The Science Behind Rosemary Oil Is Shaky, So Why Are We Slathering It All Over Our Scalps?

Spend enough time on social media and one thing becomes apparent: rosemary oil, either homemade or store-bought, is being slathered onto scalps the world round. Unassuming bottles – often made by the brand Mielle or Nature Spell but, on occasion, homemade – are held up to the camera and praised for improved hair density, growth and scalp health. There is nothing, it seems, the wonder oil cannot do. On TikTok, videos tagged as including rosemary oil for hair growth number into the hundreds of millions. One video, posted by creator Fleur Green shows her hair six months into hair oiling and has over 10 million views. In the comment section, questions abound: how best to use rosemary oil, when to apply it and if they can expect the same results.

Unfortunately, the science isn’t as certain. While popular in anecdotal accounts, like the videos and images posted on TikTok and Instagram, hard evidence is limited. Zealots will say I’m discounting the (much quoted) study that says rosemary oil is as effective as the popular hair loss chemical minoxidil over six months. But, and this is crucial, that study only canvassed 100 men and didn’t include follow-up findings after the six months had finished. It’s not nothing but it’s also not as groundbreaking as, perhaps, people have claimed.

So, what’s the rub when it comes to hair loss: are there treatments that can reverse the speed and severity of hair loss? I asked the experts: trichologists Jane Mayhead and Eva Proudman and hair transplant surgeon Mr Christopher D’Souza to break it down. 

Hair loss occurs for several reasons: genetics, iron, thyroid and hormonal imbalances, nutritional deficiencies, stress, medical conditions, certain medications, post-partum changes and even the way you style your hair. But, that doesn’t mean the strands caught in your hairbrush are always a cause for concern. A healthy scalp loses between 50 and 100 hairs per day (likely more than we realise) and some hair loss is completely normal. However, hair loss that exceeds this is something to look into. Here, we break down the common causes of hair loss.

“The most common cause of hair loss in women is androgenetic alopecia (female pattern hair loss),” hair transplant surgeon and owner of The D’Souza Clinic, Mr D’Souza, explains. “While the exact pathogenesis (why a disorder develops)  is still not fully understood, we do know that genetic, hormonal and environmental factors all play a part.” 

He goes on to describe that up to 20 percent of women suffer from low iron and that thyroid conditions, which can both affect hair growth, often slip under the radar and go undiagnosed. If you suspect this might be the case, a blood test by a GP or an at-home service like Medichecks can confirm any suspected deficiencies. 

Finally, dietary deficiencies – specifically iron, zinc and vitamin D – can result in expedited hair shedding. Mr D’Souza says that while we should be trying to get as many of our vitamins and minerals from our food (eggs, red meat, shellfish and dark leafy greens are particularly beneficial), supplementation can help where necessary. (I take the Zooki Liposomal Iron Bis-Glycinate each morning, a liquid iron supplement as it has vitamin C included in it to maximise absorption. Pure Encapsulations, Wild Nutrition and JS Health also sell popular iron supplements.)

We know stress isn’t good. It’s the culprit for many a problem: sleep disturbances, high blood pressure, poor digestion and blood sugar, to name a select few. So, it’s unsurprising then, that it can also play a role in hair loss. And it isn’t just the type of stress that has you cursing your boss or muttering in traffic, it’s stress in all its forms: illness, crash dieting and calorie restriction, childbirth and major life events, for example. However, hair loss caused by stress isn’t necessarily permanent, Mr D’Souza says. 

“Stress-induced hair loss is temporary and usually noticed a few months after the cause.” He notes that while the hair loss can be quite dramatic, in the majority of cases the hair will come back. “This usually happens three to four months after the stressor has passed.”

Traction Alopecia and Manual Damage

Put down the brush and step away from the slicked-back bun. Tying your hair in tight, unrelenting styles like ponytails, braids or extensions can put so much pressure on the hair (specifically the hairline) that the follicle is damaged, scarred and new hair will cease to grow. For bedtime, the best practice is to find a silk or satin scrunchie and loosely tie the hair on the top of your head. Any lower and you risk rubbing it on the pillowcase as you move in your sleep or transferring the heat from your body (around 37°C/98.6°F) to your hair all night.

Lastly, hair loss can be caused by underlying conditions like alopecia (of which there are many types). Mr D’Souza recognises that these are difficult to diagnose and often require a biopsy. This is why reaching out to a professional is crucial.

Before you reach for the rosemary oil or press pay on a red light helmet, let’s look at what the science says.

Unfortunately, you already know where I’m going with this one. The science just isn’t there yet to back up what the converts on TikTok are shouting from the rooftops. “Rosemary is a good ingredient when included in formulations such as shampoo,” says Eva Proudman, a consultant trichologist for Absolute Collagen “And, while it will help with irritated scalps, it won’t make the hair grow longer or quicker.”

Similarly, Jane Mayhead, a trichologist at The Private Clinic on Harley Street, recommends viewing any rosemary oil being touted as a miracle worker with caution. “Texturally, natural remedies like oil may help to improve the but there is no robust research into the benefits of rosemary oil and, crucially, not all oils are the same in quality.”

If you’ve used rosemary oil and found it works for you, by all means, don’t let me be the one to stop you. But, if you’re on the fence or feeling woeful after an unsuccessful bout of scalp oiling, know that you’re not alone.

(A word to the wise: if you are currently using rosemary oil, check to see if it needs to be diluted before applying it to your scalp. If it does need to be diluted, using it without water or a carrier oil could cause irritation and damage to the scalp.)

Not only does it feel good but scalp massage is purportedly meant to help stimulate healthy hair growth. Again, while the science is shaky, anecdotal accounts have said that regular scalp massage has observably increased hair density. 

“Scalp massage can help to improve scalp health and increase blood flow,” says Mayhead. “But, scalp massage alone will not prevent hair thinning or loss.” 

This is where it gets tricky. On the one hand, people online are waxing lyrical about scalp massage, with creators like @haircareking sharing tutorials on TikTok describing how to massage specifically for hair growth. One video, viewed over 750k times, has him telling viewers to take the pads of their fingers and press down into the scalp, moving the skin in small circles. He goes on to say that tipping his head upside down helps to increase blood flow. Another video, by @zadehbeauty, says moving the scalp over the skull with your palms is the key to hair growth. While both creators aren’t wrong – scalp massage will increase blood flow to the skin’s surface – there isn’t quite enough evidence to say this will be adequate to increase hair growth. 

Don’t think I’m above a good scalp massage, though. Using a silicone scalp massager – this Hello Klean one, to be precise – has transformed my hair wash days. Not only does it feel heavenly, but the bristles mean my shampoo is properly lathered and my scalp efficiently exfoliated; two things that are much harder using fingertips only. 

Finally, some good news. Light therapy – low-level laser, specifically – has enough research behind it that Mayhead, Proudman and D’Souza all recommend it when I ask. 

“For red light therapy to be effective for hair loss it needs to be a low-level laser that is used,” Proudman explains, going on to say that infrared light doesn’t treat conditions like androgenetic alopecia (female pattern hair loss). “This is due to the depth and penetration of the light source, something the research tells us needs to be low-level laser light.”

Ideally, Proudman advises, laser therapy for hair loss would happen over two to three twenty-minute sessions a week, recommending the Theradome Pro80 laser helmet she uses in her clinics. If visiting a trichologist for laser therapy isn’t viable, there are at-home devices that contain similar technology. 

Current Body, the skin technology brand with a cult and celebrity following for its LED mask, sells what they call the Hair Growth Helmet, £650. It comes in two sizes (small/medium and medium/large) and uses low-level light therapy to stimulate the scalp and improve hair loss. Be warned, you will look like an amateur astronaut while wearing it but, for the potential benefits, it’s a small price to pay. Hairmax, another cosmetic technology brand, sells a hairband-shaped device – the Laserband 82 Comfort Flex, £850 – that’s designed to be used over the entire scalp, simply moved into three different positions to cover the entirety of the head. 

Both options are expensive. Much more so than the £8 rosemary oil sells for online. And, what works for one might not be quite right for another. The most important thing, if you are really struggling with chronic or unexpected hair loss, is to speak to a professional – whether that be a trichologist, dermatologist or hair transplant surgeon. They will be able to help ascertain exactly why your hair is thinning, if more tests are needed and the way to approach mitigating or reversing it. Remember, you and your scalp are entirely individual: what works for one person on TikTok or Instagram might not work for another. And, as with everything fed to us through our phone screens, take what works for you and leave the rest.

Tweaking our routines, diet and supplementation can play a part in addressing some types of hair loss. Others, though, require professional diagnosis and protocols. Proudman sets out the signs to look out for: 

If you…

• notice more hair shedding when you wash and brush,
• feel you can see more scalp,
• notice the scalp looks pink, itches or burns, 
• notice scales or flakes, patchy loss or hairline recession 

“These are all reasons to seek professional help,” she advises. “The sooner you do so the sooner an accurate diagnosis can be made, and in some cases the more hair we have to work with the better the outcome from treatment and management.”