Is Rosemary Oil the Secret to Fuller, Longer Hair? Experts Break It Down

You’ve heard it repeatedly: what you consume is just as important as what you apply topically. Although the ingredients may differ (you wouldn’t eat hyaluronic acid), there are rare cases where components in our food can be just as beneficial for our hair, skin, and bodies as they are delicious. Rosemary is a notable example.

“Rosemary oil is a stimulating ingredient that promotes hair growth while stimulating blood flow, ultimately strengthening the hair follicle,” says Helen Reavey, a trichologist and founder of Act + Acre. The tingling sensation you feel on the scalp isn’t mere novelty—rosemary helps foster a clean, healthy canvas to boost blood circulation to the scalp and soothe dandruff and inflammation. Hair scalp massagers help encourage blood flow to the scalp, and there’s a rise in hair growth light therapy devices. But rosemary is a proven natural and effective way to thicken and strengthen hair.

Don’t just take our word for it. We turned to the experts for the facts on using rosemary oil for hair growth and learned there’s so much more to this essential oil than its great taste and scent. Keep reading to find out best practices, plus shop some of the best rosemary oil hair products—including top hair growth shampoos and scalp treatments—approved by experts.

Known its spicy, herby taste, rosemary oil is “a pale liquid from the rosemary plant, which has an herbaceous aroma,” says cosmetic chemist Ginger King. Cosmetically, it has a bevy of impressive benefits. “It’s often used in perfumes, skin care, and hair care as an antioxidant, anti-inflammatory, and antimicrobial ingredient,” King adds.

However, while it’s touted as one of the most effective ingredients in hair restoration, experts warn it should be used cautiously. “Rosemary extract/oil is extremely concentrated, so it’s generally recommended to dilute it with a carrier oil (such as argan oil or jojoba oil) before applying it directly to the hair and scalp,” says Reavey.

To maximize rosemary oil’s effects on hair, Reavey suggests coupling the ingredient with other powerhouses. “I also recommend products that contain peptides, stem cells, and ginseng to support hair health from the root and optimize the hair follicle’s function. Our Stem Cell Peptide Treatment contains clinically vetted Grape Stem Cells that create an environment for optimized hair follicle function, leading to thicker-looking hair in just 12 weeks,” she adds.

Improves hair growth: So, can rosemary oil really help with hair growth? Experts say yes. “The rosemary plant contains carnosic acid, which is known to heal nerve damage, tissue damage, and improve cellular turnover,” says Marnie Nussbaum, MD, FAAD, a board-certified dermatologist. “Therefore, it encourages nerve growth and improves blood circulation. The reason blood circulation is so important to hair growth is that without a proper blood supply, the follicles do not get the nutrients they need to grow the hair, and they can die off.”

“There is one study that compared [rosemary oil] specifically to [two percent] minoxidil (aka Rogaine off the shelf), and the finding is that the results appeared similar after six months,” says King. However, it’s important to note that minoxidil is also offered in a five percent strength, which is considered more effective. In another study performed on mice, the ingredient has also been shown to inhibit DHT, the male sex hormone that plays a major role in contributing to hair loss in both men and women. If you desire fuller, thicker, and more luscious strands, experts agree that rosemary oil is one of the most potent hair growth oils on the market.

“It smells amazing and is a personal favorite of mine,” says Dr. Nussbaum. “It is great for fine hair as it contains white vinegar as well which decreases product build-up that can cause stress on the follicle.”

This pre-wash oil soothes with tea tree and rosemary to stimulate the scalp, perfect for protective style takedowns or whenever your hair needs extra nourishment before shampooing.

Of course, water is necessary to hydrate your hair, but not everyone requires a daily wash day. In the interim days until your next wash, Camille Rose’s Rosemary Water boosts scalp stimulation via tingling rosemary to keep hair moisturized and less prone to breakage.

Made with rosemary, amla, and soothing aloe, this serum calms an irritated scalp, boosts overall shine, and stimulates hair growth.

Bergamy recommends this vegan-friendly shampoo with rosemary oil for hair growth. She says, “It works great for fine or thinning hair and is packed with vitamins and minerals that revitalize the hair shaft, plus gentle cleansers to help whisk away scalp build-up.”

Use this ultra-lightweight scalp and hair oil treatment before shampooing to boost your hair’s manageability and shine factor. “It combines rosemary oil and avocado oil to encourage hair growth while delivering moisture,” says Dr. Nussbaum.

Not only is this oil dermatologist-formulated (Dr. Camille Howard-Verovic is the founder), but the blend is a minty delight. Rosemary takes the lead to reduce hair thinning, as spearmint oil stimulates the scalp and pumpkin seed oil strengthens and adds shine.

Both Newman and Dr. Longsworth are fans of this product. “It’s great because it can be used as a scalp treatment to precisely deliver the hair follicle benefits,” says Newman. “The oil can be used as a leave-in/styler for natural, textured hair.”

The key ingredient rosemary leaf in this duo was formulated to create thicker-looking hair. Dr. Nussbaum notes it “encourages hair growth without sulfates, dyes, and parabens.”

Reduces scalp irritation: From that same minoxidil study, the majority of those who used rosemary oil also had less itchy scalps. “The rosemary plant in essential oil form is known to boast anti-inflammatory properties,” says Ope Ofodile, MD, MPH, a board-certified cosmetic and medical dermatologist at Dermatology and Surgery Specialists of North Atlanta. “This would be especially beneficial to help soothe distressed scalps.”

Can prevent hair loss: “Rosemary oil is a potent antioxidant that can fight against free radicals,” says Dr. Gaby Longsworth, Ph.D. scientist, certified hair practitioner, and owner of the blog Absolutely Everything Curly. These molecules destroy cells over time and can ultimately lead to hair loss by damaging the hair follicle.

Prevents dandruff: “In addition to improving blood circulation to the scalp, rosemary oil eliminates bacteria that clogs hair follicles,” explains Dr. Longworth. This can “potentially reduce the occurrence of flakes on the scalp,” adds King.

May help reduce gray hair: When cells are damaged from environmental aggressors, they can oxide, which research has shown can play a major role in accelerating aging processes, like hair graying. By actively fighting against those free radicals, rosemary oil may also be able to slow down the graying process.

Trichologist Penny James adds that rosemary oil’s aromatherapy benefits “can also be very helpful to reduce stress that’s known to cause graying.”

Reavey suggests leaving the oil in your hair for “at least 30 minutes,” and you can absolutely leave it in longer. “I recommend a good amount of time as it can be used as a leave-in treatment,” she says. Rosemary oil can be applied to the scalp and massaged in or even applied to the hair and covered with a shower or heating cap for a soothing treatment.

Although rosemary oil is not harmful, James warns against leaving it in hair overnight. “Leaving any kind of oil on the scalp for a prolonged period of time will upset the microflora of the scalp,” she says. “This can cause itchiness and redness, and it applies to all oils—not just rosemary oil.”

Not all hair will magically transform into Rapunzel-length strands upon using rosemary oil, as it depends on the person’s reaction to it. Also, be prepared to play the waiting game if longer hair is your goal. King says, “There is limited study to prove its effectiveness, but it takes more than six months [of use] to see results.”

“Rosemary essential oil can be used on any hair type because the benefits target the hair follicle, not the hair strand,” says hairstylist Matt Newman. “It is safe to use on color-treated hair, especially because its main use should be directly on the scalp.”

If you have sensitive skin and are unsure how your scalp skin may react, first talk to your dermatologist about integrating the oil into your routine. Newman recommends doing a small patch test first and waiting 24 hours to see if any irritation occurs. “Also, when applying to the scalp, tilt your head backward to avoid any oils dripping into your eyes.”

Also, “There is no data regarding use in pregnancy or breastfeeding; therefore, I would avoid it if possible,” advises Dr. Nussbaum.

Newman notes that rosemary essential oil differs from most carrier oils used in hair care because of its hair follicle health benefits. Hairstylist Cheryl Bergamy agrees, “Unlike other oils (like tea tree and peppermint), rosemary oil strengthens and promotes circulation for thirsty hair follicles that are starving of its blood supply and leading to hair loss.” One caveat: “It must be used more sparingly than carrier oils because overexposure can be irritating to the skin,” says Newman.

The physical weight of the oil could interfere with your style. Newman says that for people with thin or fine hair or a sparse density of hair, the oils can make the hair look greasy and weighed down. “If this is the case for you, try using the product as a pre-shampoo treatment reserved for days when you will be using a clarifying shampoo on your hair.”

“If you’re trying to suppress itching due to dandruff, use the oil mixed with compounds three to four times a week,” suggests James. “Massage it directly into the scalp, leave it on for 20 minutes, then shampoo the oils out of the hair and scalp.”

If you have very fine hair and/or an oily scalp, James advises using rosemary oil once a week as a scalp treatment and washing it out of hair immediately to avoid any greasiness.

Mix it with a carrier oil. “You can start by using rosemary essential oil one to two times per week and titrate use upwards to daily as tolerated,” says Dr. Nussbaum. “Only use five drops of it, add it to a carrier oil like coconut or jojoba oil and massage into the scalp for five to ten minutes, and rinse.” Diluting pure rosemary oil helps reduce potency and, therefore, decreases irritation on the skin.

According to James, rosemary oil can safely be combined with most other essential oils.

Blend into shampoo or conditioner. Bergamy suggests adding it to your shampoo or conditioner to get the benefits while washing your hair. Just be sure to thoroughly wash your hair to get the product out well.

Use rosemary oil products. Alternatively, instead of playing scientist and adding rosemary essential oil to other products, you can use ones that already include the ingredient.

Ginger King is a New Jersey-based cosmetic chemist.

Dr. Marnie B. Nussbaum is a board-certified dermatologist specializing in non-invasive aesthetic rejuvenation.

Dr. Ope Ofodile is a board-certified cosmetic and medical dermatologist at Dermatology and Surgery Specialists of North Atlanta.

Dr. Gaby Longsworth, Ph.D. scientist, certified hair practitioner, and owner of the blog Absolutely Everything Curly.

Penny James is a trichologist and founder of the Penny James Salon Trichology Center.

Helen Reavey is a trichologist and founder of Act + Acre.

Matt Newman is a hairstylist and social media star.

Sam Peters is a seasoned commerce writer and editor with over five years of experience covering beauty, fashion, and lifestyle topics. For this piece, she consulted dermatologists and hair experts about the benefits of rosemary oil.

Nerisha Penrose is the Beauty Commerce Editor at ELLE.com. Since joining ELLE.com in 2017, she has interviewed countless skin care professionals and has personally tested the latest and greatest products across makeup, skin care, and hair care.

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