Androgenetic Alopecia: What It Is and How It Manifests

Receding temples or a thinning crown are not a sentence and not "bad genetics you can't do anything about." Androgenetic alopecia is the most common type of hair loss in men and a significant share of cases in women, and it has a specific mechanism. Below is what is known about it, without marketing promises.

What androgenetic alopecia is

Androgenetic alopecia is a thinning of the hair that in men leads to baldness of the parietal and frontal areas, and in women to thinning along the central part line extending to the lateral surfaces of the head. This is not about hair falling out more often than usual: a daily loss of 50–100 hairs is normal, and in most people they grow back. In androgenetic alopecia, the follicle gradually shrinks, the hair becomes thin, short, and colorless, vellus, and no longer covers the skin.

This is a permanent type of baldness; temporary hair loss is caused by illness, stress, cancer treatment, weight loss, or iron deficiency. Severity in men is assessed using the Norwood scale, and in women using the Ludwig scale.

Causes of male baldness

Over 95% of all cases of baldness in men are androgenetic alopecia. It is associated with androgens, masculinizing steroid hormones produced by the bodies of both sexes, and with heredity: this type of hair loss usually runs in families.

The mechanism has been studied at the cellular level. Androgens act through dermal papilla cells: they bind to the receptor and alter the production of paracrine factors on which hair stem cell division depends. When the signal goes awry, the follicle is not reproduced at its former size. Dihydrotestosterone is formed from testosterone by the enzyme 5α-reductase, and aromatase competes with it for the same testosterone: the more aromatase in the cell, the less substrate is available to 5α-reductase. Follicles on the back of the head have more aromatase than those on top of the head — 3 times more in men and 1.8 times more in women.

How baldness manifests in men: receding hairline and crown

Male-pattern baldness affects the parietal and frontal areas. The hairline recedes, the area of thinning widens, and the skin between the hairs becomes noticeable. Hair does not disappear instantly: it miniaturizes, becoming shorter and lighter until it stops covering the skin.

The rate varies from person to person, but the process has a cutoff point: 10–12 years after the onset of alopecia, the follicular openings become overgrown with connective tissue, and they can no longer produce even vellus hairs.

Androgenetic alopecia in women

In women, androgenetic alopecia looks different: the central part area thins, extending to the lateral surfaces of the head. The reported frequency varies widely — from 20% to 90% of all cases of hair loss — and the spread is explained by the fact that the manifestations are less noticeable and less well diagnosed.

The hormonal background works in both directions. Estradiol prolongs the hair growth phase — during pregnancy there are more growing hairs, and after childbirth estrogen levels fall, and hairs that were retained in the growth phase fall out almost synchronously, causing temporary thinning.

How androgenetic alopecia is diagnosed

A doctor can determine the cause of hair loss by examining the hair, and severity is assessed using the Norwood and Ludwig scales.

The logic is this: first figure out the cause with a doctor, and only then think about commercial hair restoration clinics. If hair loss affects your well-being, this should be mentioned at the appointment — care includes psychological counseling and support groups.

• Hair examination by a doctor
• Assessment using the Norwood scale in men
• Assessment using the Ludwig scale in women
• Discussion of the impact of hair loss on well-being

When to see a doctor

The reason for a visit is concern about hair loss. Temporary hair loss occurs with illness, stress, weight loss, iron deficiency, and cancer treatment.

Androgenetic alopecia by itself is not a reason to call an ambulance; 103/112 — for life-threatening conditions: signs of stroke, heart attack, severe injuries.

This material is for reference: it helps you come to an appointment with the right questions, but does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer