Does rosemary oil for hair growth actually work? Here's everything to know

If you’re on social media, chances are you’ve come across a video (or several) touting the efficacy of rosemary oil for hair growth. Said to thicken hair and lengthen strands, the hashtag #rosemaryhairgrowthoil has amassed over 500 million views (and counting) on TikTok.

But does it really work? While the ‘before and afters’ are certainly impressive, we want to know if this unlikely remedy can actually boost hair growth and help with hair loss – something that, according to the NHS, 8 million women experience in the UK.

To delve deeper, we’ve asked the experts to shed light on this wonder herb and whether we should be using rosemary oil for hair. Here's what they had to say…

What is rosemary oil?

Let’s begin with the basics. Rosemary is a herb native to the Mediterranean region. It’s oil, which is pale in colour and has a woody aroma, comes from the plant and is used for aromatherapy, in skincare products as well as haircare.

What are the benefits of rosemary oil for hair?

While the research is limited, there's some evidence to suggest that rosemary oil may help with hair growth. “Studies have demonstrated that rosemary oil can stimulate hair growth by improving blood circulation to the scalp and promoting the proliferation of hair follicle cells,” says Dr Nick Fisherman, Trichologist at Watermans Hair. “If hair follicles don’t get a sufficient blood supply, they will not get the nutrients they need to grow the hair.”

One 2015 study comparing rosemary oil to minoxidil (a popular hair regrowth treatment), found that after six months both groups had similar results with a significant increase in hair growth. “Although this study suggested it may be beneficial, there is currently a lack of clinical evidence to recommend rosemary oil as a hair loss treatment,” notes Zoë Passam, Consultant Trichologist at Philip Kingsley.

“The oil has also been found to possess anti-inflammatory properties, which can help soothe the scalp and reduce irritation and itching,” adds Fisherman. Essentially, rosemary oil can help create a healthy environment for optimum hair growth. Oh, and in the same study mentioned above, the group using rosemary oil reported less itchiness than those using minoxidil.

“Rosemary oil can also help to restore the scalp's microbiome balance due to its antimicrobial properties,” explains Dr Bhavjit Kaur, medical aesthetic practitioner. “Since dandruff usually occurs due to an excess of skin fungus (Malassezia), the antimicrobial properties of rosemary may help.”

How long does it take to see results?

The science suggests that it may work but as with anything there is a catch, rosemary oil needs to be applied in the right quantities, over a long period of time to see results. “There is limited evidence for rosemary oil as a hair loss treatment, but seeing results from any hair loss treatment takes time, due to the average rate of hair growth, typically 1-1.5cm per month,” says Passam. The experts agree that it takes six months (at least) to see results.

It's also important to note that hair growth can also be influenced by a variety of factors, including genetics, nutrition, stress, and hormonal changes, and the use of rosemary oil alone is unlikely to be the panacea for all hair growth.

How can I use rosemary oil for hair?

According to Fisherman, “when applying rosemary oil to your hair and scalp, it's important to dilute it with a carrier oil such as jojoba, coconut, or olive oil. This helps to prevent skin irritation and ensures that the oil is evenly distributed throughout your hair." Then leave the oil on your hair for at least 30 minutes before rinsing it off with shampoo and water. “Because rosemary oil can cause skin irritation, avoid using on inflamed or broken skin,” adds Passam.

After applying diluted rosemary oil, Hannah Gaboardi, Viviscal Ambassador and Trichologist, recommends using a scalp massager. "Scalp massaging increases hair thickness by stretching the cells of hair follicles. This then stimulates the follicles to produce thicker hair. So using it in conjunction with rosemary oil would be very effective".

Can you apply rosemary oil directly to your hair strands?

“Using rosemary oil directly on your hair strands can provide additional benefits such as improving hair texture, reducing split ends, and enhancing shine. To apply rosemary oil directly to your hair strands, you can add a few drops of the oil to your regular shampoo or conditioner, or create a hair mask by mixing the oil with a carrier oil and leaving it on for 20-30 minutes before rinsing. However, it's important to note that using too much rosemary oil directly on your hair can lead to dryness and irritation, so be sure to use it in moderation and dilute it properly with a carrier oil.” Fisherman warns.

Can rosemary oil help with hair loss caused by alopecia?

Alopecia is a medical condition that can cause hair loss that can affect any body part but there is no known cure for it yet. However, rosemary oil has been reported to help with hair loss caused by alopecia, but only anecdotally, since Rosemary oil stimulates hair follicles and improving circulation to the scalp. Fisherman believes that rosemary oil alone is not the cure for alopecia, and it may not be the most effective treatment. However he adds: “incorporating rosemary oil into your hair care routine may still have beneficial effects on hair health and growth, and it may be worth discussing with a healthcare provider or dermatologist as part of a comprehensive treatment plan.”

What are the side effects of using rosemary oil for hair?

Rosemary oil is known to have little-to-no side effects and is safe for all hair types, including coloured hair. “Like other essential oils, however, rosemary oil has active components and can result in scalp irritation,” flags Kaur. This is why it should always be diluted with a carrier oil. Also, it's a good idea to do a patch test - “if there is irritation, stop using it immediately.”