Rosemary oil has been a hot topic of conversation lately on TikTok—and not for its delicious fragrance. Rather, the oil is garnering attention for its potential with hair growth. But is there any truth behind all the social media chatter? To learn more, we tapped New York City-based board-certified dermatologist Hadley King, celebrity hairstylist Dominick Pucciarello, and celebrity hairstylist, colorist, and Creative Director of Style & Color for L'Oréal Paris Jonathan Colombini. Plus, we’re sharing the best rosemary oil hair products to try now.
What are the benefits of rosemary oil?
It may help thicken hair. Research shows that rosemary oil may be as beneficial as Minoxidil—the active ingredient in Rogaine—for hair growth (but more on that in a minute).
It’s antimicrobial. According to King, “Rosemary oil has antimicrobial and anti-inflammatory properties" that can soothe the scalp.
It helps with dandruff. Those antimicrobial and anti-inflammatory properties “help to keep dandruff and scalp acne at bay,” says King.
It helps with breakage. Some hair thinning is due to breakage. According to Pucciarello, rosemary oil “helps to prevent thinning from aging or hormonal conditions.”
It’s safe for all hair types. Most everyone can use rosemary oil, although “If you have any allergic reactions, stop using the product and consult your dermatologist,” says Pucciarello.
Can rosemary oil help thicken hair?
Yes—well, probably. “A 2015 study compared rosemary oil to Minoxidil for hair growth and at six months, both groups saw significant increases in hair growth,” explains King. “This effect could be due to rosemary oil's enhancement of micro-capillary perfusion.” However, King says that Minoxidil is still “the most proven OTC option and works for both men and women.”
To get technical for a second, King explains that Minoxidil “is a potassium channel opener, causing hyperpolarization of cell membranes. Theoretically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood and nutrients to reach the follicles.” If you prefer to try rosemary oil, just know that more research is still needed. “The bottom line is that for oils, we need bigger, better studies in order to evaluate whether or not these ingredients may help with hair growth,” stresses King.
So, how long does it take to work? “Because of the hair growth cycle, any effects on hair growth may take six months to show up,” says King, adding that “The 2015 study with rosemary oil showed results at six months.”
How often should rosemary oil be applied?
It can be applied daily, or after every wash, says Colombini. "You can use rosemary oil on the hair anytime you want to replenish the hair’s natural oils or address a problem area," says the pro.
How should rosemary oil be applied?
"Rosemary oil can either be applied directly or via products," says Colombini. "If you’re hoping to address hair growth, apply directly onto the scalp and massage in for a couple minutes. If you’re hoping to address hair breakage or dryness, apply to the hair to act as a conductor to help transfer sebum, hair’s natural oils, onto the hair shaft, which acts as a protector." He also recommends using products with natural rosemary essential oils.
The best rosemary oil hair products
Rosemary oil can be applied in various product forms, from simple oil formulations to serums, shampoos, and treatments. Here are some we recommend.
Kiehl's Magic Elixir Hair Restructuring Concentrate
AROMATICA Rosemary Scalp Scrub
Aveda Rosemary Mint Purifying Shampoo
This article first appeared in Harper's Bazaar in April 2023.