Hair loss is a complex condition with multiple possible triggers. In many cases, more than one factor contributes to the problem.
Genetic Hair Loss
Androgenetic alopecia, commonly known as pattern baldness, is the most common cause of hair loss in both men and women. It is driven by genetic sensitivity to dihydrotestosterone (DHT), a hormone that gradually shrinks hair follicles. Over time, affected follicles produce thinner hairs until growth eventually stops.
Related reading: Pattern Baldness and Androgenetic Alopecia.
Hormonal Changes
Hormonal imbalances can disrupt the natural hair growth cycle. Pregnancy, menopause, thyroid disorders, and conditions such as polycystic ovary syndrome often trigger increased shedding. In men, hormonal shifts can accelerate genetically predisposed hair loss.
Stress and Lifestyle Factors
Physical or emotional stress places strain on the body and hair follicles. Events such as illness, surgery, rapid weight loss, or emotional trauma may trigger telogen effluvium, a condition where a large number of hairs enter the shedding phase at once.
Learn more: Telogen Effluvium Causes and Recovery.
Nutritional Deficiencies
Hair follicles require proper nutrients to function normally. Low iron, vitamin D, zinc, or protein levels can weaken hair and increase shedding. Restrictive diets or sudden weight changes are common contributors, especially in women.
Medical Conditions and Medications
Autoimmune diseases, diabetes, scalp infections, and inflammatory conditions may interfere with healthy hair growth. Certain medications, including chemotherapy drugs, blood pressure medications, and antidepressants, may also contribute to hair thinning as a side effect.