Why Is Your Hair Falling Out?

Hair loss affects millions worldwide, causing both physical and emotional distress. Whether you notice thinning patches, receding hairlines, or clumps in your shower drain, understanding the root causes is the first step toward addressing the issue. Let's examine the most common culprits behind hair loss and what they mean for your health.

Genetic Factors: The Hair Loss Lottery

Your DNA plays a significant role in determining your hair's destiny. Genetic causes of hair loss account for the majority of cases, particularly androgenetic alopecia, commonly known as male or female pattern baldness.

For men, this typically manifests as a receding hairline and thinning at the crown, eventually progressing to partial or complete baldness. The most common causes of hair loss in men involve sensitivity to dihydrotestosterone (DHT), a hormone derived from testosterone. When hair follicles are genetically programmed to be sensitive to DHT, they gradually shrink over time, producing thinner, shorter hairs until they stop producing hair altogether.

Women experience genetic hair loss differently. The most common causes of hair loss in women of genetic origin typically present as overall thinning across the scalp, particularly noticeable with a widening part line. While women produce less testosterone than men, hormonal changes can trigger genetic predispositions to hair loss, especially after menopause when estrogen levels decrease.

Genetic hair loss tends to follow predictable patterns based on family history. If you have close relatives who experienced early or significant hair loss, your chances increase substantially. However, these genes can be inherited from either parent, not just the maternal side as commonly believed.

Hormonal Imbalances and Their Impact

Hormonal causes of hair loss extend beyond genetic predispositions and affect both men and women throughout different life stages. These fluctuations can disrupt the normal hair growth cycle, leading to excessive shedding or thinning.

For women, pregnancy and childbirth create dramatic hormonal shifts. Postpartum hair loss causes concern for many new mothers who notice increased shedding about three to six months after delivery. During pregnancy, elevated estrogen levels prolong the growth phase of hair, resulting in fuller, thicker hair. After childbirth, hormone levels drop rapidly, causing many hair follicles to enter the resting phase simultaneously, leading to noticeable shedding. While alarming, this type of hair loss is typically temporary.

Thyroid issues and hair loss are closely connected. Both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid) can disrupt the hair growth cycle. Thyroid hormones regulate metabolism throughout the body, including the rate at which hair follicles replace themselves. When thyroid function is compromised, hair may not be replaced at the normal rate, resulting in thinning across the scalp.

Polycystic ovary syndrome (PCOS) represents another hormonal condition affecting women that can cause hair loss on the scalp while paradoxically increasing hair growth on the face and body due to elevated androgen levels. Other endocrine disorders and hormonal therapies, including some birth control methods, can also trigger or exacerbate hair loss patterns.

Stress and Lifestyle Factors

Modern life's demands can literally cause your hair to fall out. Hair loss due to stress occurs through several distinct mechanisms, each highlighting the close connection between your mental state and physical health.

Telogen effluvium is a form of temporary hair loss that occurs after physical or emotional stress pushes a large number of hair follicles into a resting phase. Instead of the normal 10% of hairs being in the resting phase, stress can increase this percentage dramatically. Several months later, these resting hairs fall out when new hairs begin to grow. Significant stressors that can trigger this condition include:

Major surgery or severe illness
Significant weight loss or extreme dieting
Emotional trauma such as divorce, death of a loved one, or job loss
Chronic sleep deprivation

Another stress-related hair loss condition is trichotillomania, a psychological disorder where individuals compulsively pull out their hair as a response to negative emotions, tension, or anxiety.

Chronic stress also affects hormone levels, potentially exacerbating conditions like androgenetic alopecia. Additionally, stress can contribute to scalp problems like seborrheic dermatitis, which may indirectly affect hair growth and retention.

Diet-related hair loss causes stem from nutritional deficiencies that impair follicle function. Your hair requires adequate protein, vitamins, and minerals to maintain its growth cycle. Crash diets, eating disorders, and highly restrictive food plans often result in noticeable hair thinning. Even moderate but persistent nutritional deficiencies can gradually affect hair quality and quantity over time.

Medical Conditions and Treatments

Various health conditions can trigger hair loss as either a primary symptom or secondary effect. Autoimmune diseases causing hair loss occur when the immune system mistakenly attacks hair follicles or related structures.

Alopecia areata causes include immune cells attacking hair follicles, resulting in patchy hair loss that can affect the scalp or entire body. This condition can range from small, isolated patches to complete loss of all body hair (alopecia universalis). While the exact trigger remains unclear, genetic factors and environmental stressors likely play roles in its development.

Lupus, psoriasis, and scleroderma represent other autoimmune conditions that may cause inflammation affecting the skin and hair follicles. These conditions can lead to scarring alopecia, where hair follicles are permanently damaged and replaced by scar tissue, preventing future hair growth in affected areas.

Hair loss from medications is a common side effect of various treatments. Chemotherapy drugs target rapidly dividing cells, including cancer cells and, unfortunately, hair follicle cells. Other medications associated with hair loss include:

Blood thinners
Antidepressants
Retinoids
Beta-blockers
Anti-inflammatory drugs
Anticonvulsants

Hair loss from scalp infections such as ringworm (tinea capitis) can cause patches of hair loss accompanied by broken hairs, scaling, and inflammation. Bacterial infections and folliculitis can also damage hair follicles if left untreated. While most infection-related hair loss resolves with appropriate treatment, severe or chronic infections may lead to scarring and permanent hair loss.

Nutritional Deficiencies and Environmental Factors

Hair loss due to vitamin deficiency reflects the complex nutritional requirements of hair follicles. Several key nutrients play crucial roles in maintaining healthy hair growth cycles.

Iron deficiency represents one of the most common nutritional causes of hair loss, particularly in women with heavy menstrual bleeding, pregnant women, or those following restrictive diets. Iron is essential for producing hemoglobin, which carries oxygen to cells throughout the body, including hair follicles. Without adequate oxygen, follicles cannot support normal hair growth.

Vitamin D deficiency has been linked to alopecia areata and other forms of hair loss. This vitamin plays a role in hair follicle cycling and immune function. Other nutritional deficiencies associated with hair loss include:

Zinc: Supports tissue growth and repair
Biotin: Essential for keratin production
Vitamin E: Provides antioxidant protection
Omega-3 fatty acids: Reduce inflammation and support scalp health
Protein: Provides the building blocks for hair strands

Environmental causes of hair loss include exposure to pollutants, harsh styling practices, and chemical treatments. UV radiation from sunlight can damage hair proteins and weaken strands, leading to breakage. Chlorine in swimming pools can strip natural oils and proteins from hair, making it brittle.

Heat styling tools, tight hairstyles, chemical straightening, and coloring treatments can damage the hair shaft and, in some cases, the follicles themselves. Traction alopecia results from hairstyles that pull on the roots, such as tight ponytails, braids, or extensions, eventually damaging follicles permanently if the tension continues long-term.