Hair thinning, also known as female pattern hair loss (FPHL) or androgenic alopecia in women, is a common condition that many women experience. The underlying biology and physiology of hair thinning in women are multifaceted, involving genetics, hormones, aging, and other factors.

 

Hormonal Influence:

 

Androgens: These are male hormones present in both men and women. Dihydrotestosterone (DHT) is a potent form of testosterone that affects hair follicles. When androgen receptors on hair follicles are activated by DHT, the growth phase (anagen) of the hair cycle shortens, and the hair follicle miniaturizes, leading to finer, shorter hairs.

 

Estrogen: Estrogen has a protective effect on hair. During life events where estrogen levels decline, such as menopause, there's a relative increase in the influence of androgens on hair follicles, potentially leading to thinning.

 

Ovarian Cysts: Polycystic ovary syndrome (PCOS) is a condition in which cysts form on the ovaries, leading to an overproduction of androgens, which can result in hair thinning.

 

Genetic Predisposition:

FPHL has a hereditary component. If female relatives on either side of a woman's family have experienced hair thinning, she may be more susceptible to it.

 

Aging: As women age, hair density decreases, and the rate of hair growth slows. This is a natural process, but when combined with hormonal changes, especially around menopause, it can lead to noticeable hair thinning.

 

Hair Follicle Miniaturization: Over time, affected hair follicles become smaller in size (miniaturize). As a result, the hair they produce becomes thinner, shorter, and less pigmented. Over several hair cycles, these miniaturized follicles eventually produce vellus hairs (very fine, short hairs) instead of terminal hairs (longer, coarser hairs).

 

Other Contributing Factors:

 

Nutritional deficiencies: Deficiencies in iron, vitamin D, biotin, and protein can influence hair health.

 

Thyroid abnormalities: Both hyperthyroidism and hypothyroidism can lead to hair thinning.

Stress: Physical or emotional stress can trigger hair thinning.

Medications: Some medications, including certain antidepressants, antihypertensives, and oral contraceptives, can lead to hair thinning as a side effect.

Traction Alopecia: Constant tension or pulling on hair (e.g., tight hairstyles) can cause hair loss.

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Other medical conditions: Diseases such as lupus and dermatological conditions like seborrheic dermatitis can contribute to hair thinning.

 

Hair Growth Cycle Changes:

 

The life cycle of hair consists of the anagen, catagen, and telogen phases. Thinning hair is often the result of a disruption in this cycle. In FPHL, more hairs transition from the anagen (growth) phase to the telogen (resting) phase, leading to increased hair shedding (telogen effluvium). It's worth noting that while hair thinning in women often has a pattern (starting with widening of the centre hair part), it's typically less pronounced than male pattern baldness. However, the psychological impact can be significant, affecting self-esteem and confidence.

 

Diagnosis and treatment often involve addressing underlying causes, hormonal therapies, topical treatments like minoxidil, and in some cases, hair transplant procedures. If someone suspects they're experiencing hair thinning, consultation with a dermatologist or trichologist is recommended.