ALSO KNOWN AS

Brazilian keratin treatment (BKT), keratin smoothing, keratin blow dry, permanent blow dry (UK), escova de queratina, banho de queratina — and in Brazil, simply "progressiva".

QUICK ANSWER

A keratin treatment is a semi-permanent smoothing service that coats and fills the hair with keratin protein, sealed in with a flat iron. It eliminates frizz, adds shine and loosens curl for three to five months, washing out gradually with no regrowth line. It smooths rather than straightens completely.

SCORECARD

Straightening power 6/10 (loosens curl by about half, not pin-straight). Frizz elimination 9/10. Damage risk 4/10 with modern formol-free systems, 6/10 with classic aldehyde systems. Longevity 7/10 (3-5 months). Upkeep 5/10.

HISTORY AND ORIGIN

Keratin smoothing was born in Brazil in the early 2000s, growing out of the escova progressiva culture of Rio and Sao Paulo. The idea: replace the harsh bond-breaking chemistry of relaxers with a protein coating locked in by heat. It crossed to the USA around 2005-2008, where the brand Brazilian Blowout made the category famous — then infamous, when 2010-2011 testing found formaldehyde in "formaldehyde-free" formulas. That scandal split the market into classic aldehyde systems and the acid-based, formol-free generation that dominates today. Read the full origin story on our escova progressiva page.

POPULAR YEARS

2003-2007 Brazilian domestic boom. 2007-2012 global explosion. 2012-2019 formol-free reformulation wave. 2015-today still the world's best-known smoothing service, now overlapping with nanoplastia and acid systems.

NAMES IN 20 COUNTRIES

English (UK/US) — keratin treatment / keratin blow dry / permanent blow dry. Portuguese (Brazil) — tratamento de queratina; everyday word: progressiva. Spanish — tratamiento de keratina / alisado de keratina. French — lissage a la keratine / lissage bresilien. German — Keratin-Glaettung. Italian — trattamento alla cheratina / lisciatura brasiliana. Hungarian — keratinos hajegyenesites / brazil keratin. Polish — keratynowe prostowanie wlosow. Russian — keratinovoe vypryamlenie. Turkish — keratin bakimi / Brezilya fonu. Arabic (Egypt/Gulf) — brotein / keratin. Hebrew — hachlakat keratin. Greek — therapeia keratinis. Dutch — keratine behandeling. Japanese — kerachin toritomento. Korean — keratin teuriteumeonteu. Chinese — jiaodanbai huli. Hindi — keratin treatment. Thai — keratin. Vietnamese — phuc hoi keratin. Indonesian — smoothing keratin.

CHEMISTRY — WHAT IS ACTUALLY IN IT

Two generations. Classic aldehyde systems: hydrolysed keratin plus formaldehyde or methylene glycol, cross-linked onto the hair under flat-iron heat — effective, controversial, heavily restricted. Modern acid systems: glyoxylic acid and derivatives, or carbocysteine — lower fume risk, softer result, shorter lifespan. Unlike relaxers or Japanese straightening, keratin does not permanently break disulphide bonds, which is why it fades out instead of growing out.

REGULATORY NOTE: Brazil's ANVISA bans formol as a straightening active and, since its 2025 alert, glyoxylic acid too. The US FDA's proposed formaldehyde ban (2023) remains stalled. Ask what is in the bottle.

LABEL DECODER — HIDDEN FORMALDEHYDE NAMES

If the ingredient list or safety sheet shows any of these, it is a formaldehyde-releasing system: formalin, methylene glycol, methanal, formic aldehyde, oxomethane, oxymethylene, morbicid acid. Related aldehydes to know: glutaraldehyde, glyoxal. "Formaldehyde-free" on the front label means nothing until the back label agrees.

WHAT HAIR TYPE IS IT FOR

Best for: frizzy, wavy to loosely curly hair (2A-3B); coloured or highlighted hair needing frizz control; humidity sufferers; anyone wanting manageability without pin-straight commitment. Works with care: bleached and fragile hair (strand test — the protein top-up can genuinely help); tighter curls 3C-4A wanting frizz reduction rather than straightness. Not for: anyone expecting bone-straight permanent results (see Japanese straightening); irritated or broken scalp.

EDITOR NOTE: ZOLTAN CHAIR NOTE: 2-3 lines on who you say no to

PREGNANCY AND BREASTFEEDING

Aldehyde-based systems are widely advised against during pregnancy and breastfeeding, and many salons decline keratin services in the first trimester regardless of formula. Even with formol-free systems, the sensible route is: check the exact product, and clear it with your midwife or doctor first. This is one service where waiting a few months costs nothing.

MEN AND MINIMUM AGE

Keratin works identically on men — short hair means faster appointments and lower product use, but frequent cutting removes the treated hair sooner. For minors: most reputable salons set a minimum around 16 and decline younger clients; developing hair and scalps plus strong chemistry is a poor mix.

COMPATIBILITY WITH PREVIOUS CHEMISTRY

Over colour: yes — colour first (same day, colour before keratin) or wait about two weeks after. Over bleach: usually yes with a strand test and reduced iron temperature. Over henna: often declined — henna coatings and metallic salts react unpredictably; strand test is non-negotiable. Over relaxer or old straightening: generally yes as a refresher on the lengths, applied by someone who knows what they are layering onto.

HOW TO PREPARE

Colour beforehand, not after. Arrive with dry, product-light hair (the salon clarifies anyway). Wear a collarless top — the iron works close to the neckline. Book one to two weeks before a big event, not the day before. On classic formulas, plan around the 72-hour no-wash window: no gym, no rain plans, no updos.

STEP BY STEP IN THE CHAIR

1. Clarifying shampoo once or twice — opens the cuticle, strips buildup. No conditioner.

2. Rough blow-dry to about 80 percent.

3. Product applied section by section, half a centimetre off the root.

4. Processing 20-30 minutes.

5. Full blow-dry.

6. Flat iron at up to 230 C in fine sections — the sealing step, and the most skill-dependent.

7. Depending on formula: rinse and mask same day, or (classic systems) first wash after 72 hours.

8. Style. Chair time 2-4 hours by length and density.

EDITOR NOTE: PHOTO: mid-process] [VIDEO: ironing pass

RESULTS AND LONGEVITY

Up to about 90 percent frizz reduction, curl loosened by roughly half, glass-like shine. Lasts 3-5 months and fades evenly — no regrowth line, no lock-in. Safe to repeat two to three times a year.

EDITOR NOTE: GALLERY: before and after by hair type — 2A wave, 2C-3A curl, 3B curl, coloured and highlighted, bleached blonde

MANUFACTURERS AND BRAND NAMES YOU WILL SEE

Brazilian Blowout, Keratin Complex (Coppola), Cadiveu Brasil Cacau, GK Hair (Juvexin), Cocochoco, Goldwell Kerasilk, KeraStraight, QOD, Honma Tokyo, Inoar G.Hair. On many menus the brand name IS the treatment name — see the Brazilian Blowout story.

AT-HOME KITS VS SALON

Home "keratin" kits are essentially rich protein glosses: they smooth for two to six weeks and are excellent maintenance between salon visits. What they cannot do is safely replicate a 230-degree sealing pass in fine sections — that is where home attempts go wrong, from patchy results to genuine heat damage. Honest rule: kits for upkeep, salon for the transformation.

HOME CARE — MAKING IT LAST

Sulfate-free AND sodium-chloride-free washing only — salt dissolves the coating fastest. Classic formulas: the famous 72-hour rules (no washing, ties, clips, tucking behind ears). Heat protection every styling session. Weekly keratin-boost mask. Sleep on silk if you can.

EDITOR NOTE: PRODUCT SLOT — aftercare range] [EMAIL CAPTURE — free keratin aftercare PDF

CLIMATE PERFORMANCE

Hard-water cities (London): mineral buildup dulls the coating and shortens its life — add a gentle chelating wash monthly. Hot, humid or beach climates (Hurghada, holidays): humidity resistance is keratin's superpower, but sea salt, chlorine and strong sun accelerate fade — saturate hair with fresh water before swimming, rinse straight after, mask weekly. Unprotected daily swimming can halve the lifespan.

WHAT CAN GO WRONG

Over-application: flat, greasy-looking hair for weeks. Iron too hot on bleached hair: gummy texture and breakage — the true story behind most "keratin ruined my hair" posts is heat damage, not protein. Toner shift: warm tones creeping into blondes. Sensitivity: fumes and scalp irritation with aldehyde systems. Fixing a bad result: clarifying washes speed removal, bond-repair treatments rebuild, and a good cut removes the worst. Red flags before you book: a salon that cannot name the brand and chemistry, no visible ventilation, one price for every hair type.

COMPARED TO

Japanese straightening — permanent, bone straight, regrowth line, bigger commitment. Nanoplastia — marketed as the clean successor; overlapping acid chemistry, stronger straightening claim. Hair botox — repair and volume reduction, minimal straightening.

THE HAIRDRESSER'S VERDICT

EDITOR NOTE: ZOLTAN — 4-6 sentences: what you tell clients considering keratin, what you see walk into your chair after bad ones, the one thing nobody expects.

FAQ

Q: How long does a keratin treatment last?

A: Three to five months for most hair, fading gradually rather than growing out. Lifespan depends on wash frequency, water hardness, salt and chlorine exposure, and sulfate-free, salt-free aftercare. With the right routine most clients comfortably reach the four-month mark.

Q: Can I wash my hair straight after?

A: With modern acid-based formulas, usually the same or next day — your stylist confirms which system was used. Classic formulas need the full 72-hour wait, with no ties, clips or tucking behind the ears, because the coating is still curing.

Q: Will my hair be completely straight?

A: No — keratin smooths and de-frizzes rather than straightens. Expect your curl pattern loosened by around half and blow-dry time cut dramatically. For permanently pin-straight hair you want Japanese straightening or rebonding instead.

Q: Is keratin treatment safe?

A: Modern formol-free systems applied in a ventilated salon are considered low risk for most people. The safety debate concerns formaldehyde-releasing formulas, which Brazil bans outright and the US FDA has proposed banning. Ask which system your salon uses — a good one answers instantly.

Q: Can I colour my hair as well?

A: Yes — colour first, ideally same day before the keratin, or wait about two weeks after. The treatment can soften toners slightly, so warn your colourist. Highlights and keratin pair beautifully because the protein smooths bleached lengths.

Q: Can I tie my hair up?

A: After the first wash, yes. During the 72-hour window on classic formulas, no — bands and clips leave permanent dents in the curing coating. Modern acid systems often allow a loose tie the same evening.

Q: Does it work on bleached hair?

A: Usually yes, often beautifully — porous bleached hair drinks up protein. Porosity also means faster processing, so a strand test is essential and iron temperature comes down. Severely compromised hair should be rebuilt with bond care first.

Q: Can I swim on holiday with it?

A: Yes, with protection: soak hair in fresh water before the pool or sea, rinse immediately after, and mask weekly. Salt and chlorine are the fastest ways to strip keratin — unprotected daily swimming can halve its lifespan.