Testosterone and hair loss: the role of hormones

Testosterone, a predominantly male hormone, plays a central role in hair growth and loss. For some, its conversion to dihydrotestosterone (DHT) can influence the miniaturisation of hair follicles, leading to androgenic alopecia, a common form of baldness. Find out what links exist between testosterone and hair loss?

What is Dihydrotestosterone (DHT)?

Dihydrotestosterone (DHT) is an androgenic hormone derived from testosterone. It plays a key role in the development of certain male characteristics and is involved in a number of physiological and pathological processes in the body.

DHT is formed from testosterone through the action of an enzyme called 5-alpha reductase. There are several types of this enzyme, but it is mainly types 1 and 2 that are responsible for converting testosterone into DHT.

During foetal development, DHT plays a crucial role in the formation of the male genitalia. At puberty, it contributes to the development of secondary male sexual characteristics, such as beard growth, voice changes and body hair growth.

DHT is not only present in men; it also exists in women, albeit in smaller quantities. As in men, DHT in women is produced by the conversion of testosterone by the enzyme 5-alpha reductase. Although women generally have much lower levels of testosterone than men, this hormone is still present and can be converted into DHT.

How does testosterone affect hair?

Testosterone plays a key role in hair health and growth, particularly with regard to baldness, also known as androgenic alopecia.

In genetically predisposed males, hair follicles, particularly those in the hairline and at the top of the scalp, are more sensitive to DHT.

DHT binds to receptors in sensitive hair follicles, causing them to miniaturise. This gradually reduces the hair growth phase (anagen phase). Over time, hair becomes thinner, shorter and eventually stops growing.

Although DHT is a major culprit of male pattern baldness it's not the only cause. Other factors, such as genetics, stress, hormonal imbalances, illness, medication and nutrition, can also influence hair health.

Testosterone and androgenetic alopecia in women

As in men, genetic sensitivity to the effects of DHT can lead to androgenic alopecia in women. However, DHT-related hair loss in women often manifests itself differently than in men, usually taking the form of diffuse thinning rather than receding hairline or baldness at the crown of the head.

Good to know: there may be a link between androgenetic alopecia in women and polycystic ovary syndrome (PCOS). This common hormonal disorder in women can lead to increased production of androgens, including testosterone, which can then be converted into DHT. Women with PCOS may experience symptoms such as hair loss, hirsutism (excessive hair growth on the face and body) and acne, all associated with high levels of androgens.

How does androgenetic alopecia manifest itself in men?

One of the first signs is often the recession of the temporal gulfs, giving the hairline an "M" shape. After, or sometimes simultaneously with, temple recession, there may be thinning or hair loss at the top of the skull (vertex). This can gradually spread, forming a circular bald patch. Over time, these bald areas may spread, eventually joining together. In the most advanced cases, only a band of hair remains on the sides and back of the head.

The progression and severity of androgenetic alopecia can vary considerably from one individual to another. While some men may experience only mild recession of the temples throughout their lives, others may experience significant hair loss in early adulthood.

What are the treatments for androgenetic alopecia?

There are many treatments available to combat androgenetic alopecia, whether it occurs in men or women. Some focus on stimulating hair growth, while others focus on reducing the effects of DHT.

Drug treatments

A number of treatments are available to combat advanced androgenetic alopecia. They target either the revitalisation of hair follicles or the neutralisation of dihydrotestosterone and other associated sex hormones.

  • Minoxidil is available in liquid or mousse form. This topical treatment can be used by both men and women. It stimulates hair growth and slows down hair loss.
  • Finasteride: prescribed mainly for men, this oral medication inhibits the enzyme that converts testosterone into DHT. It has been shown to slow down hair loss and, in some cases, cause hair to grow back.

Hair transplants

Hair transplantation is a surgical procedure commonly used to treat androgenetic alopecia in both men and women. The procedure aims to restore hair density by removing hair follicles from a donor area (usually the back or side of the scalp where hair is more resistant to DHT) and implanting them in the balding area.

Hair transplants are considered safe when carried out by an experienced surgeon. However, as with any surgical procedure, there are risks and potential side effects. A pre-operative consultation with a specialist hair transplant surgeon is essential to determine your eligibility and discuss expectations and potential outcomes.

Serums and solutions

Serums and solutions are designed to target hair loss problems at source, by acting directly on the hair follicles. To be effective, these products must penetrate the epidermis to reach and treat the hair follicles.

As with medication, results vary from person to person. Some people may see a significant improvement, while others may see only slight changes.

That's why it's vital to stress the importance of accurate diagnosis.

An appropriate diagnosis helps to identify the underlying cause of hair loss. In some cases, the loss may be due to genetic factors, while in others it may be the result of hormonal imbalances, stress, illness or medication. Understanding the exact cause is essential for choosing the most appropriate treatment and for setting realistic expectations regarding results.

Furthermore, by obtaining a professional diagnosis, you can also ensure that you avoid unnecessary or potentially harmful treatments. For example, the use of products designed to block DHT may not be beneficial if hair loss is not due to sensitivity to this hormone.

Centre Clauderer specialises in the treatment and diagnosing hair problems, in Paris or remotely. Once the diagnosis is complete, the specialist will discuss the results with you and provide you with treatment recommendations tailored to your situation.

Jean-François Cabos

Jean-François Cabos is the creator of a unique hair care method based on the research he coordinated, which led to the publication of the book "Cheveux, Racines de Vie" with Hélène Clauderer by Robert Laffont (Collection "Réponses/ Santé").

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