Encyclopedia · drug with hair side effects
Hydroxychloroquine
A malaria and lupus drug that is the most-used pill for scarring alopecias such as lichen planopilaris and frontal fibrosing alopecia, with no randomized trial behind it, and whose cousin chloroquine can lighten hair colour.
What it is
A prescription antimalarial and anti-rheumatic. Use for hair is off-label. Prescription-only in the US, EU and UK.
How it works
Immune calming in lymphocyte-driven scarring alopecias. The exact mechanism in hair is not established.
What the studies show
- A systematic review of lichen planopilaris and frontal fibrosing alopecia (114 FFA patients) found no randomized trial. Hydroxychloroquine gave a good response in 30% of 29 patients, against 45% for oral 5-alpha-reductase inhibitors. Racz 2013
- In a 2025 retrospective cohort of 315 patients, hydroxychloroquine was the most-used systemic drug (65.2% of lichen planopilaris and 57.8% of FFA patients), while the highest response rates were for methotrexate (79.2% in lichen planopilaris) and retinoids (73.9% in FFA). Its own response rate was not in the abstract. Willaert 2025
- A systematic review of 94 articles (689 reactions) found hair loss reported 12 times, behind rash, pigmentation and itch. Sharma 2020
- A 1992 review found chloroquine and chemotherapy had the best evidence for causing hair colour changes. Bublin 1992
How it's used in studies
Doses were not extracted from the abstracts.
Side effects and safety
Rare retinal toxicity needs eye screening. Skin reactions, pigment changes and hair loss are reported.
Bottom line
Widely used for scarring alopecia on observational evidence with modest response; not for pattern baldness or ordinary shedding. Discuss with a doctor.
Fun facts
- A lupus drug is the most-used pill for frontal hairline-recession scarring in women, though it has never been tested against placebo, and the related chloroquine can bleach hair. Bublin 1992
Studies 4
Racz E et al. Treatment of frontal fibrosing alopecia and lichen planopilaris: a systematic review. J Eur Acad Dermatol Venereol. 2013
Result: No randomized trial; hydroxychloroquine gave a good response in 30% of 29 patients, 5-alpha-reductase inhibitors 45%.
Read the study ↗Willaert M et al. Systemic treatments for lichen planopilaris and frontal fibrosing alopecia: a retrospective study. Acta Derm Venereol. 2025
Result: Hydroxychloroquine was the most-used systemic drug (65.2% LPP, 57.8% FFA); best response rates were methotrexate (LPP 79.2%) and retinoids (FFA 73.9%).
Read the study ↗Sharma AN et al. Adverse dermatologic effects of hydroxychloroquine: a systematic review. J Am Acad Dermatol. 2020
Result: Hair loss was reported 12 times, behind rash, pigmentation and itch.
Read the study ↗Bublin JG, Thompson DF. Drug-induced hair colour changes. J Clin Pharm Ther. 1992
Result: Chloroquine and chemotherapy had the best evidence for causing hair colour changes.
Read the study ↗Related
- MethotrexateA weekly immune-suppressing medicine that thins hair in a few percent of users, and is also used off-label for severe alopecia areata.
- Cyclosporine (ciclosporin)A transplant and psoriasis immunosuppressant that makes hair grow as a side effect and works off-label in alopecia areata, but is toxic to kidneys and blood pressure.
- TofacitinibThe first JAK inhibitor used off-label for alopecia areata; about a third to two thirds of patients regrow hair in open-label studies, but most relapse within months of stopping.
- IsotretinoinA prescription acne drug that causes shedding in a few percent of users and, far more seriously, severe birth defects.
- Lichen planopilarisAn immune-mediated scarring hair loss, mainly on the crown and sides, that destroys follicles permanently; early treatment aims to stop activity because lost hair does not return.
- Frontal fibrosing alopeciaA scarring hair loss that pulls the front and temple hairline back, often with eyebrow thinning; lost follicles do not return, so treatment aims to stop progression early.