Hair Loss
Also known as: Androgenetic Alopecia / Hormonal Hair Loss
Hair loss affects approximately 80 million Americans. For most people, it is not purely cosmetic — it is a signal that something hormonal has shifted. In men, DHT-driven androgenetic alopecia is the primary cause. In women, hair loss is more complex, involving estrogen decline, thyroid dysfunction, iron deficiency, and shifting androgen ratios. Understanding the mechanism is essential for effective treatment.
In this article
Hair Loss in Men
Male pattern baldness (androgenetic alopecia) affects ~50% of men by age 50. The primary driver is DHT (dihydrotestosterone) — converted from testosterone by 5-alpha reductase.
- DHT binds to receptors in scalp follicles, causing miniaturization
- Pattern follows DHT-sensitive distribution: hairline and crown
- Genetic predisposition determines susceptibility
- TRT may accelerate hair loss in genetically predisposed men — DHT blockers (finasteride) can be used alongside
Hair Loss in Women
- Estrogen decline: Estrogen extends hair growth phase. As estrogen drops during perimenopause/menopause, hair spends less time growing and more time shedding.
- Androgen ratio shift: As estrogen declines, the relative influence of androgens increases, causing diffuse thinning across the top of the scalp.
- Thyroid dysfunction: Both hypothyroidism and hyperthyroidism cause diffuse hair loss. Eyebrow thinning (outer third) is a classic sign.
- Iron deficiency: Ferritin below 50 ng/mL is associated with hair loss even with normal hemoglobin.
- Telogen effluvium: Stress-triggered shedding 2-3 months after a triggering event (illness, surgery, emotional stress, post-partum).
Recommended Testing
- Total and free testosterone, DHT, DHEA-S
- Estradiol, progesterone (women)
- TSH, Free T3, Free T4, thyroid antibodies
- Ferritin (aim for >50 ng/mL)
- Vitamin D, zinc, biotin
- CBC (anemia screening)
Treatment
Hormonal
- HRT for women (restoring estrogen can slow or reverse menopausal hair loss)
- Thyroid optimization
- Iron supplementation if ferritin is low
Medical
- Minoxidil (topical, FDA-approved for men and women)
- Finasteride (men — blocks 5-alpha reductase, reduces DHT ~70%)
- Spironolactone (women — anti-androgen)
- Low-dose oral minoxidil (growing evidence)
Supportive
- Biotin (5,000 mcg daily), collagen peptides, zinc
- Gentle hair care — avoid excessive heat and tight styles
Act early. Hair loss treatment is more effective when started before follicles go dormant.
Related Conditions
Medical disclaimer: This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read on this website.
Medically reviewed. Last updated: March 2026.