Rosemary oil and hair: what the one trial actually measured
Last updated: 13 September 2026
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The trial everyone is quoting
Almost every video about rosemary oil and hair traces back to one study. It is worth knowing exactly what it did, because the video version and the paper version are not the same thing.
Panahi and colleagues published it in SKINmed in 2015. One hundred men with androgenetic alopecia were randomised into two groups of fifty. One group applied rosemary oil to the scalp, the other applied minoxidil 2%. The trial ran for six months and was single-blind. Hair count was measured by standardised microphotography at the start, at three months and at six months.
At three months, neither group had changed significantly. At six months both had improved against their own baseline: the rosemary group by 44 hairs and the minoxidil group by 40. The difference between the two groups was not statistically significant at either point.
One more result is usually left out: scalp itching was significantly more common in the rosemary group than in the minoxidil group, at three months and again at six.
What that does and does not establish
It is a real randomised trial and it is not nothing. It is also one trial, in one country, with one hundred men, one type of hair loss, and no placebo arm. Both arms improved; without a group applying a carrier alone, the trial cannot separate the oil from the massage, the carrier, or six months of paying attention to your scalp.
Single-blind means the assessors knew less than the participants did. Rosemary and minoxidil do not smell alike, so the men knew which they had been given.
So the honest sentence is: in one six-month trial, rosemary oil performed about as well as a low-dose minoxidil preparation, and itched more. That is genuinely interesting. It is not a licence to tell you it will regrow your hair.
Why I will not put a hair-growth claim on this site
Androgenetic alopecia is a medical condition. In Europe, telling you a product treats it makes that product a medicine, with everything that follows: an authorisation, a dossier, a regulator. A cosmetic may not carry that claim, and I am a Wellness Advocate, not a pharmacist or a dermatologist.
The European product information sheet for Rosemary lists topical and aromatic use. It does not claim anything about hair growth, and neither will I. If your hair is thinning in a way that worries you, the person to see is a dermatologist — there are treatments with far more evidence behind them than one trial of a hundred men.
If you want to try it anyway, do it properly
People will try it, and that is their decision to make. These are the parts I can help with.
- Dilute it. Never apply rosemary oil neat to the scalp. A 1–2% dilution in a carrier oil — roughly six to twelve drops in 30 ml — is the sensible range for skin.
- Patch test first. The itching finding in that trial is the most practical thing in it. Try a small area on the inner forearm and leave it 24 hours before putting anything on your scalp.
- It is not rosemary water. Rosemary essential oil, rosemary hydrosol and boiled rosemary sprigs are three different things at three different strengths. The trial used oil.
- Not in pregnancy without advice. Rosemary is one of the oils commonly listed as best avoided in pregnancy, and the general caution applies: ask a midwife or doctor first.
- Keep it off broken skin and away from the eyes. Scalp skin that is already irritated is not the place to start.
Common questions
Does rosemary oil work as well as minoxidil?
In the trial described above, the two groups ended up statistically indistinguishable after six months. One trial of a hundred men is not enough to say that generally, and minoxidil at 5% is the strength usually prescribed, not the 2% used here.
How long would it take?
In that trial, nothing measurable had happened at three months. Anyone promising results in three weeks is not describing this evidence.
Can I add it to my shampoo?
You can, but shampoo is rinsed off within a minute, which is not how the trial applied it. If you are going to try, a diluted scalp oil left on is closer to what was studied.
Is rosemary oil safe for everyone?
No. It is not recommended in pregnancy, and people with epilepsy are usually advised to avoid it. Diluted or not, it can irritate skin — which is exactly what the trial found.
Sources
- Panahi Y, Taghizadeh M, Tahmasbpour Marzony E, Sahebkar A. „Rosemary Oil vs Minoxidil 2% for the Treatment of Androgenetic Alopecia: A Randomized Comparative Trial.“ SKINmed, January/February 2015. pubmed.ncbi.nlm.nih.gov
- European Commission, Scientific Committee on Consumer Safety — opinion material on fragrance allergens and skin sensitisation. ec.europa.eu
- doTERRA European product information sheet for Rosemary, as published in the European shop that serves your country.
Checked 13 September 2026. Written by a Wellness Advocate, not a doctor, pharmacist or dermatologist. Nothing here is medical advice.
The oils mentioned on this page
Each product page lists the botanical name, the size, the directions and the cautions, with a buy button for your country.