Hair loss is a common concern that affects people of all ages and genders. While it’s often associated with ageing or genetics, hair loss can also be a symptom of underlying health issues that need attention. What may start as a few extra strands in the shower drain can evolve into noticeable thinning, bald patches, or complete hair fall—sometimes suddenly, sometimes gradually. But either way, it’s your body signalling something deeper.
Many individuals overlook hair loss as merely a cosmetic concern. However, your hair is closely tied to your body’s overall health. Factors like hormonal imbalances, nutritional deficiencies, autoimmune conditions, chronic stress, and thyroid problems can all manifest through your scalp and hair. That’s why understanding the root causes not just treating the symptom is key to finding lasting solutions.
In this comprehensive guide, we’ll explore major 7 health reasons behind hair loss. For each cause, we’ll explain the mechanisms, signs to watch for, and how to manage or reverse the issue. Whether you’re dealing with excessive shedding, patchy hair loss, or thinning, recognising the underlying trigger can lead to more effective treatment and better health overall.
1. Hormonal Imbalances
Hormones control nearly every function in the body—including hair growth. When these chemical messengers are out of balance, your scalp often takes the hit. Both men and women experience hormone-related hair loss, though the patterns may differ.
How Hormones Affect Hair
Hair growth cycles through three main stages: growth (anagen), rest (telogen), and shedding (catagen). Hormonal changes can disrupt this cycle by shortening the growth phase and prolonging the resting phase, leading to more hair falling out than growing in.
Key Hormonal Triggers:
- Androgens (e.g., DHT): Dihydrotestosterone is a byproduct of testosterone that shrinks hair follicles in genetically predisposed individuals, leading to androgenetic alopecia or pattern baldness.
- Estrogen and Progesterone: During pregnancy, high estrogen levels promote thicker hair, but the drop post-birth can trigger dramatic shedding—known as postpartum hair loss.
- PCOS (Polycystic Ovary Syndrome): Women with PCOS often have high androgen levels, leading to hair thinning on the scalp and excess hair on the body.
- Menopause: Hormonal shifts during menopause can thin scalp hair and dry out the strands.
Signs of Hormonal Hair Loss:
- Gradual thinning at the crown or temples
- Hair that falls out in clumps during brushing
- Acne, weight gain, or irregular periods in women
- Increased body or facial hair
Diagnosis and Treatment:
A blood test can assess hormone levels. Depending on the results, treatment may involve birth control pills (for PCOS), hormone replacement therapy (for menopause), or anti-androgens like spironolactone. Minoxidil (Rogaine) may also be used topically to stimulate regrowth.
Lifestyle Support:
- Regular exercise
- Balanced diet rich in protein and healthy fats
- Stress management (yoga, meditation)
- Avoiding endocrine disruptors like BPA
Hormonal imbalances are among the most common—and treatable—reasons for hair loss. Identifying the cause can make regrowth not only possible but sustainable.
2. Nutritional Deficiencies
Your hair is made primarily of a protein called keratin, and like any tissue, it needs proper nutrition to grow and stay strong. A diet lacking key nutrients can starve your hair follicles and trigger shedding, brittleness, and stunted growth.
Essential Nutrients for Hair Health:
- Protein: Hair is 95% protein. Low intake leads to thinning and loss.
- Iron: Deficiency is one of the top causes of telogen effluvium (diffuse hair shedding), especially in women.
- Zinc: Crucial for hair follicle repair and DNA production.
- Biotin (Vitamin B7): Important for keratin production.
- Vitamin D: Helps create new hair follicles.
- Vitamin A and E: Regulate sebum production and antioxidant protection.
- Omega-3 Fatty Acids: Provide nourishment to the scalp and reduce inflammation.
Symptoms to Look For:
- Thinning across the scalp
- Dry, brittle hair
- Slower hair growth
- Nails breaking easily
- Fatigue or pale skin (in iron deficiency)
Common Risk Groups:
- Vegans and vegetarians
- Women with heavy menstrual cycles
- Individuals on crash diets or restrictive eating plans
- People with malabsorption disorders like celiac or Crohn’s disease
Diagnosis and Correction:
A simple blood panel can assess levels of iron, B12, vitamin D, and other key markers. Nutrient deficiencies are reversible with dietary changes, supplements, and sometimes IV therapy for severe cases.
Best Foods for Hair Growth:
- Eggs, fish, lean meat (protein + biotin)
- Spinach, legumes (iron + folate)
- Nuts and seeds (zinc, vitamin E)
- Avocados (healthy fats)
- Mushrooms and salmon (vitamin D)
What you eat shows up on your head. With the right nutrients, you can rebuild hair health from the inside out.
3. Thyroid Disorders
The thyroid gland, located at the base of your neck, produces hormones that regulate metabolism, energy, and tissue growth—including your hair follicles. When thyroid function is disrupted, it often reflects through your skin, nails, and particularly your hair.
Types of Thyroid Disorders Affecting Hair:
- Hypothyroidism (underactive thyroid): Slows metabolism and reduces the body’s ability to grow new hair, causing thinning, dryness, and scalp hair loss.
- Hyperthyroidism (overactive thyroid): Speeds up metabolism and may lead to diffuse hair shedding across the scalp.
- Hashimoto’s thyroiditis: An autoimmune condition that damages the thyroid, leading to hypothyroidism.
- Graves’ disease: An autoimmune form of hyperthyroidism.
Symptoms to Watch:
- Thinning hair or patches of loss
- Dry, brittle hair
- Changes in weight (gain or loss)
- Fatigue, mood swings
- Cold or heat intolerance
- Changes in menstrual cycle
How to Diagnose and Treat:
A thyroid panel (TSH, T3, T4, and antibodies) can detect imbalances. Treatment may include levothyroxine for hypothyroidism or anti-thyroid medication for hyperthyroidism. When thyroid levels are stabilised, hair often begins to regrow—though it may take a few months.
Additional Support:
- Iodine, selenium, and zinc support thyroid function
- Avoid excessive soy and gluten if you have Hashimoto’s
- Get 7–9 hours of quality sleep
- Limit stress to reduce hormonal disruption
Ignoring thyroid-related hair loss can delay treatment for a critical endocrine issue. Early testing and consistent medication can reverse symptoms and restore your hair’s strength.
4. Autoimmune Conditions
Autoimmune diseases occur when the immune system mistakenly attacks the body’s own tissues—including hair follicles. These attacks disrupt normal hair growth cycles, resulting in patchy, unpredictable hair loss or complete baldness.
Common Autoimmune Causes of Hair Loss:
- Alopecia areata: The immune system targets hair follicles, causing sudden patchy hair loss on the scalp or body.
- Lupus: An autoimmune disease that can cause hair thinning, scalp inflammation, and scarring alopecia.
- Psoriasis: When affecting the scalp, it can block follicles and trigger temporary shedding.
- Hashimoto’s thyroiditis or celiac disease: Indirectly impact hair through malabsorption or thyroid dysfunction.
Telltale Signs:
- Circular bald spots
- Rapid, sudden hair loss in chunks
- Scalp redness, scaling, or inflammation
- Hair loss elsewhere (eyebrows, eyelashes)
- Family history of autoimmune disease
Medical Diagnosis:
Doctors often run autoimmune panels, biopsy affected scalp areas, and check for associated symptoms. Alopecia areata is diagnosed visually, but lupus or others may require ANA testing and further imaging.
Treatment Approaches:
- Topical or injectable corticosteroids for inflammation
- Immunosuppressive medications like methotrexate
- Biologic therapies for advanced autoimmune disease
- Minoxidil may be used to stimulate regrowth
- Nutritional support and anti-inflammatory diets
Autoimmune-related hair loss can be unpredictable and emotionally challenging. However, early diagnosis and coordinated treatment can restore hair and prevent worsening immune complications.
5. Stress and Emotional Trauma
Stress doesn’t just affect your mood—it directly impacts your hair. Acute stress or long-term anxiety can shock the body’s systems, pushing hair follicles into a resting phase and triggering a condition called telogen effluvium.
What Is Telogen Effluvium?
Telogen effluvium is characterised by diffuse hair shedding across the entire scalp. It typically begins 2–3 months after a stressful event and may last up to six months. After this period, hair may regrow, though texture and volume can change.
Triggers Include:
- Sudden job loss, divorce, or bereavement
- Major surgery or illness
- Financial or caregiving stress
- Mental health disorders like depression and anxiety
- Chronic stress from overwork or burnout
Signs to Recognise:
- Hair coming out in handfuls while brushing or washing
- Noticeable thinning all over (not just in patches)
- No visible scalp inflammation or scarring
- Increased hair on your pillow or clothes
How to Manage It:
- Address the source of stress (therapy, lifestyle change)
- Incorporate relaxation techniques like mindfulness or yoga
- Prioritise consistent sleep and healthy meals
- Take biotin or adaptogenic herbs like ashwagandha (with guidance)
When to Seek Help:
If hair loss persists beyond 6 months or worsens, consult a dermatologist to rule out more serious conditions like alopecia areata or thyroid dysfunction.
Hair loss from stress is usually reversible, but it requires patience and lifestyle adjustments. Healing your mind can often heal your scalp, too.
6. Scalp Infections or Skin Conditions
Your scalp is skin—and like skin anywhere else, it’s prone to infections and conditions that affect hair follicles. If left untreated, these issues can cause significant damage, leading to patchy or widespread hair loss.
Common Scalp Issues:
- Tinea capitis: A fungal infection (scalp ringworm) causing scaly, bald patches.
- Seborrheic dermatitis: Causes flaky, itchy scalp and can weaken hair roots.
- Folliculitis: Inflammation or infection of hair follicles.
- Scalp psoriasis: Thick plaques and scaling can restrict follicle function.
Warning Signs:
- Itchy, inflamed, or painful scalp
- Red or scaly patches
- Pus-filled bumps or crusting
- Hair breaking off at the root
- Unpleasant odour or discharge
Risk Factors:
- Sharing hair brushes or hats
- Poor hygiene or infrequent washing
- Sweating or excessive oil production
- Immune suppression or diabetes
Diagnosis and Treatment:
Dermatologists diagnose with a scalp exam, skin scrapings, or fungal culture. Treatments may include:
- Antifungal shampoos or oral medication
- Steroid creams or medicated washes
- Antibiotics for bacterial infections
- Coal tar or salicylic acid for scalp psoriasis
Maintaining good scalp hygiene, not sharing hair tools, and using appropriate products are essential for preventing recurrence. If you’re losing hair and your scalp feels off—treat it early to save your strands.
7. Chronic Illness and Medications
Some hair loss is a side effect of chronic diseases or the medications used to treat them. These effects are often overlooked but should be addressed, especially if they’re affecting your quality of life.
Diseases Linked to Hair Loss:
- Diabetes: Poor blood flow and insulin resistance can affect follicle function.
- Kidney and liver disease: Toxin buildup and nutritional imbalances damage hair health.
- Cancer: Chemotherapy and radiation commonly cause hair loss.
- Anemia: Low iron levels impair oxygen delivery to hair roots.
Medication-Induced Hair Loss:
- Chemotherapy drugs like doxorubicin, paclitaxel
- Beta-blockers and blood thinners
- Antidepressants and anticonvulsants
- Retinoids and hormone therapies
Signs It’s Medication-Related:
- Hair loss starts weeks or months after beginning a new drug
- Diffuse shedding without inflammation
- Hair regrowth once medication is stopped or switched
What to Do:
- Never stop medication without medical advice
- Discuss alternatives with your doctor
- Use scalp-strengthening shampoos and conditioners
- Take supportive supplements like B vitamins, zinc, and collagen
If hair loss is drug-related, it may reverse once treatment ends. In chronic illnesses, consistent disease management can often reduce hair loss as the body stabilises.
Conclusion:
Hair loss is more than a cosmetic issue it’s often your body’s first clue that something isn’t quite right. Whether it’s sudden shedding, gradual thinning, or noticeable bald patches, it’s essential to look beyond the surface and investigate the underlying health reasons behind it.
We’ve explored seven major causes of hair loss linked to health: hormonal imbalances, nutritional deficiencies, thyroid disorders, autoimmune conditions, stress, scalp infections, and chronic illnesses or medications. Each of these factors affects hair growth in a different way, but all share one thing in common—they can be managed or treated when identified early.
Your hair health is a mirror of your internal health. If your hormones are fluctuating, if your diet is lacking, or if your immune system is attacking your follicles, your hair will show it. That’s why treating hair loss at the root—literally and figuratively—is far more effective than just using topical products or cosmetic fixes.
Taking action starts with awareness. Notice your symptoms. Don’t ignore ongoing hair shedding, unexplained fatigue, skin changes, or sudden weight fluctuations. A simple blood test, scalp exam, or lifestyle assessment can uncover the cause.
And remember, regrowth takes time. Once the root issue is addressed—whether it’s nutritional, hormonal, or autoimmune-related—your hair can begin its recovery. Support your body with healthy habits, stay consistent with treatment, and give your follicles the care they deserve.
You don’t have to accept hair loss as inevitable. With the right diagnosis and a holistic approach, you can reclaim control, restore confidence, and bring life back to your hair—starting today.