Since we’re pretty much surrounded by screens all day, every day, you’ve probably seen the viral TikTok video touting the benefits of rosemary essential oil for hair, and now you want to slather your scalp in the stuff.

Before you do, though, keep reading because Amy Anthony, certified aromatherapist at NYC Aromatica, breaks down the benefits, drawbacks, and how to use it.

What, exactly, are essential oils?

“Essential oils are obtained from specific parts of plants—i.e. the root, seed, leaf, flower, rind, etc.—that we consider medicinal and spiritual herbs,” Anthony says. These aromatic plant parts are distilled to collect their volatile oils, which make up a very small percentage of the plant. As a result, it can take several to produce a small batch of essential oils, hence why they can be so expensive.

As Anthony notes, however, just because a plant is fragrant doesn’t mean you can derive essential oil from it. “For instance, lilac flowers have aromas—molecules that can be smelled—but if you put the plant material through the distillation process, you wouldn’t obtain essential oil,” she says. This is due to the chemical composition of the flower.

How can rosemary essential oil benefit hair?

Using rosemary essential oil to help promote both hair growth and prevent hair loss is a well-known Mexican practice. Rosemary essential oil feels cooling when applied to skin, but what it’s really doing is stimulating tissue, according to Anthony. This is part of what makes rosemary essential oil good for your hair and scalp. “I like to approach this from an herbalist perspective,” Anthony says. “Topically, when rosemary essential oil is properly diluted into a carrier oil and applied to the scalp, it cleanses and stimulates—it brings circulation to the scalp.”

This is where it’s important to understand the difference between an aromatherapeutic application versus a cosmetic application. While you may see rosemary essential oil on the ingredient list of hair care products, the oil is diluted down, “more-so for ‘fragrance’ purposes,” Anthony explains. So the percentage of rosemary essential oil in the formula will be much lower for cosmetic application than in a therapeutic product.

Who can benefit?

“Honestly, anyone who is looking to support their scalp through stimulating herbs in order to cleanse and wake it up,” Anthony says. “It is often cited for use with darker hair versus lighter hair, but I don’t see the need to make that distinction when working with the essential oil.” She says those distinctions are more for herbal rinses, which are made by boiling rosemary plant in water, which can darken hair.

How do you use rosemary essential oil for your hair?

“As a practitioner, I would create a product for a client, such as a scalp oil,” Anthony says. The rosemary would be diluted into a carrier oil, and may include other essential oils. “This would be applied on a schedule and have a dilution rate where rosemary may make up three percent of the overall formula,” Anthony says. (Note: That is a lot of essential oil.)

At home, you can blend two to three drops of rosemary essential oil into a couple tablespoons of carrier oil like coconut or almond oil, and then gently massage it into your scalp. Leave it on for a few minutes, and then wash it out with shampoo.

Anthony recommends using rosemary essential oil for your hair three times a week for two to three weeks. “The key is consistent use to stimulate the scalp…to a point,” she says. “Long-term use of essential oils may cause sensitization if not properly diluted or used in high—e.g., 5-percent or greater—dilutions over a long period of time,” she explains.

Who shouldn’t use rosemary essential oil?

“Rosemary essential oil is contraindicated for those living with epilepsy,” Anthony says. “This is due to its containing the chemical components of camphor and eucalyptol, which are found in several other essential oils—both of which are cleansing and stimulating,” she explains.

Also, it shouldn’t be used on infants or children under five years old—best to let your baby’s hair grow in on its own.

Ready to give it a try? Learn how to make rosemary oil at home in a slow cooker.

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