Mustard: a condiment for hot dogs, yes, but a haircare ingredient? To be fair, we're talking about mustard oil, rather than the yellow stuff in the squirt bottle (so please keep reading before reaching for the French's). It turns out, mustard oil does in fact have some benefits for both the hair and scalp. Extracted via a pressing of the mustard seed, it's long been used in Ayurvedic medicine to treat a variety of issues (hair and scalp problems among them). Conduct a quick Internet search and you'll see plenty of info touting it as a solution for everything from dandruff to hair loss, not to mention countless YouTube videos of women dousing their heads in it. So, how exactly can this little seed be so good for your hair? Ahead, certified trichologist and founder of the Gaunitz Trichology Method, William Gaunitz, Gretchen Friese, a certified trichologist with BosleyMD, and Dr. Jennifer Chwalek, board-certified dermatologist at Union Square Laser Dermatology in New York City, and trichologist Sophia Emmanuel unpack the mysteries around mustard oil.
Type of Ingredient: Hydrator and anti-inflammatory
Main benefits: Hydrates scalp and hair, has anti-bacterial and anti-fungal properties, may help promote hair growth.
Who should use it: In general, anyone looking to improve the general health of their hair and/or scalp, as well as those concerned with dryness, hair loss, or dandruff, says Friese. That being said, it can be very irritating, so it's important to proceed with caution.
How often can you use it: Generally speaking, it can be used as a weekly or monthly treatment.
Works well with: Other oils that also have hair and scalp benefits such as jojoba and coconut.
Don't use with: According to Chwalek, there are no known ingredients that shouldn't be mixed with mustard oil. However, it is important to do a patch test prior to using to ensure you can tolerate it.
Benefits of Mustard Oil for Hair
"Mustard oil is rich in monounsaturated and polyunsaturated fatty acids, such as omega 3s and 6s, various minerals including calcium, iron, and zinc, as well as antioxidants such as vitamin B and E," says Chwalek. In short, the tiny-but-mighty mustard seed is filled with a variety of good-for-your hair and skin nutrients; it's also a mainstay in Ayurveda, used to address everything from gum disease to parasitic infections to hair loss. It's worth noting that it isn't FDA-approved for oral consumption in the U.S. because it can contain a high concentration of toxic erucic acid, but it can be used topically on the scalp and hair, adds Chwalek. To that point, mustard oil has the potential to do the following:
- Reduces inflammation on the scalp: Those omega fatty acids and antioxidants we mentioned both provide essential nutrients to the hair follicle and act as anti-inflammatories.
- Has anti-bacterial and anti-fungal properties: This makes mustard oil a potentially good option to address issues such as dandruff and seborrhea, says Chwalek. In addition, mustard seed also has anti-parasitic effects, which make it effective against a particular type of mite found on the scalp, notes Gaunitz, who has studied and worked with mustard oil extensively.
- May help promote hair growth: Chwalek notes that one study of a topical herbal oil (which used mustard oil as the base) found it to be effective not only against dandruff, but also good for reducing hair shedding and promoting hair growth.There are several ways it can do this: First, there are the anti-inflammatory properties, which can help prevent inflammation-induced hair loss. Secondly, there's some evidence that certain compounds in mustard affect particular receptors in the hair follicle that play a role in controlling hair growth, notes Chawlek. And finally, for some people, hair loss can be caused by a parasite known as demodex folliculorum, one of two types of demodex mites that live on human skin, explains Gaunitz. These mites affect the hair follicle and impair hair growth; mustard seed is known to kill these mites, he adds. The big caveat? Demodex folliculorum feed on oil; as such, Gaunitz advises against using mustard oil on the scalp and instead says that tinctures made with ground mustard powder are a much better option (more on that to come).
- Improves overall appearance of the hair: While all of these benefits are largely centered around mustard oil's effects on the scalp, because it is so rich in fatty acids, it can also help smooth split ends and make your hair shinier, says Chwalek.
Hair Type Considerations
Mustard oil can be used for all hair types, but perhaps not all skin types. All the experts we spoke with agree that it can be extremely irritating—we're talking redness, stinging, even burning thanks to skin-irritating compounds such as (again) erucic acid and allyl thiocyanate, explains Chawlek. A patch test to ensure your skin can handle it is a must before you slather it all over your scalp, and those with sensitive skin should proceed with extreme caution. Similarly, it's often recommended to combine the mustard oils with other nourishing oils like baobab in order to minimize the likelihood of irritation. "Baobab is a skin-nourishing carrier oil that helps soften dry skin and penetrates very well into the skin," Emmanuel says. "It is used [to treat] other scalp disorders such as psoriasis and has a great amount of essential fatty acids."
How to Use Mustard Oil for Hair
While there is some science to back up the benefits of mustard oil, there are no studies verifying the best way to use it,"Chawlek points out. One option is to do what's called a "quick oiling": "Take about a teaspoon of mustard oil and massage it into your scalp for about five minutes immediately before shampooing," suggests Friese. Alternately, to up the ante, you can apply the same amount onto the scalp, then pop on a shower cap and let it sit for about 30 minutes, she says. The shower cap will trap heat and help the oil penetrate better. If you're going to do the latter, it's a good idea to combine the mustard oil with another oil; coconut is one good option, particularly if your hair is extremely dry, says Friese. This will both help minimize the likelihood of the mustard oil irritating your scalp and give you additional benefits from the secondary oil. (Either way, make sure you do that patch test first and follow up with a thorough shampoo.) Generally speaking, you could do either of these treatments weekly or monthly, says Chawlek, though again she notes that this is based on anecdotal, rather than scientific, evidence.
Back to Gaunitz's point about using powder: he says that the best way to reap the topical benefits of mustard is to create a tincture with ground mustard seed powder, rather than using it in oil form. (He also adds that it's very challenging to find pure, high quality mustard oil and that many of the products on the market cut it with all kinds of vegetable oils that can ultimately counteract the benefits of the mustard.) He suggests combining 1/4 teaspoon with two ounces of water for a topical application, though underscores that this needs to be done with caution given the likelihood of irritation.