Skin Health Skin Care & Cleansing Products Hair & Scalp Care The Common Causes of Excessive Hair Loss in Men By Jerry Kennard Updated on September 19, 2023 Medically reviewed by Susan Bard, MD Print If you're starting to go bald, it could feel like you're losing a piece of your identity. Understanding the cause of your excessive hair loss can help you decide if treatment options are right for you or if your hair will grow back. Here are some common causes of hair loss in men. becon / iStockPhoto Surgery or Illness If you recently underwent a major surgery or are recovering from a serious illness, hair loss is normal. Many people experience dramatic levels of hair loss some weeks after major surgery or after an illness. While the level of hair loss may appear excessive, it's really no more than a reaction to a specific event, and hair will return to normal after a period of time. Medications Some anticoagulants (medications that help stop the blood from thickening, or "clotting") and many chemotherapy drugs used in cancer treatments are well known for causing hair loss. Hair usually returns once the medication stops. Some antidepressants also may result in hair loss, and too much vitamin A can have the same effect. Hormonal medications, especially testosterone, can cause male or female pattern hair loss. Can Food Allergies Cause Hair Loss? Hormonal Imbalances Testosterone is a hormone that's responsible for deeper voices, muscular growth, and sex drive, among other things. When your body converts testosterone to the less useful dihydrotestosterone (DHT), you can experience hair loss. DHT attacks and shrinks hair follicles and may result in hair thinning or hair loss. Thyroid Issues Patients with hyperthyroidism or hypothyroidism often experience hair loss due to a speeding up of the conversion of testosterone to DHT. Even people who are undergoing thyroid treatment are not immune from the hair loss associated with their condition. Thyroid Disease Stress If you've been under a lot of pressure at work or at home, you might be able to blame your hair loss on stress. Excessive physical or emotional stress can cause hair to stop growing normally, falling out two or three months later. Luckily, hair loss due to stress is usually not permanent. Alopecia Areata Alopecia areata is an autoimmune condition that is also exacerbated (made worse) by stress. It causes hair to fall out in round patches on the scalp and elsewhere on the body due to your immune system attacking hair follicles. About 5% of people with alopecia will lose hair on their entire scalp. Typically, hair grows back, but it's common for hair loss to reoccur. Does Hat Tightness Cause Hair Loss? Other Causes Certain fungal infections can result in hair loss. Losing your hair may also signal some underlying problem, such as diabetes or lupus. As it is not always possible to assess the cause of rapid or excessive hair loss, it is always worth seeking medical advice to diagnose the cause of your hair loss. Shampoo Ingredients That Can Cause Hair Loss 7 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Phillips TG, Slomiany WP, Allison R. Hair Loss: Common Causes and Treatment. Am Fam Physician. 2017;96(6):371-378. Watras MM, Patel JP, Arya R. Traditional anticoagulants and hair loss: a role for direct oral anticoagulants? A review of the literature. Drugs Real World Outcomes. 2016;3(1):1-6. doi:10.1007/s40801-015-0056-z Goldstein BG, Goldstein AO. Patient education: Androgenetic alopecia in men and women (Beyond the Basics). UpToDate. Urysiak-czubatka I, Kmieć ML, Broniarczyk-dyła G. Assessment of the usefulness of dihydrotestosterone in the diagnostics of patients with androgenetic alopecia. Postepy Dermatol Alergol. 2014;31(4):207-15. doi:10.5114/pdia.2014.40925 Vincent M, Yogiraj K. A descriptive study of alopecia patterns and their relation to thyroid dysfunction. Int J Trichology. 2013;5(1):57-60. doi:10.4103/0974-7753.114701 Peters EMJ, Müller Y, Snaga W, et al. Hair and stress: A pilot study of hair and cytokine balance alteration in healthy young women under major exam stress. PLoS ONE. 2017;12(4):e0175904. doi:10.1371/journal.pone.0175904 Pratt CH, King LE, Messenger AG, Christiano AM, Sundberg JP. Alopecia areata. Nat Rev Dis Primers. 2017;3:17011. doi:10.1038/nrdp.2017.11 Additional Reading American Academy of Dermatology. Alopecia Areata: Overview. By Jerry Kennard Jerry Kennard, PhD, is a psychologist and associate fellow of the British Psychological Society. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit