills that have higher androgenic activity, can itself lead to hair loss as well.

Stress, as usual, is a huge culprit in hair loss through its effects on hormone levels. Cortisol, another kind of hormone, is overproduced during times of high stress, leading to an interruption in the brain signals that tell our bodies how much estrogen, progesterone and testosterone to produce, leading ultimately to hair loss.