Quick Summary:
Hair smoothening side effects are one of the most searched topics around this treatment — and one of the least honestly answered. Most salon content either dismisses the question entirely or lists every possible risk without context. This blog does neither. It walks through what's genuinely normal after smoothening, what's a sign something went wrong, and most importantly — what causes most problems and how to avoid them before they happen.
Hair smoothening is one of the most popular treatments we do at PD's Beauty Salon — and also one of the most Googled when something feels off afterwards. Clients search "hair smoothening side effects" not because they're regretting the treatment, but because something doesn't feel quite right and they want to know whether to worry.
Most of the time, the answer is no. But sometimes the answer is yes — and knowing the difference matters.
This blog covers everything honestly: what's a normal part of the process, what's a sign something went wrong, what causes most problems, and what you can do to avoid them before your next appointment.
First — What Hair Smoothening Actually Does to the Hair
Before talking about side effects, it helps to understand what's actually happening during the treatment — because most side effects are a direct result of how the chemistry works.
Hair smoothening uses a chemical relaxant to break the disulfide bonds inside each hair strand — the bonds that give hair its natural curl, wave, or frizz pattern. Once broken, heat is applied to reshape those bonds in a straight position, and a neutraliser seals them there. The result is a restructured hair strand that holds a flat, smooth shape.
This process is effective. It's also demanding on the hair's internal structure — which is exactly why the health of your hair going in, the products used during treatment, and what you do afterwards all directly determine whether the experience is problem-free or not.
What's Normal After Hair Smoothening
These are things clients commonly experience and worry about unnecessarily:
Hair feeling slightly stiff or heavy in the first 72 hours
The bonding process takes time to fully complete. In the first two to three days, hair can feel different from how you expected — slightly rigid or heavier than usual. This is normal and settles completely once the treatment has set.
Mild scalp sensitivity for 24–48 hours
The chemical relaxant used during smoothening makes contact with the scalp during application. Mild sensitivity, slight tenderness to the touch, or a faint tingling sensation in the 24–48 hours after treatment is common. It resolves on its own and doesn't require any treatment.
A temporary flat appearance
Some clients feel their hair looks too flat or lacks volume immediately after smoothening. This is the treatment working — the cuticle is sealed flat. It softens slightly over the first week as the hair settles into its new structure and begins to move more naturally.
Slight smell from the chemicals for the first few days
Professional-grade smoothening products have a distinct chemical smell that lingers for a day or two. It dissipates completely after the first wash. If the smell persists well beyond the first wash, mention it to your salon.
Hair fall during the first wash
Some hair fall during the first post-treatment wash is normal — particularly loose or already-shedding hair that the treatment has dislodged. If it continues beyond the first two washes, that's worth paying attention to.
What's Not Normal — Signs Something Went Wrong
These are signs that something in the treatment or aftercare process needs attention:
Significant hair breakage
Not shedding — breakage. If your hair is snapping at the mid-shaft or ends in the weeks after smoothening, the treatment has likely been applied to hair that wasn't strong enough to handle it, or the processing time was too long. Breakage that continues beyond two weeks needs a salon consultation.
Extreme dryness that doesn't respond to conditioning
Some dryness is expected — the treatment strips natural oils along with the bonds. But extreme dryness that doesn't improve with conditioning suggests the treatment has damaged the hair's moisture barrier. A professional deep conditioning or protein treatment is needed, not just home care.
Scalp irritation, redness or sores that persist beyond 48 hours
Mild scalp sensitivity after smoothening resolves within two days. Persistent irritation, visible redness, or sores on the scalp are a reaction — either to the product used or to contact with a sensitive scalp that wasn't identified beforehand. This needs medical attention, not just a wait-and-see approach.
Hair texture becoming permanently rough or coarse
Smoothening should never make hair rougher. If your hair feels significantly more coarse or rough than before the treatment — particularly after it's been washed several times — the treatment has caused damage to the cuticle structure. This is almost always linked to overprocessing or incorrect product application.
Uneven results — straight in some sections, frizzy in others
Patchy results where some sections hold, and others revert are almost always a technique issue — uneven application, inconsistent heat, or sections that weren't properly processed. If this happens, contact your salon within the first two weeks while the treatment is still fresh enough to address.
Hair loss beyond normal shedding
If significant clumps of hair are coming out during washing — not the loose strands you'd normally lose — this needs attention. Continued heavy hair loss beyond the first wash is a sign of damage that requires professional assessment.
The Most Common Causes of Smoothening Side Effects
Most problems from hair smoothening are preventable. Here are the real reasons things go wrong:
Hair that wasn't assessed properly before the treatment
This is the most common root cause. Damaged, over-processed, bleached, or brittle hair does not have the structural integrity to handle the chemical process of smoothening. Applying it anyway — because a client wants it or because the salon doesn't do a proper pre-treatment assessment — is where most breakage cases start.
A proper hair assessment before smoothening should check: current damage level, previous chemical treatments, hair porosity, and scalp condition. AtPD's Beauty Salon, this assessment happens before every smoothening appointment — it's the step that protects the client from problems downstream.
Low-quality or formaldehyde-based products
Not all smoothening products are equal. Budget products and older formulas often contain formaldehyde — a chemical that produces faster results but at a high cost to hair health and with genuine concerns around salon safety during application. Professional-grade, formaldehyde-free products are slower but significantly safer. Unusually cheap smoothening services in Delhi are often cheap for this specific reason.
Overprocessing — leaving the chemical on too long
The chemical relaxant needs to be timed precisely. Too short and results are uneven. Too long and the hair's bonds are damaged beyond what neutralising can fix. Overprocessing is a technician error — it happens when a salon is rushed, when timers aren't used properly, or when an inexperienced technician is handling the treatment.
Applying smoothening on top of existing chemical damage
Hair that's been heavily coloured, bleached, or previously relaxed has compromised structural integrity. Smoothening on top of this without proper assessment is one of the most reliable ways to cause breakage. For hair in this condition, nanoplastia is almost always a safer option — it repairs while smoothing rather than restructuring already-fragile bonds. We cover this in detail in our nanoplastia vs smoothening comparison.
Wrong aftercare — particularly the wrong shampoo
Sulfate shampoos used after smoothening strip the treatment and the hair's moisture simultaneously. This is the most common aftercare mistake and the one that causes the most downstream problems — dryness, frizz returning early, and texture deteriorating faster than it should. We cover the full aftercare picture in our hair smoothening maintenance guide.
Who Is Most at Risk of Side Effects
Not everyone who gets hair smoothening will experience problems. But certain hair types and situations carry higher risk:
Previously bleached or highlighted hair — The bleaching process raises the cuticle and depletes protein, leaving the hair significantly more porous and fragile. Smoothening on bleached hair needs an especially careful assessment and is often better served by nanoplastia.
Fine or low-density hair — Fine hair has less structural mass to absorb the chemical process. Side effects like breakage and extreme flatness are more common in fine hair than in thick, coarse hair.
Hair that's been rebonded before — Previously rebonded hair has already had its bonds restructured once. Smoothening on top of this needs careful consideration — the bonds are working from a different baseline than virgin hair.
Scalp conditions — psoriasis, eczema, active dandruff — Chemical contact with a compromised scalp can significantly worsen existing conditions. A scalp consultation before any chemical treatment is the responsible approach.
Hair that's been through back-to-back chemical treatments — If you've had a colour, keratin, or any other chemical treatment within the past four to six weeks, the hair needs time to recover before smoothening is applied.
How to Avoid Side Effects — Before, During and After
Before your appointment:
Go to a salon that does a proper hair and scalp assessment before starting. Not a brief look — an actual assessment of damage level, porosity, and previous treatment history. If a salon is willing to apply smoothening to your hair after a two-minute glance, that's a sign worth paying attention to.
Ask specifically what product brand and formula they use. Formaldehyde-free, professional-grade products are the standard at any salon worth trusting with this treatment.
Be honest about your hair history — colouring, previous treatments, heat damage. The assessment can only be as accurate as the information you provide.
Don't book smoothening within four weeks of a colour or bleach appointment without a strand test first.
During the treatment:
The processing time should be monitored and timed. A salon that leaves product on without checking is not following correct procedure.
Mild scalp tingling is normal. Burning or significant discomfort during the treatment is not normal — tell your technician immediately.
After the treatment:
Switch to a sulfate-free shampoo immediately and maintain it throughout the treatment's life. This is the single most impactful aftercare decision.
Follow the 72-hour rule without exception — no washing, no tying, no sweating.
Book a professional hair spa every four to six weeks to maintain moisture and protein balance. Hair that's been through a smoothening treatment depletes protein faster than untreated hair — the spa replenishes what the treatment and daily environment remove. We recommend this specifically in our hair spa guide.
If anything feels wrong in the first two weeks — unusual breakage, persistent scalp irritation, significantly uneven texture — go back to the salon and have it assessed. Most problems caught early are fixable. Left too long, they compound.
A Note on Formaldehyde in Smoothening Products
This comes up frequently enough to address directly. Formaldehyde-containing smoothening products are still used in some salons in Delhi — particularly at the lower price points. Formaldehyde produces visible results quickly, which is why it's still used. It also releases fumes during application that are harmful with repeated exposure, and it's harsher on the hair's internal structure than modern formaldehyde-free alternatives.
Professional salons using quality product ranges have moved away from formaldehyde-based formulas. If you're comparing salons and one is significantly cheaper than the others for what appears to be the same treatment — the product is almost always where that gap is. It's worth asking directly.
"I tell every client who sits down for a smoothening consultation: the most important thing we do is the assessment before we start. Not the product. Not the technique — though both of those matter. The assessment. If we look at your hair and decide it's not in the right condition for smoothening right now, we'll tell you that honestly and suggest what it actually needs first. That conversation is what protects you from a bad outcome — and it's the one most clients never have at the salon they booked before coming to us."
— Pooja Deveshwar, Founder, PD's Beauty Salon
FAQs
Is hair fall normal after smoothening?
Some hair fall during the first wash is normal — loose or already-shedding hair dislodged by the treatment. If significant hair fall continues beyond the first two washes, it needs professional assessment. Continued heavy shedding is a sign of damage, not a normal part of the process.
Can smoothening permanently damage hair?
Yes — if applied to hair that isn't in the right condition for it, or using low-quality products, or with incorrect processing time. Permanent cuticle damage from overprocessing is the most serious outcome and is irreversible without cutting the affected hair. This is why pre-treatment assessment matters so much.
Why is my hair so dry after smoothening?
Some dryness immediately after smoothening is normal — the chemical process strips natural oils. Extreme or persistent dryness that doesn't respond to conditioning suggests moisture barrier damage. A professional deep conditioning or protein treatment — not just home masks — is needed.
Can I get smoothening done on coloured hair?
It depends on the condition of the hair and how recently it was coloured. Lightly coloured hair in good condition can handle smoothening with proper assessment. Heavily bleached or highlighted hair usually needs a different approach — nanoplastia is almost always a safer option. Always get a strand test done before combining these treatments.
What causes uneven results after smoothening?
Uneven application, inconsistent heat during flat ironing, or sections that weren't adequately processed. This is a technique issue, not a product issue. Contact your salon within the first two weeks — it can usually be corrected while the treatment is still fresh.
How do I know if a salon is using formaldehyde-free products?
Ask directly — any reputable salon will answer without hesitation and can name the product brand they use. If the answer is vague or the price is unusually low compared to other salons in Delhi, it's worth asking specifically.
Is smoothening safe for all hair types?
No. Hair that is severely damaged, recently bleached, or has very low density needs a proper assessment before smoothening. For these hair types, nanoplastia is often the safer and more appropriate treatment. A consultation before booking is always the right starting point.
How long do smoothening side effects last?
Normal effects — mild scalp sensitivity, heaviness, temporary flatness — resolve within the first week. Anything persisting beyond two weeks — breakage, scalp irritation, uneven texture — is not a side effect but a sign of a problem that needs professional attention.