Question & Answer

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Claims have been made that rosemary oil can help reduce hair loss or hair thinning and some products are marketed with this claim.
We found no high-quality evidence that rosemary oil reduces hair loss or hair thinning when compared to no treatment.
We found one small randomised trial with 100 people that suggested that rosemary oil was as effective as minoxidil 2% (Regaine; registered trade mark of Johnson & Johnson Limited). This study found a significant increase in hair count at 6-month in both the group of people who had been allocated to use rosemary oil and those who had been allocated to use minoxidil 2%. This difference in hair count was not present at the 3-month check.
We found no national (Health Service Executive) or international (World Health Organization, Centers for Disease Control and Prevention) guidelines on using rosemary oil for hair loss or hair thinning.
We need further high-quality research before we can be certain about the effectiveness of rosemary oil on hair loss or thinning.

Opinions alone are not a reliable basis for claims about the effects of treatments.
Just because a treatment claim is made by someone in authority, you cannot be sure that it is trustworthy unless it is clearly based on a summary of fair comparisons.
Always ask yourself whether the possible advantages of treatment outweigh the disadvantages of the treatment.

Lead Researcher: Dr. Petek Eylül Taneri, Post-Doctoral Researcher, University of Galway
Reviewed by: Prof. Declan Devane, School of Nursing and Midwifery, HRB-Trials Methodology Research Network, Evidence Synthesis Ireland & Cochrane Ireland, University of Galway
Topic advisor: Dr. Darren Dahly, Principal Statistician, HRB Clinical Research Facility, Cork, Ireland, and Senior Lecturer in Research Methods in the UCC School of Public Health.
Public and Patient advisor: Deirdre Mac Loughlin, Public and Patient Involvement in research (PPI) advisor, PPI Ignite, University of Galway.
Journalist Advisor: Dr Claire O’Connell, Science communicator and contributor to The Irish Times.

Conflict of Interest Statement: The authors have no financial or other conflicts of interest for this health claim summary.