Onion Juice for Hair Loss: The Limits Behind the 87% Regrowth Claim

An onion-juice regrowth percentage needs a diagnosis beside it. Alopecia areata causes patchy hair loss, and some people regrow hair without treatment. The American Academy of Dermatology¹ recommends assessing the type, extent and duration of loss before choosing a treatment.¹

The 87% figure counted people who completed follow-up

The 2002 Baghdad study² compared crude onion juice with tap water in recent patchy alopecia areata. Participants applied their assigned treatment twice daily for two months. Chronic and severe forms were excluded.²

Of 45 onion recipients, only 23 completed follow-up; 15 of 17 controls completed. Reported full regrowth at eight weeks occurred in 20 of 23 onion completers, about 87%, versus 2 of 15 controls. Reasons for leaving were unknown, weakening confidence in that benefit estimate.²

Only seven onion-group completers were female. The paper describes a single-blind comparison but does not describe random allocation. Mild redness occurred in 14 of the 23 onion recipients. This was neither a large women’s trial nor evidence that irritating a scalp improves other forms of hair loss.²

A newer four-plant extract is a different intervention

Cinainu contains extracts of onion, lemon, guarana and cocoa. It is a formulated topical solution, rather than crude onion juice.³

Its RAAINBOW trial randomized 107 children and adolescents to treatment or placebo for 24 weeks, followed by 24 weeks without treatment. The paper appeared online in 2025 and in a January 2026 journal issue. Its primary analysis included 62 participants meeting the authors’ specified criteria for moderate-to-severe alopecia areata.⁴

The authors reported better relative improvement in the scalp hair-loss score with Cinainu (P = 0.0488). Several authors were affiliated with Legacy Healthcare, the developer. This result concerns a selected analysis of a particular mixture in children; it cannot identify onion’s individual contribution or establish a benefit for adult pattern thinning.⁴

The regulator reached a less favorable conclusion

The European Medicines Agency³ assessment found no statistically significant treatment difference in the analysis of all randomized participants: P = 0.35. It considered the smaller analysis and its borderline result insufficiently convincing. It also raised concerns about changes to the analysis population, unequal dropouts, product quality and whether the proposed marketed preparation matched the trial product.³

That disagreement matters when a positive trial result is presented as settled proof. The published authors treated the 62-person group as the relevant severity population. The regulator did not accept that restricted group as sufficient to establish effectiveness for authorization.⁴³

The company withdrew the EU application on 26 February 2025, during re-examination of an earlier recommendation to refuse authorization. This was a withdrawn application for a specific children’s medicine, not a ban on every onion-containing cosmetic. It also does not validate homemade juice.⁵

Get the hair-loss pattern named before testing a remedy

For a new bald patch, arrange a dermatology assessment rather than assuming a kitchen treatment fits. The Academy describes examining the scalp, skin and nails, sometimes with further tests. Depending on the situation, options may include observation, corticosteroid treatment or other therapies. Watchful waiting for a few recent patches is a decision made after assessment.¹

Ask: “Is this alopecia areata, pattern thinning, shedding or breakage? Which finding makes you think so? What outcome should we track, and when should we review it?” A photograph can help describe the change without treating an online percentage as your predicted result.

The “The Hair Check” section of Hair, Everywhere separates those patterns and directs round patches and scarring signs toward a dermatologist. Use its categories to describe where hair is missing, when it changed and whether hairs are shedding whole or snapping. Our guide to alopecia areata explains that diagnosis in more detail.