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To quickly eliminate the onion smell from hair, rinse your scalp with a mild clarifying shampoo and lukewarm water. Follow it up with diluted acidic solutions, such as apple cider vinegar and lemon juice. They help neutralise sulphur compounds, which cause the onion’s pungent odour.
Benefits of using onion juice on hair
The sulphur compounds in onion juice improve blood circulation to the scalp and promote collagen production, responsible for healthy scalp cell growth. Onions also contain flavonoids (quercetin and kaempferol) that prevent scalp inflammation.
Applying the onion juice is easy. The difficult part is removing its sharp smell that can linger for a day or more, even after shampooing your hair. Let’s understand why the odour stays on.
Why does the onion smell last in the hair?
When onions are cut or blended, their cell walls are crushed, releasing some volatile sulphur compounds. They bind to the hair’s keratin and mix with the scalp’s sebum, which is why the smell tends to last.
The compounds that cause the onion odour are:
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Thiosulfinates: These compounds directly cause the onion’s pesky smell.
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Sulphides and disulphides: 80%-93% of the onion’s sulphur content consists of dipropyl disulfide. Although only a trace of diallyl disulfide is present, it is enough to cause the onion smell.
These oil-soluble compounds don’t go away in a simple hair wash. So, you may need natural or acidic neutralising agents that can counter these sulphur compounds.
How long before the onion smell clears out?
Your hair type is vital in determining how long the onion smell sticks around in your hair. A thorough shampoo and wash can help remove the onion odour. But factors like humidity and sweat can trap the sulphur compounds in your cuticles, bringing the smell back.
Mistakes that make the onion smell worse
If the onion odour lasts longer, it depends on how you apply it. Here are some mistakes one can make:
- Leaving the onion juice in your hair overnight
- Applying it to an unclean and dirt-laden scalp
- Not washing your hair properly
- Using excess onion juice
- Unstrained juice that can leave onion particles in your hair
- Tying your wet hair immediately after shampooing
How to apply onion juice to your hair?
Before we mention how to remove onion smell from hair naturally, let’s walk through the application process, which makes rinsing it out easier:
- Part your hair into 4 separate sections.
- Use a brush or dropper to apply the juice directly to the scalp (not to the lengths) and to avoid overapplication.
- Gently massage the juice in circular motions for 5-10 minutes.
- Leave it on for 30-45 minutes.
Always patch–test onion juice before you apply it to your scalp.
How can you prevent the onion smell before even applying it?
Diluting the onion juice with natural ingredients can help mask its sharp smell. Here’s what you can use to dilute onion juice:
- Coconut oil blocks the direct absorption of sulphur compounds into the hair shaft. You can mix it with onion juice in a 1:1 ratio as a pre-shampoo hair mask.
- You can use aloe vera gel’s fresh scent to reduce the onion juice’s pesky odour.
- A few drops of tea tree or lavender oil can also help cover the onion smell.
- The onion juice can even be diluted with rose water to offer a mild floral scent.
How to remove onion smell from hair with easy home remedies
Follow this three-step routine to remove onion smell from hair after washing:
Step 1 - A two-step cleanse with lukewarm water
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Wet your hair thoroughly with lukewarm water, which helps loosen scalp oil and onion residue, without exposing the hair to excessive heat.
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Apply a mild sulphate-free clarifying shampoo to rinse out the onion smell. Regular shampoos can remove everyday buildup, but aren’t strong enough to remove sulphur compounds.
Step 2 - Neutralise the odour with an acidic rinse
Acidic rinses chemically break down the alkaline nature of sulphur compounds. You can choose one of the two acidic rinses:
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Apple Cider Vinegar (ACV): ACV may help clear the residual buildup and the lingering onion smell. Mix 2 tablespoons of ACV with 1 cup of water to neutralise the odour. Note: Undiluted ACV can cause dryness.
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Lemon juice: It also contains citric acid, which can counter the alkaline properties of sulphur compounds. Mix half a lemon’s juice with 1 cup of water, apply it to the scalp, leave it for a few minutes, then rinse thoroughly.
Step 3 - Conditioning and the final rinse
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Apply conditioner from mid-length to the ends to keep your strands well moisturised.
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Rinse with cold water to close the cuticles and lock in the moisture.
Alternative natural remedies to remove onion smell from hair
If an acidic rinse is not suitable, you can choose other remedies that match your hair type:
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Herbal shikakai and Reetha for dry or chemically-treated hair:
These time-tested Ayurvedic hair care remedies, when soaked overnight, produce a mild lather that can clean your scalp without stripping away vital moisture.
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Black coffee rinse for dark hair
Brew some black coffee and let it cool completely. Pour it through your hair as a pre-shampoo rinse. Leave it for a few minutes and shampoo as usual. Brewed coffee acts as an odour-absorbing and masking agent.
Note: If you have coloured or light hair, do a patch test before applying it, as coffee tends to stain.
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Essential oils for all hair types
A few drops of essential oils (like tea tree, lavender, rosemary, or peppermint) mixed into the shampoo can also help remove the onion smell easily.
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Baking Soda for an oily scalp
Baking soda can absorb excess odour and buildup.
Note: Baking soda’s high alkalinity can also cause dryness. If you have coloured or chemically-treated hair, avoid using it entirely.
Onion juice is a tried-and-tested remedy that may nourish hair cuticles and help treat dandruff. However, it cannot be treated as the only homemade solution for boosting hair growth; it can be part of a larger haircare routine that includes Traya’s Nourish Hair Oil.
Frequently Asked Questions -
1. How can hair type be related to the onion smell?
How long the onion smell remains highly depends on your hair:
- Scalps with high sebum levels may trap sulphur compounds easily. Hence, thoroughly rinse your hair to get rid of the onion smell.
- Fine hair indicates hair thinning on the scalp. Since there is less surface area for sulphur molecules, they can be removed easily.
- The onion smell tends to absorb deeply into highly porous, chemically treated, or heat-damaged hair.
2. How many times can you apply onion juice in a week?
You can apply onion juice 2-3 times a week only if it doesn’t irritate your scalp. Conduct a patch test first or massage it once a week to ensure it doesn’t cause scalp inflammation or a burning sensation.
3. What is the best time to apply onion juice to your hair?
Mornings are the best time to apply the onion juice. You can leave the hair mask on for 30-45 minutes before washing it off and starting your day.
At night, if you lie down or fall asleep, the onion juice odour may get trapped in your pillowcase, making it harder to rinse it out.
4. Can apple cider vinegar damage your hair?
Diluted apple cider vinegar can help clean your scalp of dirt buildup and is most efficient when diluted. However, undiluted ACV or overusing it can strip your hair of natural oils.
5. Does onion juice alone emit a bad odour from your hair?
Apart from onion juice, the bad odour that keeps coming back in your hair can also stem from sweat buildup, oil remnants, poor scalp hygiene, dandruff, or fungal overgrowth.
References:
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