Rosemary Hair Oil and the Study Behind the Trend

Most of the rosemary hair oil on your feed traces back to one paper. In 2015 the journal Skinmed published a trial that assigned 100 people with androgenetic alopecia to rosemary oil or minoxidil 2% for six months. Neither group showed a significant change at three months. At six months both groups had a significant increase in hair count, with no significant difference between them, and scalp itching was more frequent with minoxidil. It is one study, and I read it as a reason to try rosemary with patience, not a promise.

Mielle Rosemary Mint Scalp and Hair Strengthening Oil is the bottle that made the idea mainstream. It launched in 2018 and later went viral on TikTok. Founder Monique Rodriguez was a registered nurse who partnered with a chemist in 2014 on her first product and named the brand after her daughters, Mia and Arielle. The oil blends biotin, mint and essential oils. Briogeo Scalp Revival Rosemary Pre-Wash Oil comes from Nancy Twine, who launched Briogeo in 2013 while still working in finance, inspired by her grandmother's homemade remedies.

The others take slightly different routes. Kitsch Rosemary Scalp and Hair Oil is a plant-based pre-wash with biotin, castor and jojoba oils, Sky Organics Organic Rosemary Strong Roots Oil is certified organic, and JVN Complete Pre-Wash uses rosemary extract. indē wild Champi Pre-Wash Oil is lightweight, Dr. Groot Scalp Barrier Boost is a leave-in oil in serum, and Sangre de Fruta Botanical Hair Elixir is a styling cream with rosemary and lavender.

Massage a few drops into the scalp, leave it an hour or overnight, then shampoo twice.

Rosemary is one idea, but most of the hair oils I actually finish my hair with have nothing to do with it. These are the ones I would keep on the shelf next to a rosemary pre-wash, sorted by what they do.

For heat, read the label. Olaplex No. 7, OUAI, amika Superfruit Star, K18, shu uemura Essence Absolue, Fenty Beauty's The Flashy One and Chris McMillan's oil-mist all list heat protection up to 450°F, so they go on before the dryer. Moroccanoil Treatment is the argan oil classic, and Oribe Gold Lust pairs argan with jasmine.

For frizz and shine, Kérastase Gloss Absolu Glaze Drops use wild rose oil, Crown Affair's Radiance oil leans on Tsubaki camellia, and Pureology Hydrate Glow Catcher uses camellia seed oil too. Gisou's Honey Infused Hair Oil is made with honey from the brand's own bee garden. Davines OI uses roucou seed oil, Virtue uses Kalahari melon seed oil, and Mizani 25 Miracle is coconut, jojoba and sunflower.

Fable & Mane HoliRoots is the one pre-wash oil in this group, with safflower, sesame and castor, and it is the closest in ritual to rosemary. Bumble and bumble Hairdresser's Invisible Oil, L'Oréal Professionnel Absolut Repair 10-in-1 and RŌZ Santa Lucia round it out as lightweight everyday oils. CAIR by La Bonne Brosse's The Protective Oil, Rahua's Color Full Glossing Oil Mist, Rōz's Willow Glen Treatment Oil and Charlotte Mensah's Manketti Oil Pomade join the shelf for finishing and styling.

How I use them: two drops on dry ends, never the roots, and one more only if the ends still look dry an hour later.

What I would skip: a finishing oil on top of a scalp oil on the same day. It is the fastest route to flat, greasy roots.

Oils are the classic format, but a leave-in serum is easier to live with if you wash often or dislike the feel of oil on your scalp. Nécessaire Rosemary Serum is the most concentrated here, with a 70 percent rosemary blend and five percent Capixyl, and it goes on as a light leave-in. BondiBoost makes two, the HG Lock Drops Daily Hair Serum and the Intensive Daily Scalp Spray, both made for thinning hair. Dr. Groot Roll-On Hair Thickening Scalp Serum has a cooling metal tip and menthol, which makes it the one I reach for after a workout.

Agent Nateur holi (growth) 84 is named for its timeline: the brand says to expect visibly thicker, fuller hair in 84 days. Crown Affair The Overnight Repair Serum works on the lengths while you sleep, with flaxseed and chia. Dr. Groot Pre-Shampoo Exfoliating Detox Water clears the product buildup that can sit on top of a scalp serum, and St. Meto Mother Clay Hair Restoration Treatment uses calcium bentonite clay with rosemary and cedarwood oils to lift residue. BondiBoost HG Clarifying Pre-Wash Treatment and Dr. Groot Miracle In Shower are the wash-day options, Ceremonia Aceite de Moska is a pre-shampoo scalp oil, and Nécessaire Rosemary Leave-In Mask is the leave-in to try if you already use their serum. CAIR's Fortifying Scalp Serum, Sisley Paris's Revitalizing Fortifying Serum and Oribe's Serene Scalp Densifying Treatment Spray add more scalp-focused options to the row.

How to apply a scalp serum: part dry hair into rows, put the dropper or roller directly on the skin, then massage for a full minute.

What I would skip: switching products every two weeks. The 2015 study saw no significant change at three months, so give one routine at least that long before you judge it.

Wash day is where rosemary is easiest to keep up with, since you are already standing there. Innersense has the story I like most in this row. Greg and Joanne Starkman had long careers in the beauty industry and had seen how many harmful chemicals went into salon products, and the birth of their daughter, who was diagnosed with Williams syndrome, made building a clean brand feel more urgent. They launched Innersense in 2005 and later chose to go direct to salons. The Hair Renew Scalp Hairbath uses salicylate-rich fermented willow bark to help with flaking plus green coffee bean extract, and the Hair Renew Soothing Conditioner is its match.

Nécessaire Rosemary Shampoo pairs plant proteins and ceramides with a microdose of Capixyl, and the Rosemary Conditioner is a lightweight multi-protein formula that leaves no residue. BondiBoost HG Shampoo is vegan and built on aloe vera, and the HG Miracle Hair Mask adds argan, jojoba and castor oils without silicones. RŌZ Foundation Mask is a deep conditioner in a seafoam tube, and Dr. Groot Hair Thickening Scalp Conditioner uses biotin, encapsulated prebiotics and rosemary. BondiBoost HG Conditioner and Dr. Groot Hair Thickening Shampoo finish the matching pairs, and BondiBoost HG Volumizing Dry Shampoo covers the days between washes. Sisley Paris's Intense Nourishing Hair Care Mask, Rahua's Color Full Hair Mask, Ranavat's Glossing Hair Masque and goop Beauty's Nutrient Shinebath Hair Mask add more masks for the lengths.

A routine that works: pre-wash oil from the first row, then shampoo twice, then conditioner on the lengths.

What I would skip: a heavy mask on the scalp itself. Keep masks from the ears down and let the scalp products do their work up top.

Pick one rosemary hair oil or serum and use it on a schedule, a few times a week, for at least three months. Take a photo of your part in the same light on day one and again at month three, because day-to-day changes are too small to see. Massage matters too, so take a minute working the product in with your fingertips rather than just dripping it on. If your scalp gets itchy or red, stop, and see a dermatologist if shedding is sudden or patchy. Rosemary is a gentle habit, so pair it with good sleep and a steady routine. If you want to keep browsing, I also put together What the Best Shampoo for Thinning Hair Can Really Do and Bondi Boost.