Androgens & Hair
Androgens are not only hormones that are very important for men. They also play an important role in women's bodies.
Testosterone belongs to the group of androgens and is the best-known member of this group. Androgens are essential for the development and differentiation of our secondary sexual characteristics and organs in both the male and female body, as well as for reproduction.
Sebaceous glands and some of our hair follicles are androgen-dependent. In this blog post, we will first focus on hair & androgens.
Hair Types
There are three different types of hair: lanugo, vellus, and terminal hair. In terms of androgens, the latter two types are particularly important.
Lanugo hair plays a role at birth and is short, soft, and unpigmented.
Vellus hair: fine, lightly pigmented hair that can be found all over the body and is less noticeable. This is also called woolly or downy hair.
Terminal hair: more visible hair that is more pigmented, coarser, and thicker. How pronounced the hair growth is depends on genetic and also hormonal factors. But diseases or medications can also affect terminal hair.
How an individual's hair growth looks is determined by genetics and hormones.
However, it is clear that over the course of our lives, some of the vellus hairs develop into terminal hairs and vice versa. Especially during puberty, a large part of the finer hairs transforms into thicker terminal hairs. In men, this is about 90%, and in women, up to 35%.
Regarding head hair, the exact opposite can happen. The thicker hairs can develop into finer vellus hairs or even disappear completely. This is then referred to as hereditary hair loss or androgenetic alopecia.
Which hairs are androgen-dependent and which are not?
There are three groups here: non-androgen-dependent, dependent on low androgen concentrations, and androgen-dependent.
- Non-androgen-dependent hair:
Eyebrows, eyelashes, the hair on the forearms and lower legs, and the lower parts of the scalp hair. By the way, all of these are terminal hairs that create the impression of hair growth.
- Hair that is only dependent on relatively low androgen concentrations:
underarm hair, lower pubic hair, and part of the head hair (temporal and crown areas, i.e., virtually the middle part of the hairy head). Interestingly, pubic and underarm hair transforms from finer vellus hairs into thicker terminal hairs due to the influence of androgens. Whereas this thicker hair type, which also occurs in the area of the hairline, is transformed into the thinner vellus hair type in puberty under the influence of androgens.
So pubic and underarm hair develop from thin to thick hair, and on the head exactly the opposite. That's how we would like to have it... Or not ?!
- Finally, there are androgen-dependent hairs:
these depend on higher androgen concentrations. This means that this type of hair physiologically occurs in men and in women only if there is a disorder in the androgen balance. Typical for this are beard growth, hair growth on the ears and nostrils, hair on the back, between and above the breasts, and from the pubic bone up to the navel. By the way, due to the higher androgen concentrations, fine thinner hairs become thicker, darker hairs, i.e., from vellus hair to terminal hair.
Interestingly, here again an opposite effect occurs when looking at the hair on the head. In the temporal and crown areas (the middle part of the hairy head), higher androgen concentrations turn thicker terminal hairs into thinner vellus hairs.
The cause of hair loss in women* is therefore not infrequently an androgen excess.
As already described, men are more affected by androgen-dependent hair growth because they have higher amounts of male hormones. But women can also develop hair in unwanted places as a result of excessively high androgen concentrations.
Often, a genetically determined hypersensitivity of the hair follicles to androgens or the falling estrogen levels during menopause or after pregnancy is the reason for increased hair growth/loss. Underlying diseases such as PCOS can also result in hair problems.
Another reason can be stopping the pill, which can lead to increased testosterone concentrations. This effect is called the "androgen rebound effect", which we discuss in more detail in our article on hair loss and pimples after stopping the pill.
Androgens as a cause of hair loss in women - what to do?
Even if increased hair growth or hair loss is merely an external issue, the distress of those affected is often very high. Permanent hair removal can be painful and expensive.
Regarding testosterone concentrations, however, it is possible to pay attention to a few things.
