Rosemary for Hair: What the Studies Really Show – and How to Make Your Own

A Mediterranean kitchen herb that supposedly holds its own against an established hair-growth treatment – that is the claim that has circulated online for a few years now. The short answer up front: the evidence is promising but incomplete – proof that rosemary works for hair growth is still missing. What the studies so far actually show, and how to make your own rosemary preparation for the scalp, is explained here.

Why is rosemary associated with hair growth in the first place?

Rosemary (botanically Salvia rosmarinus, formerly Rosmarinus officinalis) belongs to the mint family and is native to the entire Mediterranean region. As a culinary herb it has been known for centuries; in folk tradition, an infusion made from the leaves was also used as a scalp treatment and invigorating rinse for the hair. This long-standing traditional use is the starting point from which a distinct research field has developed in recent years: scientists are investigating whether, and through which mechanism, rosemary extracts might actually act on hair growth – among other things via the compounds carnosic acid, rosmarinic acid, and 12-methoxycarnosic acid.

A botanical side note: the name Rosmarinus officinalis is now considered taxonomically outdated; current databases list the plant as Salvia rosmarinus, placing it in closer relation to sage than previously assumed. This renaming changes nothing about its use – older and newer studies refer to the same plant.

What does the animal study show about a possible mechanism of action?

A frequently cited preclinical paper comes from Murata and colleagues (2013, Phytotherapy Research). In this animal study on mice, a topically applied rosemary leaf extract improved hair regrowth in animals whose hair growth had been artificially interrupted by testosterone. In additionally shaved mice, the extract likewise promoted fur growth. In laboratory testing, the extract showed an inhibitory effect on the enzyme 5-alpha reductase – the enzyme that converts testosterone into dihydrotestosterone (DHT), which is partly responsible for hereditary hair loss. 12-Methoxycarnosic acid was identified as the effective single compound. Important for context: this is an animal study using external, concentrated extract application. Results from mouse skin cannot be directly transferred to the human scalp, but they provide a plausible mechanistic explanation for why rosemary was tested in human research at all. On its own, this is not proof of an effect in humans – that requires the human studies described below.

What does the largest human comparison study show?

The most frequently cited human study is a randomized comparative trial by Panahi and colleagues (2015, the journal Skinmed). 100 people with androgenetic alopecia (hereditary hair loss) were treated over six months with either rosemary oil or a 2% minoxidil solution – 50 people per group. After three months, neither group showed a significant change in hair density. After six months, hair count had increased significantly in both groups compared with baseline, with no statistically meaningful difference between the groups. One safety aspect stood out: scalp itching occurred more often in both groups than at the start of the study, but was significantly more pronounced in the minoxidil group at both assessment points than in the rosemary group. For context, it is important that this study tested rosemary oil directly against an effective comparator medication but did not include an untreated control or placebo group. One can therefore say that, in this one study, rosemary oil performed similarly to low-dose minoxidil – not that either treatment is more effective than no treatment at all. The result is promising, but without a placebo comparison it does not amount to strict proof of efficacy.

What do more recent studies on rosemary oil blends show?

A review article by Al-Obaidi and colleagues (2024, the journal Cureus) summarises the current state of research on botanical alternatives for androgenetic alopecia and attributes several possible mechanisms of action to rosemary oil: antioxidant, antimicrobial, and anti-inflammatory properties, along with a possible improvement in scalp circulation that in some respects resembles the mechanism of minoxidil. This is a narrative review article, not an original study.

In 2025, a placebo-controlled, double-blind, three-arm study (also in Cureus, 90 participants, 90 days) compared a rosemary-lavender oil blend and a rosemary-castor oil blend against a coconut oil control. Using phototrichography – an objective measurement method – both rosemary groups showed a markedly stronger increase in hair growth rate from baseline (57.7% and 47.6% respectively) than the coconut oil group (21.1%), each statistically significant. Two caveats are important here for evidence transparency: first, these were multi-ingredient oil blends containing several active plant compounds, not isolated rosemary oil – the contribution of rosemary alone cannot be separated out from this study. Second, the tested formulation was a specific, commercially marketed product, which should be taken into account when weighing potential conflicts of interest. This is methodologically the strongest of the four studies discussed here, but proof of efficacy for isolated rosemary oil on its own remains outstanding.

Study	Study type	Design	Key finding
Murata et al., 2013	Animal study (preclinical)	Mice, topical application	5-alpha reductase inhibition as a possible mechanism
Panahi et al., 2015	RCT (human)	n=100, 6 months, rosemary oil vs. minoxidil 2%	Comparable hair increase, less itching than minoxidil
Al-Obaidi et al., 2024	Narrative review	Literature review	Summary of possible mechanisms of action
Patel et al., 2025	RCT (human), placebo-controlled	n=90, 90 days, 3 groups (oil blends vs. coconut oil)	Higher growth rate vs. placebo; multi-ingredient, product-specific formulation

How can you make a rosemary preparation for the scalp yourself?

If you would like to try the traditional approach at home, there are essentially two simple options. Important beforehand: a homemade preparation was not tested in any of the studies above and matches neither the concentration nor the standardisation of the rosemary oil used there – it follows traditional use, not a clinically tested protocol. Whether it produces a comparable effect is accordingly unproven.

Option 1 – Oil infusion (maceration): Place fresh or dried rosemary sprigs in a clean, sealable jar and cover them completely with a neutral carrier oil (e.g. jojoba or olive oil). Let the jar steep for 2 to 3 weeks in a dark, room-temperature spot, shaking occasionally. Then strain through a fine sieve or cheesecloth and pour into a dark bottle. For a quicker version, gently warm the oil and rosemary in a water bath for 1 to 2 hours instead (do not boil), then strain in the same way.

Option 2 – Rosemary water (infusion): Pour roughly half a litre of boiling water over 2 to 3 tablespoons of fresh or dried rosemary, cover and let steep for 15 to 20 minutes, strain, and let cool completely. This liquid works well as a final rinse after washing your hair.

To use the oil infusion, apply a small amount to the scalp and gently massage in for a few minutes; the oil can then be left on for 30 to 60 minutes or overnight, as preferred, before washing out. Rosemary water is usually used undiluted as a final rinse and does not need to be rinsed out. Both variants can be used 2 to 3 times per week.

On shelf life: an oil infusion stored in a dark, well-sealed bottle in a cool place typically keeps for several months; if the smell, colour, or consistency changes, it should be discarded. Rosemary water contains no alcohol or preservatives and is therefore considerably less stable – it should be kept in the fridge and used up within a few days. Both preparations are intended for private, personal use; commercially manufactured and sold cosmetic products are subject to separate legal requirements in Switzerland that go beyond the scope of a homemade preparation.

What should you keep in mind when using it?

A skin patch test is recommended before first use: apply a small amount to the inside of the forearm and wait 24 hours. Rosemary essential oil components, particularly camphor-containing rosemary chemotypes, should always be diluted and never applied undiluted to the skin; contact with eyes and mucous membranes should be avoided. Use is not advised for children under 6, during pregnancy and breastfeeding, or with known epilepsy, since camphor-containing preparations can have undesirable effects on the nervous system or uterine muscle in these situations. Caution is advisable with high blood pressure, since rosemary is associated with a circulation-stimulating effect in some sources. In cases of persistent, sudden, or strongly progressing hair loss, self-treatment does not replace a medical assessment of the underlying cause.

Conclusion: promising, but incomplete

Anyone looking for a simple answer to whether rosemary demonstrably promotes hair growth has to live with a both/and: the evidence is promising but incomplete. Promising, because an animal study provides a plausible mechanism of action, a randomized human study shows an effect comparable to low-dose minoxidil over six months with better tolerability, and a more recent placebo-controlled study supports a positive effect of rosemary oil blends. Incomplete, because none of these works alone amounts to strict proof of efficacy: the Panahi study lacks a placebo group, the placebo-controlled Patel study tested a multi-ingredient, product-specific formulation rather than isolated rosemary oil, and no study at all exists for the traditional homemade preparation – oil infusion or rosemary water. What it would take to turn "promising" into "proven" is a larger, placebo-controlled study on isolated rosemary oil, data on long-term use beyond six to twelve months, and a more precise clarification of the mechanism of action in humans. Until then, a homemade preparation remains a gentle, low-cost way to approach the traditional use – it is not a proven hair-growth remedy, and certainly not a substitute for medically assessed treatment of pronounced hair loss.