The Honest Truth About Rosemary Oil & Hair Growth

Photographed by Hayleigh Longman
From thickening shampoos to retinol (yes, retinol), the topic of hair growth has been taking over TikTok for a while now, with countless solutions sitting under the hashtag. Rosemary oil is the one of the buzziest topics in the lineup of viral ingredients, and TikTokers are dubbing it a one-way ticket to growing your hair naturally.
Racking up over 2.8 billion views and counting, there's a good reason why the hashtag #rosemaryoil is trending: Like so many of the hyped up ingredients that came before it, a collective concern over hair loss (75% of British women say they're worried about hair loss, according to hair brand Philip Kingsley) is fueling the demand. And what's more appealing than a simple, natural remedy?
"Before and afters" show impressive hair growth results, but experts are warning that there's more to the story. So is rosemary oil the silver bullet solution for hair growth, after all? Or is it a herb that could do your hair more harm than good?
Here's what the experts think.
@thehealthyhur If you bought rosemary oil to regrow you hair but you have no idea what to do with it 🤷‍♀️, here's a step-by-step guide to get you started. ⬇ Dilute your rosemary oil with 5 drops of rosemary oil to 1 TBSP of a 'carrier oil' of choice. Heat it up in your hands and apply it directly to your scalp. If you want more tips and tricks on how to use rosemary oil for hair regrowth drop me a follow. ♥♥♥ #rosemaryoil #hairregrowthtips #hariregrowthjourney #hairregrowthtreatment #hairregrow #hairgrowthoil #healthyhair #hairtips ♬ original sound - Taylor Rose - Trichologist

What is rosemary oil? 

"Rosemary oil is the oil from the rosemary plant, also known as rosmarinus officinalis L.," explains Zoë Passam, consultant trichologist at Philip Kingsley. For years, the herb has been used to treat a host of ailments, for aromatherapy, skincare formulas and haircare.
"Rosemary has a long tradition of use as an important essential oil for a wide range of issues, most famously to improve memory and concentration, which goes back as far as ancient Greece," adds Alison Pawlus, principal scientist at Aveda.
It's "natural", too — perhaps one reason why the ears of TikTokers have pricked up. "There's growing interest in finding naturally derived solutions to help with hair growth, either to promote longer, healthier hair or in individuals with hair thinning," explains Pawlus. 

What are the benefits of rosemary oil for hair? 

Rosemary oil has a host of potential benefits. "It contains compounds which have been shown to have some anti-inflammatory, antimicrobial and antioxidant activities," explains Dr. Sharon Wong, consultant dermatologist and hair specialist. All such properties reduce scalp irritation, while antioxidants specifically help protect your hair from external aggressors such as pollution. Put simply, this tends to equal stronger strands and a healthier scalp.
"Rosemary oil can help with nourishment and locking in the hair's moisture and it has properties that improve blood circulation to the scalp, while getting rid of any bacteria that clog hair follicles," adds Hannah Gaboardi, leading trichologist and brand ambassador at Viviscal.
@kayli.boyle my hair has honestly felt like it’s growing in thicker #hairtok ♬ son original - ?

Is rosemary oil good for hair growth?

There has been some data that suggests rosemary oil could be good for hair growth, with two specific studies that point to its potential. "A study in 2015 compared the effects of rosemary oil versus 2% minoxidil [a topical medication] for the treatment of androgenetic alopecia [male and female pattern hair loss] and, after six months, found a similar increase in hair counts with both treatments," says Passam. Another study found that rosemary [essential] oil was an effective treatment for the patchy hair loss condition known as alopecia areata.
Though promising, these studies are small and the scientific research still preliminary. To add, the data is directed towards genetic hair loss (androgenetic alopecia) as opposed to analyzing specific types. Pawlus adds that rosemary oil has a number of beneficial compounds, but these studies speak exclusively of the essential oil, which is "the volatile, aromatic component of plants [what you smell], which excludes some of rosemary's powerful antioxidants."
The issue? The quality of the oil can vary. "It depends on many factors including the growth conditions of the plant, the quality of the plant collected and how it was handled prior to extraction," says Pawlus.

Is it safe to use rosemary oil on your hair and scalp?

The experts say that, in theory, people with all hair types can use rosemary oil but some may want to proceed with caution. "Although natural, as with all plant extracts and botanicals, rosemary oil extracts and the raw material itself can potentially cause skin irritation and allergic contact dermatitis in some people," explains Dr. Wong.
A possible catalyst for irritation is when using the oil alone. Despite what the TikTok videos might suggest, pure rosemary essential oil (and essential oils in general) is very potent and could cause scalp irritation. Worse yet, it might have the opposite of the intended effect. "Maintaining a healthy scalp plays a fundamental role in supporting healthy hair growth by providing conditions to optimize the function of the hair follicle," adds Dr. Wong. "There are many examples in which an unhealthy scalp can lead to increased hair loss such as eczema, psoriasis, fungal infections or yeast overgrowth."
To that end, if you are going to use rosemary oil, make sure you're diluting it with another oil-based product and massaging it into your scalp, says Gaboardi. "I recommend mixing four or five drops with a teaspoon of oil, like coconut oil. You can then massage it evenly into your scalp." It is also said that the massaging action might be the catalyst for stimulating hair growth. "Scalp massaging can help increase hair thickness by stretching the cells of hair follicles, which then stimulates the follicles to produce thicker hair," says Gaboardi. Never apply rosemary oil to inflamed or broken skin, adds Passam.
@kayli.boyle rosemary oil helps with growing in your hair thicker or if youre experiencing hairloss!🌿😍 #hairtok #hairloss #hairgrowth #rosemary ♬ Everywhere (2017 Remaster) - Fleetwood Mac

How do you use rosemary oil for hair growth? 

Aside from diluting it, not all rosemary oil formulas are created equal. Though sceptical about using rosemary oil as a hair growth treatment altogether, Passam suggests it's best applied as a leave-in product so that it has a greater chance of exerting its effects. "I would always recommend using rosemary oil in conjunction with other products [such as shampoos and serums] that support hair growth," adds Gaboardi, who says a balanced diet and supplementation are key.
Though plenty of new videos are surfacing to set the record straight, the misinformation that's being bandied about on TikTok is exactly what's causing concern among experts. Lack of education aside, many don't look at the root of the problem. "As a trichologist, my main concern would be that people may follow these trends when they would be better served finding out the reason for their hair loss and addressing this under the guidance of a specialist," says Passam. "Some types of hair loss are progressive so seeking appropriate advice early is likely to lead to better outcomes," she adds.
This isn't to say that rosemary oil doesn't have a place in your haircare routine, but more research is needed to understand whether it can really promote hair growth and density. For now, quality control and education is your best bet to determine whether you might want to try it out for yourself.
This article was originally published on Refinery29UK in February 2023 and has since been updated.

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