Hair loss affects millions of people, and the causes range from medical conditions to everyday habits. Dermatologists point to several common culprits worth understanding.
Thyroid disorders rank among the most frequent medical causes. Both hyperthyroidism and hypothyroidism can trigger hair shedding because thyroid hormones regulate the hair growth cycle. When thyroid function drops, hair follicles shift prematurely into the shedding phase. Blood tests can reveal thyroid issues, and treatment often restores hair growth once hormone levels stabilize.
Medications frequently cause hair loss as an unintended side effect. Certain blood pressure medications, anticoagulants, and some psychiatric drugs can disrupt the hair cycle. Patients experiencing sudden shedding should review their medication list with their doctor rather than stopping drugs on their own.
Iron deficiency deserves attention because many people dismiss it as minor. Low iron impairs the body's ability to produce keratin, the protein that strengthens hair. A simple blood test identifies deficiency, and supplementation or dietary changes can reverse hair loss over several months.
Stress triggers a specific type of shedding called telogen effluvium. During physical or emotional stress, hair prematurely enters the resting phase before falling out. This typically occurs two to three months after the stressful event. Hair usually regrows once stress levels decrease.
Nutritional deficiencies beyond iron also matter. Insufficient protein, B vitamins, and zinc all support healthy hair growth. Restrictive diets and certain eating disorders can deplete these nutrients quickly.
Hormonal fluctuations affect hair, particularly in women. Pregnancy, menopause, and hormonal contraceptives can shift hair cycles. These changes are usually temporary, though some people experience longer-term shedding.
Pattern baldness remains the most common cause overall, affecting roughly