So, there’s been a lot of fuss on social media over the last few months about rosemary oil being a wonder treatment for hair growth. Of course, a lot of these social media fads are complete nonsense, which led us to the question. Does rosemary oil grow hair? And if so, how does it actually do that.
The science is a little shallow on this on, the odds are that the answer is, yes it seems to help. At least in terms of increasing the number of growing hair follicles, but the most cited study is often a little misquoted in marketing. Especially when it comes to how quickly it works.
Then of course there is a lot of anecdotal evidence in it’s favor, but, we’re not going to get too much into that, we’re sure you can find plenty of pro rosemary oil success stories yourselves.
There is also the question of what percentage of people it actually works for as well. And this is where it get’s a little more questionable. Not bad, just not as great as many people would have you believe.
The Rosemary Oil Studies
You’ll often see the 2015 study that compared rosemary oil vs minoxidil, a medication used for hair loss. And a lot of people say it was shown to be as effective, but natural and cheaper. And it’s often quoted as being effective within 3-6 months of use. But, what the study showed was that neither were effective within 3 months at all, but that at 6 months there was in fact a significant increase in hair count. So, whilst this is technically true, you’re probably going to need to stick to using it for 6 months if you want it to be effective. 
This study was also conducted on people with alopecia, so that doesn’t necessarily mean it’s going to do anything for people who are not suffering with thinning hair. It doesn’t mean it won’t either. But, it’s worth noting.
Lastly it’s worth noting that minoxidil is usually only effective for around 30% of patients  so these stats were suggesting rosemary matched up on this front as well. And this will be further backed up shortly.
More Studies: But Not Just on Rosemary oil
Now, there are two other well document studies on tonics containing rosemary oil, but these were of mixtures with other oils. One was Thyme, Rosemary, Lavendar and Cedar oil, the other was the same but with Primrose Oil as well.
It should be noted that it didn’t work for everyone. The trial with less ingredients showed 70% of people responded with significantly increased follicle growth, vs 40% in the placebo. And the other showed 45% vs 15% in the placebo. [3,4]
Meaning we can assume that Rosemary has a 30% efficacy rate above that of a placebo. Which oddly lines up with what we discussed from the Rosemary oil vs Minoxidil study. That doesn’t necessarily mean that it’s 30% effective in general, but it’s also not an unreasonable assumption given the information we have.
How Does Rosemary Oil Work?
The effectiveness of rosemary oil for hair growth can be attributed to its key component, carnosic acid. Carnosic acid possesses anti-inflammatory and antioxidant properties, which can help rejuvenate damaged nerves and tissues and create an environment conducive to hair growth.
What Else Does Rosemary Oil Do For Hair?
One notable advantage is its ability to control dandruff. Rosemary oil's anti-inflammatory properties help reduce scalp inflammation and irritation, which are often associated with dandruff, or seborrheic dermatitis.
There is also some, albeit relatively limited, evidence to suggest that rosemary oil may help limit premature graying of hair.
Conclusion: Does Rosemary Oil Grow Hair?
There’s definitely some evidence to suggest that Rosemary oil could well be as effective as other commercially available hair growth treatments. And it working for 30% of people definitely isn’t a bad success rate. Depending on how you look at the trial results. Considering rosemary comes with a relatively cheap price point, there isn’t really too much to lose. But of course make sure to mix it with a carrier oil and get the percentages right so as not to cause scalp irritation and have the opposite effect.
We generally recommend using a brand that sends packages of rosemary oil with carrier oils to avoid any problems like Toxique Girl, although there aren't many that are of overly high quality unfortunately..
1 - https://pubmed.ncbi.nlm.nih.gov/25842469/
2 - https://www.sciencedirect.com/topics/chemistry/minoxidil
2 - https://pubmed.ncbi.nlm.nih.gov/9828867/
3 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595365/