Does Rosemary Improve Scalp Circulation, and Would That Regrow Hair?

Rosemary, an aromatic herb commonly used in cooking, has gained attention in the field of hair health. It is attributed with properties that improve blood circulation, but the question arises: can it really regenerate hair? To answer this, it is first necessary to understand what circulation and hair regeneration mean from a scientific perspective.

What Is Blood Circulation and What Circulates in the Body?

Blood circulation is the process by which blood is transported through the cardiovascular system, driven by the heart, along arteries, veins, and capillaries. Its primary function is to deliver oxygen and essential nutrients to all organs and tissues of the body while simultaneously removing metabolic waste products.

Blood flow is essential for maintaining cellular health and tissue function, including the scalp. Without adequate circulation, hair follicles can suffer from nutritional deficiencies that impact their ability to produce strong and healthy hair.

Why Is Circulation Important for Hair Growth?

Each hair follicle is connected to a network of blood vessels that supply it with oxygen and key nutrients, such as iron, zinc, biotin, and essential proteins. Poor blood flow can lead to reduced nutrient supply to the follicles, resulting in weakened hair, thinning, and, in some cases, premature shedding.

Certain compounds and practices are believed to enhance microcirculation in the scalp. Rosemary has been promoted as a natural vasodilator, a substance that widens blood vessels so more blood reaches the hair roots. This has not been measured in the human scalp. However, improving circulation is only one part of the process: hair growth also depends on hormonal, genetic, and nutritional factors.

What Does Hair Regeneration Mean?

Human hair undergoes a growth cycle composed of three main phases:

• Anagen phase: This is the active growth phase of hair, lasting between two and six years.
• Catagen phase: A transitional phase in which hair growth stops and the follicle begins to shrink.
• Telogen phase: The resting phase, during which old hair sheds to make way for a new growth cycle.

Hair regeneration occurs when a follicle in the telogen or inactive phase re-enters the anagen phase and starts producing new hair. However, in cases of advanced alopecia, follicles can atrophy, preventing natural regeneration. In these scenarios, science seeks effective solutions to stimulate the reactivation of dormant follicles.

Hair Regeneration in Marketing vs. Science

In the cosmetic industry, hair regeneration is a term frequently used in the marketing of shampoos, tonics, and treatments. It is common to find products that promise to "regenerate" damaged hair, stimulate its growth, or reverse hair loss.

However, in the scientific field, regenerating hair involves a complex biological process in which a miniaturized or inactive hair follicle re-enters the anagen phase and begins producing new hair. Regeneration does not simply mean strengthening or thickening existing hair but rather the reactivation of dormant follicles.

Marketing claims often rely on active ingredients that may improve scalp health or strengthen the hair shaft, but this does not equate to hair regeneration in scientific terms. Rosemary is a prime example of this. Many hair products containing rosemary extracts claim to stimulate hair growth based on its ability to enhance blood circulation in the scalp. However, for a compound to be considered an effective solution for hair regeneration, it must have solid clinical studies supporting its efficacy.

What Does Science Say About Rosemary and Hair Regeneration?

Various studies have analyzed the effects of rosemary on hair health, evaluating its potential impact on scalp microcirculation and follicle activity. While some research suggests that rosemary may support hair growth, it is crucial to examine the methodology and findings in detail.

A 2015 clinical trial compared the effectiveness of rosemary oil with 2% minoxidil in 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. It also did not measure scalp circulation or show a regenerative effect on hair follicles.

Murata and colleagues found that rosemary leaf extract improved hair regrowth in mice given testosterone and inhibited 5-alpha-reductase in the test tube; they did not measure blood flow (Phytother Res 2013, PMID 22517595, DOI 10.1002/ptr.4712).

However, results in animal models do not always directly translate to humans, necessitating further research in human populations.

In 2023,  a study in mice found a 1% rosemary-extract lotion promoted more hair growth than 2% minoxidil in those mice (Begum et al., PMID 37200757). Mouse results often do not carry over to people. However, the lack of clinical trials in humans limits its applicability, preventing definitive claims about rosemary's ability to regenerate hair.

Hair regeneration remains a complex process that cannot be attributed to a single ingredient. More human-based research is needed to determine whether rosemary can be considered an effective and scientifically validated treatment for hair loss.

User Experiences

Rosemary oil is often promoted for its potential to improve scalp circulation, but community feedback on its effectiveness for hair regrowth is mixed. Many users have experimented with rosemary oil as a natural remedy, with varying results. Some report noticeable improvements in hair thickness and reduced shedding, while others see little to no change.

One user noted that after three months of consistent application, they experienced less shedding and some fine hair regrowth, particularly in thinning areas. They credited rosemary oil’s potential anti-inflammatory and circulation-boosting effects but emphasized that their results were subtle compared to proven treatments like minoxidil. Another user echoed this sentiment, stating that while rosemary oil made their scalp feel healthier and less irritated, they did not observe significant new hair growth.

**Some users attempted to compare rosemary oil to minoxidil, referencing the 2015 study as suggesting rosemary oil might be similarly effective over six months; that trial found no significant difference but had no placebo arm and cannot show equal effectiveness. **However, many community members remained skeptical, highlighting that anecdotal experiences do not always align with clinical outcomes. One comment stressed that rosemary oil alone is unlikely to reverse genetic hair loss (androgenic alopecia) but could be a supportive treatment alongside DHT blockers like finasteride.

Others were more critical, dismissing rosemary oil as ineffective based on their own trials. One frustrated user mentioned using it daily for nearly a year with no visible regrowth, questioning whether the claims surrounding rosemary were exaggerated by social media trends. Several users agreed, emphasizing that while rosemary oil might improve scalp health, it does not match the proven efficacy of pharmaceutical treatments.

Overall, the consensus among users is that rosemary oil may offer some benefits for scalp health and circulation, but its ability to regenerate hair remains questionable. While some individuals see mild improvements, most users agree that it is not a substitute for FDA-approved treatments like minoxidil and finasteride.

Final Considerations

No study has measured whether rosemary improves scalp blood flow in people, and its ability to regenerate hair in scientific terms remains unproven. The only human trial was small and had no placebo arm; the other studies were in mice or the lab. More high-quality clinical trials are required to determine whether rosemary can be considered an effective treatment 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).

References

Panahi, Y., et al. (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., et al. (2013). "Promotion of hair growth by Rosmarinus officinalis leaf extract." Phytotherapy Research, 27(2), 212-217. Retrieved from https://doi.org/10.1002/ptr.4712

Begum, A., S, S., N, A. K., & Ali, S. S. (2023). "Evaluation of Herbal Hair Lotion loaded with Rosemary for Possible Hair Growth in C57BL/6 Mice." Advanced Biomedical Research, 12, 60. Retrieved from https://pubmed.ncbi.nlm.nih.gov/37200757/

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

It is advisable to consult a healthcare professional before starting any hair loss treatment, even when using natural remedies such as rosemary.