Reasons for Hair Loss
Discover the main reasons for hair loss, from genetics and stress to nutrient deficiencies. Learn the difference between hair shedding and hair loss.
Reviewed 1 Oct 2026
Hair Library · Category
Hair Loss
The patterns, causes and stages of hair loss, the scales doctors use to describe them, and hair loss linked to hormones, pregnancy and medicines.
Entries
DHT and Hair Loss
DHT hair loss happens when genetically sensitive follicles shrink over time. Learn the early signs, how specialists diagnose it, and which treatments can slow it down.
Norwood Scale: Stages 1–7
The Norwood scale stage by stage: Norwood 1, 1.5 and 2 to 7, the 3 vertex and type A patterns, how common each stage is and what it means for treatment.
Reviewed 13 Oct 2026
Norwood Test & Graft Calculator
Pick the picture closest to the top of your head to see your Norwood stage and the graft range our medical team plans from. Free, no sign-up, not a diagnosis.
Reviewed 8 Jul 2026
Crown Balding
Crown balding explained: a normal crown vs a thinning one, the stages of crown hair loss, its causes, and the treatments and transplant options with evidence.
Reviewed 13 Oct 2026
Mature Hairline
Mature hairline or receding hairline? What Norwood 2 means, when a hairline matures, four checks to compare at home and when to see a doctor about it.
Reviewed 23 Oct 2026
Thyroid and Hair Loss
Can thyroid problems cause hair loss? How hypo and hyperthyroidism, Hashimoto's and levothyroxine affect hair, when it grows back and which tests to ask for.
Reviewed 23 Oct 2026
Postpartum Hair Loss
Postpartum hair loss explained: why it happens after birth, when the shedding peaks and stops, and how to support healthy regrowth without unnecessary panic.
Reviewed 7 Jul 2026
Mounjaro and Hair Loss
Does Mounjaro cause hair loss? Label rates for Mounjaro, Zepbound, Wegovy and Ozempic vs placebo, why shedding starts, how long it lasts and if hair grows back.
Reviewed 23 Oct 2026
Adderall and Hair Loss
Does Adderall cause hair loss? What the FDA label and trials show about appetite, weight and sleep, why shedding starts months later, and what to ask.
Reviewed 13 Oct 2026
Wellbutrin and Hair Loss
Wellbutrin hair loss explained: what the bupropion label and a 1 million patient study show, when shedding starts, how long it lasts, and what to ask.
Reviewed 13 Oct 2026
Birth Control and Hair Loss
Can birth control cause hair loss? Learn how the progestin type affects shedding, how long hair loss lasts after stopping the pill, and which options are least likely.
Reviewed 14 Sep 2026
Planned entries
Topics this category still needs. Each is written from peer-reviewed sources and medically reviewed before it is published.
Androgenetic AlopeciaFemale Pattern Hair LossTelogen Effluvium
Key terms
What is alopecia areata?
Alopecia areata is an autoimmune condition that can cause round patches of hair loss in the eyebrows, beard or scalp. Hair often regrows within a few months and may look white or grey at first before the natural colour returns.
Full entry: Do Eyebrows Grow Back? →What is androgenetic alopecia?
Androgenetic alopecia, or pattern baldness, is the pattern hair loss behind most male and female thinning. It is primarily driven by genetic predisposition and sensitivity to androgen hormones.
Full entry: DHT and Hair Loss →What is the crown (vertex)?
The crown, also called the vertex, is the highest point at the back of the head, where hair grows out in a spiral. Crown and vertex are two names for the same area.
Full entry: Crown Balding →What is DHT?
Dihydrotestosterone (DHT) is a potent androgen that the body makes from testosterone using an enzyme called 5-alpha reductase. In people who are genetically sensitive to it, DHT makes hair follicles shrink.
Full entry: DHT and Hair Loss →What is a mature hairline?
A mature hairline is the slightly higher, more shaped hairline most men develop as they move from their teens into adulthood. It is a change in shape, not a loss of density.
Full entry: Mature Hairline →What is the Norwood scale?
The Norwood scale is the classification most doctors use for male pattern hair loss. It describes the usual ways the loss moves, stage by stage, from Norwood 1 to Norwood 7.
Full entry: Norwood Scale: Stages 1–7 →What is postpartum hair loss?
Postpartum hair loss is heavier-than-normal shedding after giving birth, medically termed postpartum telogen effluvium. It is considered a normal response to hormonal change, not a disease.
Full entry: Postpartum Hair Loss →What is telogen effluvium?
Telogen effluvium is sudden diffuse shedding that follows illness, childbirth or stress. Shedding usually starts two to three months after the trigger, and it is usually self-limiting once the trigger is removed.
Full entry planned: Telogen Effluvium