Hair Smoothening vs Keratin Treatment: What’s Safer, Stronger & Smarter?
I’ve been in the beauty game long enough to say this: if I had a rupee for every time someone asked me, “Is keratin better than smoothening?” — I’d have retired to the hills of Himachal, sipping paraben-free chai.
Let’s clear the confusion. These two are not interchangeable. They’re not twins. They’re not even cousins. They’re distant exes who show up at the same salon party and pretend to be besties. But under the surface? Totally different energy.
This blog breaks it all down: what each treatment is, how it works, who should go for what, and what dermatologists, hairstylists, and scientific journals are saying about it now.
1. What’s What: Smoothening vs Keratin
Hair Smoothening is what you get when your hair just won’t behave and you’ve had it. It’s a chemical relaxer treatment — like putting your hair through therapy, but with harsh words. The process breaks down the disulfide bonds in your strands and reshapes them to lie flatter and straighter. Salons might pitch it to you as rebonding, Japanese straightening, or soft smoothening — same vibe, slightly different chemical cocktails.
Keratin Treatment, meanwhile, doesn’t mess with your hair’s inner architecture. Instead, it adds a glossy protein shield — keratin — that fills in the damaged spots and wraps your strands in a smooth, shiny coat. Sounds healing, right? Kinda is. Except, pollution, heat tools, and bleach mean most of us have barely any natural keratin left.
And yes, some treatments do mix methods — a little structure shift, a little protein patch-up. But the core difference?
Smoothening = straightening with chemicals.
Keratin = smoothing with proteins and heat.
2. The Process: What Actually Happens in That Chair
Hair Smoothening Process:
Your hair is washed and dried — no magic here.
A cream with thioglycolates is applied to start breaking the bonds.
After 30–40 minutes, your hair is ironed flatter than your hopes on a humid day.
A neutralizer locks in the new shape.
You get a final rinse and a shiny serum finish.
Keratin Treatment Process:
First, your hair gets a deep cleanse with clarifying shampoo.
Then comes the keratin-rich potion, applied on damp strands.
The blow dryer makes a comeback, followed by a flat iron set to 230°C (yes, that hot).
And then you wait. No washing for 2–3 days unless you’re using one of the newer same-day formulas.
TL;DR: Smoothening rebuilds your hair from the inside. Keratin coats it from the outside.
3. What Each One Does Best
Hair Smoothening:
Gets your hair super straight — we’re talking geometry-class-straight.
Smooth and shiny, but can look a little flat or limp if overdone.
Great if your hair is wild, curly, coarse, or just constantly frizzy.
Keratin Treatment:
Tames frizz, smooths texture, adds a silky bounce.
Doesn’t wipe out your curl pattern unless it’s already loose.
Ideal for dry, processed, or color-damaged hair that needs rehab.
👉 If your dream is hair that dries straight with zero effort? Go smoothening.
👉 If you want to look polished but still keep your natural vibe? Keratin is your low-key bestie.
4. The Risks: Let’s Get Real
Let’s not pretend these treatments are all fairy dust and good hair days. Here's the gritty side:
☠️ Chemical Exposure
Smoothening uses strong stuff — ammonium thioglycolate, sodium hydroxide — that literally restructures your hair. One wrong move, and you’re dealing with breakage or burns.
Keratin? Tricky too. The OG Brazilian blowouts often contain formaldehyde or its sneaky cousins (like methylene glycol). These are known for causing eye irritation, breathing issues, and worse — yes, even cancer risks. And no, “formaldehyde-free” doesn’t always mean safe — heat can turn those “harmless” ingredients into toxic fumes.
🧪 According to a 2024 Tel Aviv study, glyoxylic acid (found in many “organic” keratin kits) caused kidney and mucosal toxicity in lab animals. So… maybe not so clean after all.
💥 Hair Damage
- Smoothening, when done repeatedly, weakens the internal hair structure. Breakage, split ends, and thinning are common after 2–3 rounds.
- Keratin isn’t innocent either. It involves high heat, and over time, can lead to protein overload or heat-damaged cuticles.
5. What the Reports Say
The science world is buzzing, and here’s what’s fresh:
Dermatology Times (2025) says don’t trust that “formaldehyde-free” sticker without checking the fine print. Heat can still release harmful gases.
LiveScience (2024) covered findings from Israeli clinics warning about glyoxylic acid toxicity — and this one’s popping up everywhere in keratin kits now.
TOI Beauty (India, 2025) did a full-on compare of keratin, smoothening, nanoplastia, and hair botox — and found that while keratin still dominates salons, younger clients are shifting toward botox and nanoplastia for safety.
The Center for Research on Women’s Health reminded everyone that even with ventilation, formaldehyde exposure over time poses serious health risks.
6. Cost, Longevity & Maintenance
Keratin fades out naturally. Smoothening grows out, so you’ll get dual-texture roots in a few months (yep, not fun).
7. What Hair Types Suit Each Treatment?
Choose Smoothening if:
- You want poker-straight hair.
- Your curls are coarse, tight, or extremely frizzy.
- You’re okay with chemical commitment.
Choose Keratin if:
- You want to keep your natural waves but ditch the frizz.
- You use heat tools often and need protection.
- Your hair is chemically colored or bleached and needs strengthening.
For sensitive scalps or those with health concerns, consider protein-rich deep conditioning treatments, botox treatments, or nanoplastia (less harsh alternatives trending in 2025).
8. Safety Tips Before You Book
Ask for the actual ingredient list — not the glossy “natural” sales pitch.
Make sure the salon is ventilated. Like, really ventilated.
Don’t double-book your hair with back-to-back treatments. Space things out.
Always do a patch test — even if your scalp has been fine in the past.
Skip keratin if you’re pregnant or have asthma. Not worth the gamble.
9. What Experts Are Saying
“We’re seeing more scalp sensitivity and long-term damage due to poorly regulated keratin products,” says Dr. Neha Rathi, dermatologist, Delhi.
“In India, ‘keratin’ is often used as a marketing term for everything from conditioning masks to full-on chemical peels. Clients need clarity and better regulation,” adds hairstylist Anil Kapoor (not the actor 😅), salon trainer in Gurgaon.
Conclusion: So, What’s the Verdict?
There’s no one-size-fits-all solution.
Hair Smoothening is for those who want low-maintenance, always-straight strands and don’t mind a little commitment (and risk).
Keratin is more forgiving — it smooths, nourishes, and lets your natural texture live — but don’t let the “protein” label fool you. It can still come with hidden toxins.
Whatever you choose, choose with knowledge. Read labels, ask questions, and don’t fall for salon buzzwords. Glossy hair is great — but healthy hair is everything.