The way my hair smells right now should be a crime!
The stinky rotten eggs-like odor is getting me so high that I just quit caring about what my hair looks like.
To add more insult, one of my friends sarcastically uttered she could smell my keratin treatment from 3 miles away! Awkward. I know.
I only had my keratin treatment done a few days ago. I got past the first wash. So what’s the reason for the bad smell still lingering?
I decided to meet up with my hairdresser for a coffee to chat about it and get some valuable tips on how to fix it fast.
If you share a similar dilemma, hang around to find out how you can get rid of the smell after a keratin treatment without overthinking it.
Table Of Contents
- Why Does Hair Smell Bad After Keratin Treatment?
- 1. You May Have Had A Formaldehyde-based Keratin Treatment
- How Long Does Keratin Treatment Smell Last?
- How to Get Rid of Smell After Keratin Treatment
- Best Products to Eliminate Keratin Treatment Smell
- Other Tips to Help With Smelly Hair After Keratin Treatment
- Avoid Doing These …
- Final Thoughts
Why Does Hair Smell Bad After Keratin Treatment?
It’s normal for keratin-treated hair to smell for a few days – said my hairdresser. The lingering stench is just the byproduct of keratin and other chemicals in the treatment. It may last for up to 4 shampoos until it’s completely gone. So don’t panic.
But for those who experience a persistent strong smell, like burnt hair, especially after washing, there are 3 reasons:
1. You May Have Had A Formaldehyde-based Keratin Treatment
Among the many keratin treatments, the most popular one is the Brazilian Blowout. The BB is highly effective for its ability to repair severely damaged hair, straighten any hair type, and eliminate frizz instantly. The downside of the treatment, though, is its strong chemicals. And the one chemical that raises eyebrows is Formaldehyde.
Formaldehyde can make any hair poker straight and glossy. But the dark side of this chemical is its volatile nature. Formaldehyde is a pungent-smelling gas that releases toxic fumes when heated. Although it’s banned in the US, keratin treatments containing the legally allowed 0.2% concentration are still around.
Such treatments may also contain another chemical component – Ammonium Thioglycolate, a reducing agent that breaks cysteine amino acid bonds to reconfigure the hair. It releases a byproduct of sulfur by depilating the keratinous fibers and breaking disulfide bonds.
Luckily, I didn’t have a formaldehyde-based keratin treatment. Hair salons in London are not even allowed to do them. My hairdresser used the GK Hair keratin system.
So how do you get rid of the Formaldehyde smell in the hair?
Hair salons that use formaldehyde treatments use many precautionary measures like wearing protective face masks, plenty of ventilation, and even air purifiers.
Ventilate, ventilate, ventilate! The best way to eliminate the smell is to stay in well-ventilated spaces. Use an air purifier in your home to help air out the bad smell. (more on this below)
2. Burnt Hair
Almost all keratin treatments require high heat of up to 450F to seal the solution into the hair. The likeliness of the flat iron sizzling the cuticle layer is also very high. That’s why hair smells burnt after a keratin treatment.
If you’ve ever tried burning a piece of hair, you’ll know what it smells like – a sulfurous stench or fireworks comes to mind.
Why does burnt hair smell bad?
Hair is mostly made of protein (keratin). It’s also composed of 50.7% carbon, 20.9% oxygen, 17.1% nitrogen, 6.4% hydrogen and 5.0% sulphur.
Keratin is rich in cysteine, a sulfuric amino acid chain that forms disulfide bonds between molecules to create each hair strand’s structural strength and resistance. 
Amino acid cysteines, which contain reactive sulfur atoms, form the disulfide bonds, the strong connection that links the keratin molecules, preventing them from slipping past each other.
When hair burns, the high heat percolates the cuticle layer to disrupt the disulfide bonds. As a result, the sulfur in the chains of the amino acids thermally decomposes into hydrogen sulfide – or volatile sulfur compounds (VSCs). Hence the reason why hair smells like sulfur after straightening.
“You’ve burned the cuticle and molecule element of the hair shaft, which is why you still smell the on-fire stench even when your hair is clean.” Penny James
Trichologist, talking to - Makeup.com
3. A Combination of the Chemical Process and Heat
The chemicals used may be formaldehyde-based or not, but they will contain some thio compound like ammonium thioglycolate that breaks or rearrange disulfide bonds.
Add to that the high heat from the flat ironing, and you get a combination of chemicals and heat bound to release some form of odor.
How Long Does Keratin Treatment Smell Last?
The keratin treatment smell may last 3 – 4 washes, depending on how you care for your hair. During this time, it’s essential to keep your cool and work with products that neutralize odors rather than mask them.
So there you have it. My hairdresser went rather sciency about the possible reasons why a keratin treatment makes hair smell bad.
She then whips out her iPad from her handbag to show me what I have to do next – the solutions to fix it fast.
How to Get Rid of Smell After Keratin Treatment
The best way to get rid of the smell after a keratin treatment is to use odor-neutralizing products and ventilate the hair as much as possible. You can also use fragranced hair masks, leave-in conditioners, and hair fragrance mists, but these products will merely mask the odor. It would be best if you got to the root of the source to eliminate the volatile sulfur compounds.
A Word Of Caution:Do not attempt DIY solutions that involve baking soda or vinegar rinses – more on this below.
Let’s start with the products that my hairdresser highly recommends:
Best Products to Eliminate Keratin Treatment Smell
Defunk Hair Odor Neutralizing Tonic
The Defunk odor neutralizer tonic is a lightweight spray formulated with plant extracts like rosemary, lemon, lavender, and vegetable enzymes to break down odor-causing compounds. Rather than masking odors, it expels them from the hair. You can also use it as a post-workout treatment to prevent sweat from ruining your keratin treatment and prolong your next wash day!
Just spray it generously on your hair and scalp, and let it eradicate the offensive odors from the source.
The product is also sulfate-free and doesn’t require a full-on wash, making it an excellent solution for getting the burnt smell out of hair without washing.
Mirai Clinical Purifying and Deodorizing Hair Shampoo
Get this deodorizing shampoo if you’re already past the 3 days of no washing.
The Mirai clinical purifying shampoo contains Japanese Persimmon extract, proven to eliminate odors from fabrics, nonenal odors, and odors often associated with hormonal imbalances and aging. Japanese Camellia extract adds a fancy floral note that lingers softly in the hair to give you an uplifting mood boost.
Bonus point: This shampoo is sulfate-free and contains no harsh chemicals. It won’t strip away keratin from your hair, so you can use it when necessary. The more you use it, the more it will help disperse the smell.
If you’re worried about overwashing your hair for fear of ruining your keratin treatment, here are 2 options that offer waterless cleansing while also eliminating odors.
Related: Best shampoo for smelly scalp.
Waterless Fragrance Mist Rose & Peach
This is by far the best waterless washing solution to remove odors from keratin-treated hair. The mist rose & peach shampoo from this buzzy new brand Waterless contains a touch-activated scent that keeps the hair smelling fresh all day. Simply shake and spray it over your hair generously – it adds a sweet, refreshing scent on the go. You can travel with it, use it after a gym workout, or for a quick refresh. It will save you from embarrassment.
Plus, unlike other hairsprays, it doesn’t contain alcohol. Alcohol has a rapid evaporation effect, which you must avoid as it can exacerbate volatile sulphuric compounds and denature proteins (melt keratin in the hair).
How do astronauts wash their hair in space?
They use the no-rinse shampoo. Massage it into the hair until it gets wet, then use a soft absorbent towel to dry it. No water needed.
The no-rinse shampoo is ph-balanced and formulated to eliminate odors.
Approved by thousands of hospitals for medical use, it leaves the hair sparkling clean. It’s a non-irritating reliable shampoo for anyone looking for an effective way to remove unwanted odors from the hair, be it after bleaching or Brazilian Blowouts.
Briogeo Scalp Revival Charcoal Biotin Dry Shampoo
This is my favorite dry shampoo right now.
Charcoal is proven to detoxify and absorb impurities. So this dry shampoo releases agents that trap impurities in the hair to leave it feeling pure and fresh.
The product website also states it’s safe for color-treated, keratin-treated, chemically-treated, and relaxed hair.
OUAI Rose Hair & Body Oil
The OUAI hair oil adds rose hip and absinthium essential oils fragrance to the hair with its nourishing and hydrating formula. It’s great for an energizing pick-me-up, nights out, or holidays.
Related: Best oils to use after keratin treatment.
Arvazallia Argan Oil Hair Mask
This keratin aftercare hair mask is all about its heavenly smell.
It’s like a tropical paradise and yet not overpowering. Allow it to melt into your hair with the help of a plastic bag or shower cap. Not only does it intensely nourish your hair, but it also keeps the bad odors at bay.
Pacifica Beauty Island Vanilla Hair Perfume
And lastly, you’ll be silly not to consider a hair perfume.
For unexpected occasions, last-minute plans, or quick refresh at parties, a hair perfume will help you relax and not be too self-conscious in tight public spaces. You don’t want people staring at you, thinking you’ve just dropped a stinky fart. Do you?
This product discretely slips into your handbag for quick refreshes. It will make you smell sexy with its subtle blend of patchouli and wild berries.
Other Tips to Help With Smelly Hair After Keratin Treatment
Keep Your Space Well-Ventilated
Keep your house ventilated all the time to air out the odor. Open your windows when weather permits and use fans. If you don’t have good airflow in your home, the odor from the hair can build up and become overwhelming for yourself and everyone around you.
Get An Air Purifier
Air purifiers help to remove airborne particles, including odors, from the air.
I’ve got one at home, and every time I would go anywhere near it, its auto-detection mode would trigger the fans to blast at full speed with a constant red light, indicating bad air quality.
It has laser dust and odor sensors that constantly scan the surrounding air quality to adjust the fan speed in real-time to purify the air. It’s also pretty silent, so that you can use it in the bedroom with adjustable timers.
Do Not Keep Your Hair Moist
After washing your hair, dry it as fast as possible. Damp hair traps odors, and if you’re air drying, the evaporation process will intensify the odors creating a musty and repulsive smell that is far more noticeable. To avoid this, try using a blow dryer in a low or moderate setting.
If you’re short of time, focus on drying your roots first, as this is where most of the moisture concentrates. Once your roots are dry, give your ends a quick blast of heat.
Change Your Pillowcase Every Night
Your hair comes into contact with your pillowcase overnight, which absorbs the smell. The smell then transfers back onto your tresses if you’re laying your head on the same pillowcase the next day after washing your hair.
Washing your pillowcases and bed sheets more often will help progressively eliminate the odor from keratin-treated hair.
Change it every night. Preferably, get a set of silk pillowcases as silk is less absorbent, has good temperature control, and has a cooler surface area. It prevents sweaty scalp and hair, therefore eliminating odors and frizziness.
Related: How to not ruin a blowout while sleeping.
Brush Your Hair Regularly
Brushing your hair regularly helps to break air pockets that hold on to the stench. Brushing helps to dissipate the odors. Remember, the denser your hair is, the more the odors will remain trapped and intensify. If you loosen up your tresses, it helps to air out and disperse the bad smell.
Related: Best brush to use on keratin-treated hair.
Next Time, Check for Formaldehyde-free Treatments
To avoid smelly hair after a keratin treatment next time, choose a same-day wash keratin treatment that is formaldehyde-free. There are plenty of new options on the market now that can also be done in the comfort of your home without any risks.
Which keratin treatments do not contain formaldehyde?
Check out our best formaldehyde-free keratin treatments to see the available options. Our best pick is the GK Hair keratin treatment.
Avoid Doing These …
You’ll find plenty of DIY recipes online that show how to stop smelly hair, including baking soda. While it may be true, it will cause more harm than good in the context of a keratin treatment.
Will baking soda remove keratin treatment?
Yes. Baking soda is highly alkaline and is a gritty substance that can strip keratin coating from the hair. So avoid it.
Apple Cider Vinegar
Apple cider vinegar is not harmful per se but acidic and is known to break down protein . In fact, apple cider vinegar is often used to fix protein overload in hair. People often use ACV as a clarifier – to strip the hair from buildup. This may strip keratin from your hair.
“You should also try not to use it right before or right after a chemical treatment, such as a coloring or keratin job, because the pH can affect the treatment you’re having done.” Anita Sun
Hairstylist at Eliut Salon. - Real Simple
Honey, Cinnamon, Lemon Juice, or Aloe Vera Recipes
Honey or aloe vera can make hair sticky, attracting more dust, oil, and dirt.
This is not good for keratin treatment for 2 reasons. If the keratin in your hair is still fresh and settling in, it may cause uneven patches and clumps and move the keratin from one area to another in the hair. Secondly, it will force you to wash your hair with a stronger shampoo to remove the stickiness.
Avoid lemon juice because it’s acidic and has a bleaching effect. It will disintegrate and dissolve keratin from your hair. Unless it’s well-balanced with other ingredients, please don’t use it.
Cinnamon may be good for neutralizing the smell and adding a warm scent, but avoid anything that will cause you to wash your hair unnecessarily.
Washing Your Hair Too Early
The smell may frustrate you and compel you to reach out for a shampoo as quickly as possible, breaking the rule of not washing the hair for 3 days. If you did a same-day wash keratin treatment, that’s ok. But other types that have a downtime period must be respected.
What happens if you wash out keratin treatment early?
Washing hair after a keratin treatment earlier than the recommended period can strip the freshly applied keratin and cause uneven patches. When the treatment specifies a waiting period, it’s because the treatment needs time to bind to the hair and absorb properly. Not respecting this rule can reverse the process, leave your hair in its pre-keratin state, and frizzed up in some parts.
Don’t be the girl with stinky hair no one want to sit next to.
Keratin treatments make hair smell. You cannot avoid it. Due to the chemicals, the high heat during the process, or a combination of both, some sulfuric oxide particles will land in the mass of your hair.
All you need to do is use good products that don’t just mask the odors but neutralize them from the source.
Please share this article with a friend who also struggles with this issue.
References & Citations
- Beneficial Effects of a Sulfur-Containing Supplement on Hair and Nail Condition
Retrieved on 29 August 2022.
- Yagnik, Darshna et al. “Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression.” Scientific reports vol. 8,1 1732. 29 Jan. 2018, doi:10.1038/s41598-017-18618-x
Retrieved on 29 August 2022.
Camelia loves all things creative and glamtastic.
She can color hair, perform keratin treatments, bleach hair, and even cut curly hair. She is our go-to person whenever we have hair treatments and styling questions.
She's also currently training as a freelance makeup artist and is passionate about helping others feel beautiful in their skin. When she's not writing or doing hair, she's usually spending time watching British period dramas.