Is Rosemary Oil a Real Treatment or Just a Supplement?

In recent years, rosemary oil has gained popularity as a natural remedy for hair loss and other hair-related issues. Influencers and natural product brands promote it as an effective alternative to pharmaceutical treatments, claiming that it stimulates hair growth and strengthens follicles.

However, the key question is: Is it truly a science-backed treatment or just a supplement with limited benefits? To answer this, we will review clinical studies and scientific evidence that support (or refute) its effectiveness.

How Does Rosemary Oil Work on Hair?

Rosemary essential oil (Rosmarinus officinalis) is rich in bioactive compounds such as eucalyptol, camphor, and phenolic acids, which have been studied for their antioxidant and anti-inflammatory properties. When this oil comes into contact with the scalp, its components can penetrate the skin and act at different levels. It has been proposed that rosemary stimulates microcirculation in the area, which could increase blood flow to hair follicles. No study has measured this in people’s scalps.

Additionally, a mouse and test-tube study found that rosemary leaf extract inhibited 5-alpha reductase, the enzyme that converts testosterone into dihydrotestosterone (DHT), the primary hormone implicated in androgenetic alopecia (Murata et al. 2013). Whether rosemary lowers DHT in the human scalp has not been shown.

It is also attributed with antimicrobial properties, which could help maintain a healthier scalp environment, free of infections that can weaken follicles.

But what does the science say about it?

Scientific Evidence: Real Support or Limited Studies?

2015 Study: Rosemary Oil vs. Minoxidil

One of the most cited studies on rosemary oil and its potential effect on hair growth was published in Skinmed in 2015. This study was designed to directly compare the effectiveness of rosemary oil with 2% minoxidil, an FDA-approved drug for treating androgenetic alopecia.

Panahi and colleagues (Skinmed, 2015; PMID 25842469) randomised 100 people with androgenetic alopecia to rosemary oil or 2% minoxidil for six months. Neither group’s hair count changed significantly at three months; both rose significantly from baseline at six months, with no significant difference between the groups. Scalp itching increased in both groups and was more frequent with minoxidil. There was no placebo arm, the comparator was the weaker 2% strength, and the trial has not been independently replicated, so it cannot show that rosemary oil is as effective as minoxidil.

The study has other limitations. The sample of 100 participants is relatively small to establish definitive conclusions. The study duration was only six months, which does not allow for evaluating the long-term effects of rosemary oil. It is also relevant to note that the minoxidil concentration used was 2%, while the most commonly used and recommended concentration for treating androgenetic alopecia in men is 5%.

Mouse and laboratory study (2013)

Rosemary leaf extract improved hair regrowth in mice given testosterone and inhibited 5-alpha-reductase in the test tube (Murata et al., Phytother Res 2013, PMID 22517595). The extract and one of its compounds also reduced the growth of androgen-dependent cells in the lab.

The research was conducted on mice and cells, and effects observed in animal models do not always carry over to humans. The study used a leaf extract, not rosemary essential oil.

The study is a starting point for future research. Rigorous clinical trials in humans are needed before considering rosemary a reliable treatment for hair loss.

Why Is It Important to Differentiate Between a Treatment and a Supplement?

When looking for a solution to hair loss, it is crucial to distinguish between a treatment and a supplement. A treatment is a product or substance with scientific evidence supporting its effectiveness in directly addressing a specific condition, such as minoxidil, which is FDA-approved for hair growth. In contrast, a supplement is a product that may provide indirect benefits by improving overall hair health but lacks conclusive proof that it can reverse alopecia on its own.

Differentiating these concepts is essential because many people start using natural products expecting results similar to clinically approved drugs. However, a supplement can be a useful addition to a hair care routine but should not replace a clinical treatment if an effective, proven solution is sought.

User Experiences

Community feedback on rosemary oil as a hair loss treatment is mixed, with some users reporting positive effects while others remain skeptical.

Many users compare rosemary oil to minoxidil, citing the 2015 study as showing rosemary oil was as effective as 2% minoxidil in treating androgenetic alopecia; as noted above, the trial found no significant difference but had no placebo arm and cannot show the two are equally effective. However, several users pointed out that the study had limitations, including a small sample size and a relatively short duration. Some users noted that while rosemary oil may improve scalp circulation and reduce inflammation, it is unlikely to be as potent as minoxidil or finasteride in promoting regrowth.

A number of users shared their personal experiences using rosemary oil, with some reporting that it helped slow shedding and improved hair thickness over time. One user mentioned that after consistent use for several months, their hair felt healthier, but they did not see significant regrowth in bald areas. Another user emphasized that results varied depending on the individual and that rosemary oil might work best as a supplementary treatment rather than a primary solution.

On the other hand, some users were skeptical about rosemary oil’s effectiveness, stating that while it has anti-inflammatory and antimicrobial properties, it lacks the strong scientific backing of FDA-approved treatments like finasteride and minoxidil. A few users reported experiencing scalp irritation or increased shedding when using rosemary oil, though this was relatively uncommon. Others argued that any benefits seen were likely due to the massaging action during application rather than the oil itself.

Overall, community feedback suggests that rosemary oil is generally considered more of a supplement rather than a standalone treatment. Some users have incorporated it into their hair care routines alongside proven treatments like minoxidil or microneedling, but it is not widely viewed as a primary solution for significant hair regrowth. Many community members advised keeping expectations modest.

So, Is Rosemary Oil a Treatment or a Supplement?

Rosemary oil is available on the market in two main forms: as a topical treatment and as an oral supplement.

In its topical form, it is found in products such as hair serums, shampoos, and essential oils applied directly to the scalp.

On the other hand, rosemary is also sold in capsule or liquid extract form for oral consumption, based on the premise that its antioxidant and anti-inflammatory properties can improve hair health from within. However, its direct impact on hair loss has not been sufficiently studied. Anyone considering a rosemary supplement should ask a pharmacist or doctor first, especially if pregnant, breastfeeding or taking other medicines.

Despite these different forms, scientific studies have primarily evaluated rosemary oil’s effectiveness in topical applications. The one human trial tested rosemary oil applied to the scalp, and it had no placebo arm. There are no clinical trials of oral rosemary for hair loss.

Safety. Rosemary essential oil is concentrated. Poison Control advises diluting essential oils in a carrier oil before they touch the skin, not using them on damaged skin, and stopping if a rash appears (National Capital Poison Center). Allergic contact dermatitis to rosemary has been reported (Serra et al. 2005). Rosemary oil is not for swallowing: some essential oils are poisonous if swallowed, and children are more susceptible, so keep bottles out of their reach (National Capital Poison Center). The EU herbal medicines committee does not recommend rosemary oil products for people under 18 or during pregnancy or breastfeeding, because safety has not been established, and advises keeping it away from the eyes (EMA, 2024).

In that sense, rosemary oil is more accurately categorized as a supplement or complement in a hair care routine rather than a medically proven treatment.

In summary...

Rosemary oil has one small human trial, against the weaker 2% minoxidil and with no placebo arm, plus mouse and laboratory studies. The research is scarce and methodologically limited. It is not a replacement for medically approved treatments for alopecia.

References

Panahi, Y., Taghizadeh, M., Marzony, E. T., & Sahebkar, A. (2015). Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: A randomized comparative trial. Skinmed, 13(1), 15-21. Retrieved from https://pubmed.ncbi.nlm.nih.gov/25842469/

Murata, K., Noguchi, K., Kondo, M., Onishi, M., Watanabe, N., Okamura, K., & Matsuda, H. (2013). Promotion of hair growth by Rosmarinus officinalis leaf extract. Phytotherapy Research, 27(2), 212-217. https://doi.org/10.1002/ptr.4712. Retrieved from https://pubmed.ncbi.nlm.nih.gov/22517595/

Serra, E., Vila, A., Peramiquel, L., Dalmau, J., Granel, C., & Alomar, A. (2005). Allergic contact dermatitis due to rosemary. Contact Dermatitis, 53(3), 179-180. Retrieved from https://pubmed.ncbi.nlm.nih.gov/16128769/

European Medicines Agency, Committee on Herbal Medicinal Products (2024). European Union herbal monograph on Rosmarinus officinalis L., aetheroleum (EMA/HMPC/513893/2021, Revision 1). Retrieved from https://www.ema.europa.eu/en/medicines/herbal/rosmarini-aetheroleum

National Capital Poison Center. Essential oils: Poisonous when misused. Retrieved from https://www.poison.org/articles/essential-oils