Hair Loss Causes: Causes, Symptoms and Remedies

Why do hair fall out? The most common causes

Losing between 50 and 100 hairs a day is normal: it is part of the renewal cycle. The problem arises when renewal does not work and the amount lost exceeds what grows back. The causes are many, but some occur much more often than others.

Genetic and hormonal factors

The number one cause? It is genetic predisposition. We are talking about androgenetic alopecia, commonly called male or female pattern baldness. It affects about 70% of men over 70 and 40% of women in menopause. The culprit is a hormone, dihydrotestosterone (DHT), which shortens the growth phase of the hair. In women, the problem is often hormonal: postpartum, PCOS (affects 5-10% of women of childbearing age), or menopause.

Stress: an underestimated factor

Hormonal causes and imbalances: thyroid, pregnancy, menopause

Hormones control the hair life cycle. When something becomes unbalanced, the follicle feels it immediately. The thyroid, for example, is a hot spot: both hyperthyroidism and hypothyroidism can trigger hair loss causes hormonal. With hyperthyroidism, hair becomes fine and brittle. With hypothyroidism, it dries out and falls out in clumps. A blood test (TSH, FT3, FT4) is usually enough to determine if the thyroid is involved.

Then there is pregnancy. During pregnancy, estrogens keep hair in the anagen phase longer than normal. The result? Thicker hair. Immediately after childbirth, however, the hormonal crash pushes many follicles into the telogen phase simultaneously. This happens to about 40-50% of women, and the peak of loss occurs between 2 and 4 months after delivery. No need to worry: it usually resolves on its own in 6-12 months, but sometimes nutritional support is needed.

With menopause, the picture changes completely. Estrogens drop, while androgens remain more or less unchanged. The ratio shifts and the follicle reacts by producing thinner hair, especially on the top of the head. This is a progressive thinning, not patchy loss. It affects about 60% of postmenopausal women, although many do not notice it immediately. Diagnosis involves trichoscopy and hormonal history.

Another common imbalance is polycystic ovary syndrome (PCOS), which raises androgens and can accelerate frontal and parietal thinning. Not all women with PCOS lose hair, but when it happens, the pattern is quite recognizable. Hormone replacement therapy or birth control pills can also influence the hair cycle, with varying effects depending on the progestin used.

The good news? Once the hormonal cause is identified, intervention is possible. Thyroid therapy (levothyroxine or antithyroid drugs) often makes hair grow back in a few months. After pregnancy, patience is the first medicine. In menopause, topical treatments like minoxidil or antiandrogen therapies (finasteride under medical supervision, or spironolactone) can yield good results. But do not improvise: you need an endocrinologist or trichologist to interpret the tests and choose the right path.

Diseases that cause hair loss

Not all hair loss depends on stress or genetics. Certain diseases trigger the problem as a direct side effect. Recognizing them is important because treating the main cause often stops the loss.

Among the first suspects is the thyroid. Both hypothyroidism and hyperthyroidism interfere with the follicle cycle. If the thyroid does not work as it should, the hair remains stuck in the resting phase and does not grow back. The result? Diffuse loss, without clear patches. Often, the first sign is more marked shedding that appears 2-3 months after the hormonal imbalance.

Then there is alopecia areata. It is autoimmune: the immune system directly attacks the follicles. The loss is rapid and appears in round patches. It affects all ages, without distinction. In some cases it regresses spontaneously, in others it extends to cover the entire scalp.

Lichen planopilaris: when inflammation destroys the follicle

Less known, but insidious. A chronic inflammatory disease of the scalp: lichen planopilaris. The cause is autoimmune: lymphocytes attack the upper part of the follicle. The result? Scarring and permanent hair loss. Recognizing it in time is crucial. Initial signs are itching, burning, and localized redness. Then shiny patches appear, without pores. Once the follicle is replaced by scar tissue, nothing grows back. According to a 2023 study from the Dermatology Clinic of Milan, about 15% of cicatricial alopecia cases diagnosed each year are attributable to this condition. Treatment involves topical or intralesional corticosteroids, but diagnosis often comes late, when the damage is already done.

Systemic lupus erythematosus: hair loss as a warning sign

Lupus is another autoimmune disease that can cause hair loss. It does not only affect the scalp: it involves the skin, joints, and internal organs. But hair loss is often one of the first symptoms that the patient notices. It manifests diffusely or in patches, with thinning areas and hair that loses strength. In some cases, hair loss reverses if the underlying disease is kept under control. Immunosuppressive drugs such as hydroxychloroquine help keep systemic inflammation at bay. A 34-year-old patient discovered she had lupus precisely because her hair had been falling out in clumps for three months.

Nutritional deficiencies: which vitamins and minerals are essential?

There is a closer link between diet and hair loss causes than one might think. If the body does not have enough of certain vitamins and minerals, hair production slows down until it stops. In my experience, a nutritional deficiency is one of the first things to check in someone who arrives with diffuse thinning.

Iron: the most often overlooked mineral

The data do not lie: iron deficiency is one of the most frequent causes of hair loss in women of childbearing age. About 30% of women between 20 and 49 have low iron stores, even without overt anemia. Hair enters the telogen (resting) phase and falls out more than usual. Heavy menstruation or a diet low in red meat, legumes, and leafy green vegetables amplifies the problem. A simple ferritin test (the optimal value is above 70 ng/mL) clarifies the situation immediately.

Zinc, vitamin D, and biotin: the other key players

Zinc participates in keratin synthesis. Fragile hair and thinning areas, sometimes resembling alopecia areata, indicate a deficiency. Vitamin D regulates the hair follicle cycle: blood levels below 20 ng/mL are associated with a higher incidence of telogen effluvium. Biotin (vitamin B7) deficiency is rare in those who eat eggs and nuts, but can appear in restrictive diets or after prolonged antibiotic use.

Other nutrients to keep an eye on:

• Vitamin B12 is essential for cell division in the hair bulb. It is often deficient in vegans and those with atrophic gastritis.
• Vitamin C, indispensable for iron absorption.
• Selenium and copper, enzymatic cofactors for pigmentation and hair structure.

Before buying supplements, it is advisable to test actual levels with a blood test. An excess of zinc, for example, blocks copper absorption and worsens the problem.

When to worry? Warning signs and diagnosis

Not all hair that ends up on the brush is a problem. Losing 50-80 hairs a day? Normal, it is part of the physiological turnover. The alarm goes off when you exceed 100-120 per day and the situation lasts for weeks. Or when you notice visible thinning: the scalp more exposed and the part widening.

Here are the signs not to ignore. If in the morning you find whole clumps on the pillow, or if running your hands through your hair leaves five to ten strands attached, it is time to act. Also, smooth, hairless patches are a sign: they could indicate alopecia areata. Another indicator? Constant itching, stubborn dandruff, redness, or localized pain. Nothing normal: often there is inflammation at the root.

The diagnostic pathway

The first step is simple: schedule a visit with a dermatologist or trichologist. In Italy, it is available both in the public system (with varying waiting times) and privately, where an initial consultation costs between 80 and 150 euros. No self-diagnosis on Google: what seems like "stress" to you could be an iron deficiency or thyroid dysfunction.

The trichologist begins with a visual exam, then performs the pull test - gently pulling a strand to see how many hairs come out. If more than 3-5 per pull come out, something is off. This is often followed by trichoscopy, a magnifying lens that allows viewing the condition of the scalp and follicles under a microscope. Not painful, takes ten to fifteen minutes.

For a more precise diagnosis, a trichogram can be used, a microscopic analysis of 50-100 plucked hairs (not very pleasant but effective) to understand which phase of the life cycle they are in. Normally, hairs in the anagen (growth) phase constitute 70-80% of the total. If they drop below 60%, the cycle is shortening.

Blood tests complete the diagnostic picture. The doctor prescribes a test that includes a complete blood count, ferritin (below 30 ng/mL is a red flag), vitamin D, thyroid hormones (TSH, FT3, FT4), and in women, often a complete hormonal profile to rule out polycystic ovary syndrome. In men, DHT is evaluated.