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You read that right. Onions aren’t just delicious and nutritious for your insides, some believe this mineral-rich allium can benefit your outsides, too — namely, your hair.

A Google search reveals claims from hair loss prevention, to hair growth stimulation, to hair nourishment, to the ability to soothe an irritated scalp and ease dandruff — just to name a few.

While there isn’t enough research to say, conclusively, that onion juice can do any of these things, there are a spattering of small studies that show it may, indeed, be worth adding to your hair care routine.

It’s not a magic cure

Despite what you may have heard, onion juice can’t cure or prevent hair-loss conditions like male-pattern baldness or alopecia. If anything, it may be able to help manage symptoms, but we still have a ways to go before we can say that for sure.

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Luckily, there aren’t any serious risks to trying it out. (Just make sure to patch test before you go all in.) Even the onion-y scent can be masked.

Below, we dive into the research and give you some pointers on how to make your own onion juice shampoo.

Might be able to stimulate hair growth

Like we said, the research on this is very slim. One small study found regularly applying onion juice to hair increased hair growth in participants with a hair loss condition called alopecia areata.

Participants used onion juice in their hair twice a day. Of the 23 patients who applied the treatment, 20 saw hair regrowth after 2 months and 10 of the patients saw complete regrowth of their hair after 6 months!

So how does it work? That’s still up for debate, but some research points to onions’ high levels of sulfur, which promotes circulation, decreases inflammation, and might even promote collagen production.

The theory goes that these sulphuric properties help with hair regrowth, and prevents hair loss, especially in people who have mineral deficiencies.

Other hair-loss treatments

If you want to prevent hair loss, it might be best to start with treatments that are tried and true, such as these medications:

  • Minoxidil
  • Finasteride
  • Phenylephrine

There’s also a type of treatment that uses platelet-rich plasma injections to stimulate hair grown. But be warned, one session can cost up to $1,000.

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Might combat greying hair

The sulphur in onions is credited for another potential benefit: minimizing grey hair. As we age, free radicals can damage our hair by causing loss of hair density and pigment, aka greying.

Theoretically, if the sulfur in onion juice causes your scalp to increase collagen production, the collagen could fight these free radicals and lead to an anti-aging effect.

One study showed that topically applied anti-aging compounds could combat hair greying and hair loss, but more research would be needed to see if onion juice specifically could have this effect.

May soothe scalp inflammation

Because onion juice is a natural anti-inflammatory, it may also be used to treat an itchy, irritated scalp. A small study with mice showed that, topically applied, onion extract did have anti-inflammatory properties. But once again, there isn’t research that shows onion juice specifically treats scalp conditions.

One upside to the onion juice idea is that it’s super duper easy — and cheap — to do at home. Here’s the recipe:

  • Remove the skin of ~ 4 onions (any variety will do) and chop them into pieces.
  • Blend the pieces into a paste.
  • Use a cheesecloth to squeeze the juice into a bowl.
  • Either apply this juice straight to your scalp and hair or add it to your shampoo.

Optional: you might want to use a couple drops of an essential oil to try and mask the scent, but go easy. No more than five or six drops per ounce.

Like we said earlier, be sure to patch test before fully implementing this into your routine (especially if you’re incorporating any essential oils in the mix). And remember, in order to see results you may have to use it daily for a couple months. Yeah, you’re going to need to stock up on onions.

Hair products with onion juice

If you’re interested in the possible benefits of onion juice for your hair but are concerned about scent (and don’t mind paying a little extra), you can still give it a try with these products.

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None of the studies on the use of onion juice in hair indicated anything about their participants’ hair besides if they suffered from alopecia. Thus, it’s unclear if there would be different results for different hair types, concerns, or textures.

If you’re looking to try this treatment out, you should definitely adjust for your specific hair needs. If you’re concerned about hair growth but suffer from oily hair and don’t need the extra moisture, try just applying it to the scalp or directly to places where you lack density.

On the other hand, if you’re looking for growth and moisture, feel free to apply to your scalp and the length of your hair. You know your hair best, so adjust so you can see the best results for you.

Can’t get enough of alternative hair care? You might consider also using these ingredients in your routine.

Coconut oil

While there isn’t specific research on coconut oil and onion juice used in tandem, there’s some evidence that coconut oil helps hair growth by preventing breakage, protecting against protein loss, and soothing the scalp with its anti-inflammatory properties.

So we don’t see why you can’t use the two together to double up on their supposed hair strengthening properties.

Amla oil

Commonly found in henna dyes, amla oil has been shown (in rabbits and especially mice) to stimulate hair growth. Since henna can dye the hair, we recommend buying amla oil or amla powder directly.

Happily, there doesn’t appear to be any common adverse side effects, beside mild redness at the application site. And if you have sensitive eyes, throw on some goggles to avoid the sting. Oh and definitely stay away from this treatment if you have a known onion allergy.