Hair loss is a natural biological process, rooted in the hair renewal cycle. On average, a person loses between 50 and 100 hairs per day, a completely normal phenomenon that reflects the healthy activity of the hair follicles. However, when this loss becomes excessive, it can signal a temporary disorder or, in some cases, indicate the onset of alopecia. It is essential to distinguish abnormal hair loss, often triggered by factors such as stress or hormonal imbalances, from true alopecia, in order to adopt the appropriate corrective measures to prevent the situation from worsening.
Understanding the origin of hair loss
THE HAIR GROWTH CYCLE
To understand the phenomenon of hair loss, it is essential to understand the biological cycle that regulates hair growth. This cycle, divided into three distinct phases—anagen, catagen, and telogen—orchestrates the renewal of hair fibers and explains daily hair loss.
- Anagen phase : This phase, representing the period of active growth, extends over 2 to 7 years . It is characterized by an intense proliferation of keratinocytes ( the cells that produce keratin , a key protein for the structure and strength of hair) within the hair follicle, promoting the continuous production of new hair fibers.
- Catagen phase : A transitional phase of 2 to 3 weeks , where apoptosis (the process of programmed cell death, essential for cell regulation and renewal) of follicular cells causes regression of the follicle. Mitotic activity, cell division, ceases, and the hair is prepared for loss.
- Telogen phase : Resting phase, lasting 3 to 4 months , marked by the inactivity of the follicles. The hair is dormant until it is detached. The elimination of the hair allows the start of a new anagen cycle, ensuring hair renewal. It is therefore normal to lose around a hundred hairs daily, corresponding to the telogen hair that naturally detaches.
HEREDITARY ALOPECIA
Genetic predisposition plays a significant role in androgenetic alopecia, also known as hereditary pattern baldness . Research shows that certain genetic variations can increase the sensitivity of hair follicles to dihydrotestosterone (DHT) . DHT, a hormone derived from testosterone, binds to receptors in hair follicles, causing them to gradually shrink. Everyone produces DHT, but people who are genetically predisposed have follicles that are more sensitive to this hormone. This increased sensitivity causes the follicles to miniaturize, shortening the hair growth phase (anagen) and lengthening the resting phase (telogen) . As a result, hair becomes thinner, shorter, and eventually stops growing, leading to gradual and permanent hair loss.
HORMONES OFTEN RESPONSIBLE FOR HAIR LOSS
HORMONAL IMBALANCES
Hormones play a crucial role in hair health. Besides DHT being involved in androgenetic alopecia, other hormonal imbalances can also affect hair growth. For example, thyroid disorders, such as:
- Hypothyroidism and Hyperthyroidism : These conditions can cause diffuse hair loss by disrupting the normal growth cycle of hair follicles.
- Polycystic ovarian syndrome (PCOS) : Can cause excess androgen production, contributing to hair thinning and loss.
- High cortisol levels : The stress hormone can disrupt the hair growth cycle, causing premature entry into the telogen phase and diffuse hair loss.
POST PARTUM HAIR LOSS
After pregnancy, many women experience significant hair loss due to hormonal fluctuations. During pregnancy, high estrogen levels prolong the hair growth phase (anagen), but after delivery, the rapid drop in hormone levels causes hair to sync into the resting phase (telogen), causing noticeable hair loss. This condition often occurs between two and four months after delivery. Although temporary, it can be stressful for new mothers.
ENVIRONMENTAL FACTORS AND LIFESTYLE
STRESS EXACERBATES HAIR LOSS
Chronic stress is a major contributor to hair loss. It can disrupt the hair growth cycle, causing hair to enter the telogen phase prematurely. Normally, about 10% of hair follicles are in the telogen phase at any given time, but under stress, this percentage can increase dramatically, causing a diffuse hair loss called telogen effluvium. This condition often occurs after a major stressful event, where a large amount of hair falls out at once.
THE CONSEQUENCES OF AN UNBALANCED DIET
An unbalanced diet, lacking in essential nutrients such as iron, zinc, B vitamins and protein, can lead to hair loss. Hair, being a non-vital part of the body, is often the first to suffer from nutritional deficiencies. For example:
- Iron deficiency : Can lead to anemia, limiting the blood's ability to carry oxygen to the hair follicles and thus affecting hair growth.
- Zinc deficiency : May disrupt the synthesis of proteins needed for hair formation.
- Lack of B vitamins : Can impair the metabolism of hair follicles, weakening the hair structure.
POLLUTION AND EXTERNAL FACTORS
Environmental pollutants, such as fine particles, heavy metals and toxins, can damage the scalp and hair follicles, contributing to hair loss. UV rays, in particular, can weaken the hair structure by damaging the cuticle, the hair’s protective layer, and penetrating the hair fiber to break down essential proteins like keratin.
UNBALANCED SCALP AND CLOGGED FOLLICLES
An unbalanced scalp, clogged with excess sebum, dead cells and hair product residue, can prevent hair follicles from functioning properly. This obstruction can lead to local inflammation and disrupt the hair growth cycle. Regular and thorough scalp cleansing is essential to maintain a healthy environment for hair follicles, promote hair growth and prevent hair loss.
PATHOLOGICAL AND DRUG-INDUCED ALOPECIA
MEDICAL CONDITIONS
Certain medical conditions can cause hair loss, significantly affecting hair health. Here are some examples:
- Lupus : An autoimmune disease that causes inflammation and damage to hair follicles, leading to diffuse or localized hair loss.
- Hypothyroidism : Underactive thyroid gland slows down metabolism, affecting hair growth and leading to hair thinning.
- Alopecia areata : Autoimmune disease that specifically attacks hair follicles, causing hair loss in patches.
HAIR LOSS AS A SIDE EFFECT OF SOME MEDICATIONS
Many medications can cause hair loss as a side effect. Here are some examples:
- Chemotherapy : Cancer treatments target fast-growing cells, including those in hair follicles, causing rapid and significant hair loss.
- Arthritis Medications : Some anti-inflammatory medications can disrupt the hair growth cycle.
- Antidepressants : Some treatments for depression can cause diffuse hair loss.
- Heart disease medications : Beta-blockers and other heart medications can also affect hair growth.
SOLUTIONS AND PREVENTION
To correctly diagnose the cause of alopecia and receive appropriate treatment, it is essential to consult a dermatologist or trichologist.
Using specialized hair care products can help prevent hair loss and improve hair density. Fauve Densifying Serum is formulated with targeted natural active ingredients to effectively combat hair loss:
- Turmeric : Activates the regeneration of hair follicles.
- Pea shoot extract : Stimulates hair stem cells and limits hair loss.
- Caffeine : Improves blood circulation and promotes hair growth.
- Niacinamide : Strengthens the scalp's skin barrier and protects against external damage.