We’re all familiar with male pattern baldness and what it looks like, but how many of us understand what causes it and how it’s connected to male hormones? And what about female pattern baldness, and how things like menopause or the pill can affect the hair? Here is a simple explainer on the relationship between sex hormones and your hair. 

Male and Female Sex Hormones

The first thing you need to know is that both men and women produce both male and female hormones, but in different amounts. Male hormones are called androgens and female hormones are called estrogens. Not surprisingly, men produce higher amounts of androgens, such as testosterone. It is the balance of these hormones that has a major effect on the hair.

Source of Sex Hormones

The sex glands – the ovaries in women and testes in men – are the main source of sex hormones, but weak androgens are also produced by the adrenal cortex (which sits atop each kidney). These weak androgens can be converted to more potent androgens in the skin.

Hormones and The Hair

In general, estrogens are good for scalp hair whereas androgens are bad. In genetic hair loss in men and women, the potent androgen testosterone is converted to dihydrotestosterone (DHT), which acts on hair follicles and triggers genetically predisposed hairs to become finer and smaller with each hair cycle.

The reason that only hairs on the top and front of the scalp are affected by DHT is because the hair follicles in these areas have receptors for androgens, whereas the hair follicles at the back and sides of your scalp do not have such receptors and so are not influenced by DHT.

Strangely, facial hair increases in response to DHT, so women who exhibit genetic hair thinning may have an increase in facial hair, a condition known as hirsutism. Surprisingly, most women and men who show genetic hair loss usually have quite normal levels of androgens and estrogens; the issue is actually around the hair follicles’ sensitivity to DHT, with those with genetic hair thinning being particularly sensitive to it. This sensitivity is determined by the genes we inherit from our parents – hence why this type of hair loss is known as genetic hair thinning.

Sex Hormones, Inflammation and Oxidative Stress

There are two other factors that can contribute to genetic hair loss: inflammation and oxidative stress.

Most people exhibiting genetic hair thinning also have inflammation around the hair follicles as a result of white blood cells attacking the stem cells of the hair follicles. Furthermore, androgens increase oxidative stress (free radicals attacking the hair), which leads to inflammation and scarring of hair follicles. Antioxidants are therefore important to combat oxidative damage and inflammation. Eating lots of fruit and vegetables and taking antioxidant supplements such as vitamin D can benefit the hair.

Sex Hormones, Life Stages and Hair Loss

In men, genetic hair loss often begins in the teens in response to the increase in androgens at puberty. With women, genetic hair loss is triggered or worsens at the time of menopause when estrogen levels drop, which increases the relative influence of androgens on the hair. Having said that, I do see a lot of younger women exhibiting genetic hair thinning. Some oral contraceptives can be responsible for this because progestins such as norethisterone (norethindrone) and levonorgestrel in oral contraceptives can have an androgenic effect on the hair.

Women undergoing therapy for breast or ovarian cancer sometimes take medication to reduce the production and effect of estrogens. One possible side effect of these medications is to trigger or worsen genetic hair thinning in those women genetically predisposed, because of the resultant increase in the influence of androgens on the hair. Steps can be taken to reduce this androgenic effect, including taking antioxidants.

Sex Hormones and Sebum

Sex hormones not only have a big influence on the hair but also influence the production of sebum (oil) onto the skin’s surface; androgens increase oiliness, while estrogens decrease it. That is why some young women with acne take specific oral contraceptives, to reduce oiliness and alleviate the acne. If your scalp does get oily quickly, daily shampooing is recommended to prevent the sebum from accumulating on the scalp and causing itching and scaliness.

Occasionally, females produce excessive levels of androgens, which can give rise to oily skin, hirsutism, genetic hair thinning, disturbed menstrual cycles and increased body weight. Your doctor can run blood tests to determine if there is a problem with your sex hormone levels.

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