Rosemary Oil for Hair Growth: the Science Behind It and How to Use It

The internet is filled with products promising to promote hair growth these days, from scalp serums to biotin gummy supplements, each promoting instant results with very little investigation backing big claims. But hair growth oils have arguably garnered the most hype in recent years — more specifically, rosemary oil. It's racked up hundreds of millions of TikTok views, and scientific research supports its benefits.

All that said, it might not be for everyone, and there are some important things to keep in mind when adding rosemary oil to your haircare routine.

Here's what the research says about the benefits of rosemary oil for hair growth — plus some tips from board-certified dermatologists and trichologists on how to try it.

When you buy through our links, Business Insider may earn an affiliate commission. Learn more

While it may have only recently started trending on TikTok, rosemary oil has been used to treat hair loss for over 100 years.

Alongside the virality, a growing body of research highlights how effective it may be as a minoxidil alternative for hair growth.

The interest in rosemary oil for hair growth can be traced back to a 2015 study. In this particular study, participants with the common hair loss condition androgenetic alopecia were divided into two groups: one that used rosemary leaf oil and one that used minoxidil — also known as Rogaine — a prescription medication formulated to treat hair loss. When researchers followed up with these groups after three and six months, they found that participants who used rosemary oil experienced just as much hair growth as those who used the minoxidil. Not only that, but they also reported greater satisfaction with the treatment than the minoxidil users.

There's other research to support the hair growth benefits of rosemary oil, especially for people with alopecia — like this 2010 clinical review. A 2011 review also revealed that rosemary oil can actually be used as a preventive measure — warding off hair loss before it becomes a problem.

Much of the other research, however, has been conducted in animals.

A 2013 study in mice with hair loss triggered by testosterone showed that rosemary leaf extract stimulated hair growth. This suggests that it may be helpful for people assigned male at birth who are experiencing hormone-related patterned baldness.

Another 2022 study in rats found that rosemary oil is even more powerful for promoting hair growth than cedarwood oil, which is also believed to have benefits for the hair and scalp.

"Rosemary oil offers multiple benefits for hair health," says Meerika Khanna, a certified trichologist and founder of Rthvi.

Here's why experts believe rosemary oil works for hair growth.

Rosemary oil is rich in carnosic acid, a natural chemical that can boost circulation and even revive damaged nerves and tissue.

"This increased blood flow helps to nourish hair follicles, encouraging growth and leading to potentially thicker, healthier hair," explains Khanna.

"Rosemary oil can help fight off yeast, bacteria, fungus, and parasites living on the scalp — all of which can exacerbate most hair loss conditions," says William Gaunitz, a certified trichologist and founder of Advanced Trichology.

Poor scalp health — for example, as a result of dandruff — can negatively impact hair growth. Seborrheic dermatitis, a more extreme form of dandruff, is believed to develop as a result of an overgrowth of Malassezia — a particular type of fungi that lives on the skin of humans. A 2017 study found that rosemary oil can kill some bacteria and fungi — which, according to Khanna, can contribute to an overall healthier scalp.

In the 2015 study comparing the hair growth benefits of minoxidil and rosemary oil, participants who used the rosemary oil experienced significantly less scalp itching than those who used the minoxidil.

Rosemary oil also has anti-inflammatory properties. This is another noteworthy benefit, given that inflammation is linked to a number of scalp disorders that can affect hair growth — including psoriasis, atopic dermatitis, and seborrheic dermatitis.

"By reducing inflammation, rosemary oil improves the function of the hair follicle and allows for thicker, stronger growth," says Gaunitz.

A 2021 study found that when people with thinning hair applied leave-in scalp treatments with antioxidants for 24 weeks, they experienced less hair shedding and improved scalp health. They also had a higher total hair count by the end of the study. Fortunately, rosemary oil is packed with antioxidants.

"Rosemary oil's antioxidant effects could also help protect the hair from damage," says Dr. Shoshana Marmon, MD, a board-certified dermatologist and assistant professor of dermatology at New York Medical College.

There's a difference between growing thicker, longer locks and recovering from hair loss. If you've experienced hair loss, experts agree that the best course of action is to talk with your doctor or dermatologist about the best treatment options for you.

Addressing the root cause of your hair loss — whether it's a scalp infection, hormonal imbalance, stress, or thyroid problem — is a crucial first step on your hair growth journey. For example, if your hair loss stems from a deficiency in iron, protein, or zinc, all the rosemary oil in the world probably won't completely solve your issue — you'll also need to up your intake of these nutrients.

Once you've taken this step, adding rosemary oil may help to complement other treatments your doctor or dermatologist recommends. In fact, the 2015 study found that the people who used rosemary oil experienced a much greater reduction in hair loss than the minoxidil group.

On the other hand, if you aren't experiencing hair loss or scalp health issues, rosemary oil alone could help to complement your hair growth efforts.

There are several different ways to use rosemary oil for hair growth.

Boakye recommends mixing a few drops with a carrier oil, massaging it directly into your scalp, and leaving it on for at least 30 minutes — before washing it out. You can also add it to your favorite shampoo for hair growth or conditioner.

Like all essential oils, rosemary oil is super concentrated — so applying it straight to your scalp could irritate your skin, says Marmon. To reap the benefits without these risks, Khanna and Marmon advise always diluting it with a carrier oil.

According to Khanna and Marmon, some of the best carrier oils for rosemary oil include:

You can also use olive oil, sweet almond oil, and avocado oil.

Khanna recommends aiming for 2% rosemary oil when diluting it.

This equates to about 2 drops of rosemary oil per teaspoon of carrier oil.

Or, if you're adding the rosemary oil to an 8-ounce bottle of shampoo or conditioner, you'd add about 80 drops of rosemary oil.

For best results, Marmon, Khanna, and Boakye advise using rosemary oil two to three times per week.

"This frequency is dependent on personal preference and tolerance," adds Marmon.

According to Khanna, leaving it on overnight can enhance its effectiveness — allowing the scalp plenty of time to absorb the rosemary oil's beneficial compounds.

You can purchase logo and accolade licensing to this story here.Disclosure: Written and researched by the Insider Reviews team. We highlight products and services you might find interesting. If you buy them, we may get a small share of the revenue from the sale from our partners. We may receive products free of charge from manufacturers to test. This does not drive our decision as to whether or not a product is featured or recommended. We operate independently from our advertising team. We welcome your feedback. Email us at [email protected].