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Does onion juice regrow hair?

We found one clinical study of onion juice for hair loss. It was published in 2002, involved 38 people with alopecia areata, the autoimmune kind, and we found no attempt to repeat it. We found no test of onion juice on ordinary male or female pattern baldness, which is what most onion-juice advice is about.

What the 2002 study found

Sharquie and Al-Obaidi, two dermatologists in Baghdad, had 23 people with patchy alopecia areata apply crude onion juice to their patches twice a day, and 15 others apply tap water. After six weeks, 20 of the 23 in the onion group had regrowth of coarse hair. In the tap-water group, 2 of 15 did, after eight weeks. They published the result in the Journal of Dermatology.

Why the result is weaker than it sounds

The figure that circulates online, 87%, is those 20 of 23. It counts people who had any regrowth, not how much hair came back, so it does not mean 87% of patients got their hair back. The published summary does not say how patients were placed in each group, and onion juice smells strongly, so they would have known which one they were in. We found no attempt to repeat the study in the more than twenty years since.

What dermatology guidelines say

The British Association of Dermatologists' 2025 guideline on alopecia areata found insufficient evidence to recommend allium or onion ointment, according to the German S3 guideline published in 2026, which lists it among alternative treatments with too little evidence behind them.

Pattern baldness and red onion

We found no clinical study of onion juice in androgenetic alopecia, the hormone-driven thinning behind most hair loss in men and much of it in women. We found no study comparing red onion with any other onion, and no registered trial of any onion hair oil or shampoo.

Skin reactions

Onion can cause allergic contact dermatitis; case reports go back to the 1970s. Anyone who reacts to handling onions should not put the juice on their scalp.

Where onion does appear in the register

Two programmes from the Swiss company Legacy Healthcare contain onion extract, blended with three other plant extracts. CG 428 was tested in a small double-blind pilot in breast cancer survivors with permanent hair loss after chemotherapy: after six months, hair density was up 34.7% on the lotion and 24.9% on placebo. Coacillium, a blend of guarana, cacao, onion and lemon for alopecia areata, reached a European marketing application, which Legacy withdrew in February 2025 after a negative opinion from the regulator's scientific committee.

In the register

Sources

  1. Onion juice (Allium cepa L.), a new topical treatment for alopecia areata · Journal of Dermatology, 2002 · PMID 12126069
  2. S3 guideline diagnostics and therapy in alopecia areata – Part 2: Therapy, psychosocial and cosmetic support · Journal der Deutschen Dermatologischen Gesellschaft, 2026 · PMID 42076948
  3. British Association of Dermatologists living guideline for managing people with alopecia areata 2024 · British Journal of Dermatology, 2025 · PMID 39432739
  4. Impact of a topical lotion, CG428, on permanent chemotherapy-induced alopecia in breast cancer survivors: a pilot randomized double-blind controlled clinical trial (VOLUME RCT) · Supportive Care in Cancer, 2020 · PMID 31338640
  5. Contact allergy to onion · Contact Dermatitis, 1977 · PMID 891180

Checked against its sources on 2026-09-30, by us, not by a doctor. A research register, not medical advice: talk to a dermatologist about your own case. See why we're not doctors.