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Rsm4.0

Rosemary Oil (topical) Research

Mostly mechanism / observationalHigh safety

4 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most Rosemary Oil (topical) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from mixed-quality randomised trials published 1998–2023 with a typical study size of 100 participants.

Based on 4 studies · 2 RCTs · 186 total participants

Confidence

Low

By outcome

Hair & nails
Mostly mechanism / observational4 studies
Men's vitality
Too few graded studies1 study
Safety profile
Too few graded studies1 study

Steady research

1 study in the last 5 years

199820102023

1Systematic Review2023

Inconsistent or poorly reported study methodology and nonstandardized outcomes limit the conclusions that can be made from these studies.

Tkachenko E, Okhovat JP, Manjaly P, Huang KP, Senna MM, Mostaghimi A. · J Am Acad Dermatol (2023)

Systematic review: of 1015 citations, 16 studies met inclusion; essential-oil aromatherapy was among the complementary therapies with the 'best' (but sparse, low-quality) evidence for hair growth
Reviewers explicitly cautioned that inconsistent, poorly reported methodology and nonstandardized outcomes limit any firm conclusions
Adverse events across these therapies were rare and mild, supporting a favourable topical safety profile

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2RCTn=100 · medium study2015

Both groups experienced a significant increase in hair count at the 6-month endpoint compared with the baseline and 3-month endpoint; no significant difference was found between the study groups regarding hair count either at month 3 or month 6.

Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A. · Skinmed (2015)

Randomized comparative trial: 100 patients with androgenetic alopecia assigned to rosemary oil (n=50) or minoxidil 2% (n=50) for 6 months
Both groups had comparable, statistically significant increases in hair count, with no significant between-group difference at month 3 or month 6
Neither group improved at 3 months; scalp itching was more frequent with minoxidil than rosemary oil

3RCTn=86 · small study1998

The active group massaged essential oils (thyme, rosemary, lavender, and cedarwood) in a mixture of carrier oils (jojoba and grapeseed) into their scalp daily. The control group used only carrier oils for their massage, also daily.

Hay IC, Jamieson M, Ormerod AD. · Arch Dermatol (1998)

7-month double-blind RCT for alopecia areata: 86 patients; the active essential-oil group improved in 19/43 (44%) vs 6/41 (15%) of carrier-oil controls (P=.008)
The intervention was a COMBINATION of thyme, rosemary, lavender, and cedarwood oils — not rosemary alone — so benefit cannot be attributed to rosemary specifically
Treats alopecia areata (autoimmune patchy loss), a different condition from androgenetic (pattern) hair loss

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4Animal2013

Topical administration of Rosmarinus officinalis leaf extract (RO-ext, 2 mg/day/mouse) improved hair regrowth in C57BL/6NCrSlc mice that experienced hair regrowth interruption induced by testosterone treatment.

Murata K, Noguchi K, Kondo M, Onishi M, Watanabe N, Okamura K, Matsuda H. · Phytother Res (2013)

Topical rosemary leaf extract restored testosterone-suppressed hair regrowth in mice and promoted regrowth in shaved mice, supporting an anti-androgenic mechanism
Rosemary extract inhibited testosterone 5-alpha-reductase by 82.4% and 94.6% at 200 and 500 µg/mL in vitro; 12-methoxycarnosic acid was identified as an active constituent
The extract also inhibited androgen-dependent cell proliferation, suggesting interference with DHT-androgen-receptor signalling

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View in Research Library

Rosemary Oil (topical) Research

Mostly mechanism / observational

Complementary and alternative medicine for alopecia areata: A systematic review.

Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial.

Randomized trial of aromatherapy. Successful treatment for alopecia areata.

Promotion of hair growth by Rosmarinus officinalis leaf extract.