Cardi B Says She Washes Her Hair with Onion Water

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Cardi B just shared the secret to her sleek, shiny hair. It's not an expensive leave-in conditioner or fancy salon treatment. No, it's onions.

"My last two washes, I been boiling onions and using the water to wash my hair," she explains in the caption of a recent Instagram post featuring a photo and video of her hair. First, there's a photo of her long hair from the back — supposedly an image of what her hair looked like before using her DIY treatment. Then, there's a video of her showing off smooth strands that look healthy and strong with noticeable shine, possibly thanks to onion-infused water.

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"I used to do this six years ago when I started my healthy hair growth journey. I stopped cause I got really lazy," she continues in the caption. Okay, but does the onion water leaves behind smell? "It's odorless," writes Cardi B. "I notice that it's been giving a shine to my hair," she adds.

The post was met with heaps of positive comments, including a message from the official Instagram account: "If Cardi washes her hair with onion water, we wash our hair with onion water 😌." Others confirm they've used onions, specifically onion juice, for hair treatments themselves, and some called out the fact that this hair secret may be tied to the "WAP" singer's Dominican heritage.

The video of Cardi B's hair after her DIY shine treatment might be convincing enough to make you run to the grocery store to pick up some onions and give the hack a try for yourself. But experts acknowledge there are real merits to the DIY technique.

"According to a few studies, topical onion juice can be a good natural treatment for non-scarring alopecia [a hair loss condition]," explains Tiffany St. Bernard, Ph.D and CEO of HairDays. This is likely due to the fact that onions contain sulfur and have antioxidant properties, she adds.

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As for Cardi B's claims that onion water adds shine to her hair? "Hair shine could be due to a number of different factors and products, but it would be safe to say that if Cardi B is using onion rinses regularly and seeing results, they could be contributing to that healthy shine," says St. Bernard. Additionally, using onion juice as a rinse or treatment before using shampoo or conditioner shouldn't leave behind a smell, says St. Bernard. "You can follow the onion rinse with essential oils or an apple cider vinegar rinse to remove any potential lingering odor," she suggests.

Using onion juice, such as Cardi B's boiled onion water concoction, should be safe to use on all hair types, according to St. Bernard. However, you shouldn't try this hair hack if you're allergic to onions. "Whether you are aware of having allergies or not, you should always test new products or treatments on a patch of skin before applying them to your entire scalp," adds St. Bernard. She also recommends chatting with a licensed dermatologist or trichologist to treat specific hair concerns.

If you're not sure about using onions for hair health, there are other alternatives to promote shine and growth. "Rosemary has been clinically proven to be effective at promoting healthy hair growth," says St. Bernard. "Exercising and maintaining a healthy balanced diet will nourish your hair from the inside," she adds. Plus, you can prioritize using protective styles to avoid unwanted breakage.

You can file this celebrity hair hack under don't knock it until you try it. (Up Next: Ricki Lake Shared a Dramatic Before-and-After Image of Her 'Debilitating' Hair Loss)