In short
- Onset before 18 is usually treatable and often reversible.
- Rule out: iron deficiency, thyroid, PCOS, alopecia areata.
- Early male-pattern loss under 18 = start monitoring, not treatment.
- Emotional support matters as much as medical workup.
Hair loss in teenagers is under-discussed and over-worried. Most cases have identifiable, treatable causes — nutritional, hormonal, or autoimmune. A calm, structured workup with a trichologist familiar with adolescents saves months of anxiety.
Common causes by age
- 11–14: alopecia areata peaks; nutritional deficiency; traction from tight styles
- 14–17: PCOS onset in girls; onset of MPB in boys with strong genetics; body-image-driven undereating
- 17–19: exam-stress TE; contraceptive-related; onset of true FPHL in girls
The London workup for under-18s
Ideally with a trichologist who consults adolescents (not all do). History with parent present, examination, trichoscopy, and bloods (ferritin, TSH, vitamin D, B12, coeliac screen for TE-like presentations). PCOS workup for adolescent girls with androgenic patterns.
Treatment nuance under 18
Finasteride and dutasteride are not licensed under 18 and should not be routine. Minoxidil topical 5% is off-label but used in specialist clinics for confirmed early MPB. Alopecia areata is treated with the same protocols as adults, with paediatric dose adjustments.
An adolescent's hair-loss diagnosis is medical. The support around it is human.
Frequently asked
Common questions
Is teenage hair loss usually genetic?+
Sometimes — early MPB can begin at 17–18. But the majority of teen presentations have secondary causes worth checking first.
Can exam stress cause hair loss?+
Yes — classic TE 8–12 weeks after peak stress. Resolves within a year.
Should I take my teen to their GP first?+
Yes — for baseline bloods. Then a trichologist for scalp assessment if needed.
Keep reading
Related, trichologist-reviewed
Hair loss
Female hair loss in your 20s: the London causes and pathways
Hair loss in your 20s feels early because it is. But it is almost never one thing, and almost never untreatable.
Read
Hair loss
Stress hair loss in London: telogen effluvium decoded
Stress-induced shedding is the most common reason 25–40 year-old Londoners walk into a trichology clinic. Here is what is happening and what to do.
Read
Hair loss
Alopecia areata in London: the 2026 treatment landscape after JAK inhibitors
The alopecia areata conversation changed permanently the day JAK inhibitors were licensed. Here is what that means for London patients in 2026 — and what the treatment ladder still looks like below them.
Read