Encyclopedia
Every molecule that touches your hair
From proven medicines to kitchen-cupboard oils, with the studies behind each one.
11 entries
B
-
immunomodulator
Baricitinib
A once-daily pill that was the first drug approved for severe alopecia areata, regrowing hair in about a third of patients while they keep taking it.
-
growth stimulant
Bimatoprost
A prostaglandin-like eye medicine that grows longer, thicker, darker eyelashes (and helps eyebrows), but did not work on the scalp.
E
-
other
Eflornithine
A cream that slows hair growth by blocking the polyamine pathway, improving unwanted female facial hair in trials, with growth returning within 8 weeks of stopping.
-
drug with hair side effects
EGFR inhibitors (erlotinib, cetuximab)
Cancer drugs that block the EGF receptor can make eyelashes grow abnormally long and curly, and scalp hair curly or brittle, all reversing after the drug stops.
L
-
growth stimulant
Latanoprost
A cheap glaucoma eye drop that lengthens and darkens eyelashes, with only a small pilot trial behind its off-label use on the scalp.
M
-
growth stimulant
Minoxidil
The most widely used hair-growth treatment, available as a cheap over-the-counter lotion or foam and as a prescription tablet, with a mechanism that is still only partly understood.
P
-
drug with hair side effects
Phenytoin
The old epilepsy drug phenytoin is the best-documented anticonvulsant for causing excess facial and body hair, along with acne and gum overgrowth.
R
-
immunomodulator
Ritlecitinib
A once-daily pill approved for severe alopecia areata from age 12, which regrows hair in about 1 in 4 people by 6 months and keeps improving for years.
S
-
botanical
Spearmint
Spearmint tea lowered free testosterone in two small trials of women with excess hair growth, but no study has tested it for scalp hair loss.
T
-
drug with hair side effects
Topiramate
An epilepsy and migraine pill sometimes floated as a topical hair grower, although nobody has ever tested it on scalp hair; the real hair signals are reversible shedding, one case of overlong eyelashes and a small open trial in compulsive hair-pulling.
U
-
immunomodulator
Upadacitinib
A JAK1 pill already approved for other diseases that gave 45 to 55% of people with severe alopecia areata near-full scalp hair in two 2026 trials and is under regulatory review for hair.