When we ask why hair falls out in the first place, it’s important to understand the various underlying triggers. Identifying the cause is essential, as different types of hair loss require different treatment approaches.
Hereditary Hair Loss (Androgenetic Alopecia)
Androgenetic alopecia is the most common form of hair loss. Around 80 percent of men worldwide are affected to varying degrees, while among older women the prevalence is about 57 percent.
The mechanism behind it is fascinating: in the body, the male sex hormone testosterone is converted by an enzyme called 5-alpha-reductase into its active form, dihydrotestosterone (DHT). In individuals with a genetic predisposition, the hair follicles are particularly sensitive to DHT, which leads to the following effects:
- The growth phase of the hair becomes shorter
- The hair does not grow as long
- The hair becomes thinner and falls out more easily
Interestingly, the predisposition to androgenetic alopecia can be inherited from either parent. However, the likelihood and extent of hereditary hair loss cannot be precisely predicted, as multiple genes are involved.
The visible pattern of hair loss differs significantly between men and women. In men, it often begins with receding hairlines and can eventually result in a bald crown. In women, the thinning typically appears along the parting line, while the frontal hairline generally remains intact.
Hormonal Changes in Women
Hormonal fluctuations play a particularly important role in hair loss among women. Hormones directly affect the hair growth cycle and the cell division activity of the hair follicles.
While estrogens stimulate hair growth, a drop in estrogen levels or a rise in male hormones can lead to hair loss. Women are especially susceptible during the following life stages:
- During puberty
- After pregnancy
- During menopause
During menopause, estrogen levels decrease while androgen (male hormone) activity becomes more dominant. This explains why many women with a genetic predisposition only experience hormonal hair loss around menopause.
Additionally, suddenly stopping birth control pills after long-term use can trigger hormonal changes that also cause hair shedding. A particularly concerning condition is polycystic ovary syndrome (PCOS), which affects up to one in ten women and is the most common hormonal disorder among women of childbearing age.
Stress, Diet, and Medications as Triggers
Hair loss can also be caused by factors beyond genes and hormones — stress being one of the most significant. Doctors are increasingly observing cases of diffuse hair loss associated with chronic or acute stress.
The mechanism is complex: under stress, the body releases more of the stress hormone cortisol, which inhibits hair growth. At the same time, the number of nerve fibers surrounding each hair follicle increases. These nerve fibers release chemical messengers that can irritate immune cells and trigger neurogenic inflammation.
The good news is that once the stress subsides, hair often grows back — in many cases even stronger and more pigmented than before.
Other contributing factors to diffuse hair loss include:
- Nutrient deficiencies, particularly iron deficiency
- Side effects of certain medications
- Various systemic diseases
Among the most common causes of diffuse hair loss are nutritional deficiencies. Therefore, a healthy and balanced diet is essential for anyone seeking strong, vibrant hair.
Before turning to any hair loss remedies, it’s crucial to identify the underlying cause — only then can an effective and targeted treatment be chosen.