There have been a few studies investigating the potential benefits of using rosemary oil for hair growth and hair loss prevention, but the evidence is limited and more research is needed to fully understand its effects.
One study published in 2015 in the journal Skinmed found that a 2% solution of topical rosemary oil was effective in improving hair thickness and hair growth in people with androgenetic alopecia (a common form of hair loss). The study included 50 participants who applied the rosemary oil solution to their scalp twice daily for six months, and the results showed significant improvements in hair growth compared to a control group.
Another study published in 2013 in the International Journal of Pharma and Bio Sciences found that rosemary oil had a positive effect on hair growth in mice. The study included four groups of mice, each of which received a different treatment for 21 days: a control group, a group treated with minoxidil (a common hair loss treatment), a group treated with a 3% solution of rosemary oil, and a group treated with a combination of minoxidil and rosemary oil. The results showed that the mice treated with rosemary oil and the combination treatment had greater hair growth compared to the control group and the minoxidil group.
While these studies suggest that rosemary oil may have some benefits for hair growth and hair loss prevention, more research is needed to confirm these effects and to determine the optimal dosage and application method. It is also important to note that some people may be allergic or sensitive to rosemary oil, so it is recommended to do a patch test before applying it to the scalp. Additionally, it is always a good idea to talk to a healthcare provider or dermatologist before starting any new hair care regimen or treatment.