So, the short answer is that keratin treatment is the umbrella term that covers any salon smoothing treatment in which the hair is treated with keratin products and sealed in using heat. One of these brands and styles is called "Brazilian Blowout" and generally it's lighter on the straightening and faster to apply. Neither is automatically safer. What matters most is the formula, and in particular whether it contains or releases formaldehyde. They're always seen as rivals in conversation. Mostly they aren't. A Brazilian blowout is a type of keratin smoothing procedure, so the question is which type is right for your tresses and what's inside the bottle.
Are they the same thing?
More or less, except for the names. Keratin Treatment" is a category. It ranges from a little smoothing to a almost-poker-straight finish. "Brazilian Blowout" started as a particular brand and turned into a catch-all, the way people say "hoover". It's commonly marketed in the UK as a "Brazilian blow dry".
Whatever the case, it is the same process. A stylist works product through hair, blow dries and seals with a flat iron. You come out with smooth, shiny, less frizzy locks that last for several months.
The quick comparison
| Keratin treatment | Brazilian blowout / blow dry | |
|---|---|---|
| What it is | The broad category | A specific style and brand of smoothing |
| Finish | Smoother, often straighter | Smooth, with more natural movement |
| How long it lasts | About 3 to 5 months (sources say 3 to 6) | About 6 to 12 weeks (some say up to 3 or 4 months) |
| Time in the chair | Often 2 to 3 hours | Often quicker |
| Washing afterwards | Traditionally you wait around 72 hours | Often allowed sooner, depending on the product |
| Suits | Very frizzy or unruly hair | Hair that needs smoothing but should still move |
Consider those as ballparks. There is a lot of disagreement between salon pages. One claims that keratin lasts for 3 to 6 months, while another states that it lasts for 3 to 5 months. One provides 8-12 weeks blowout for Brazilian, another 6-12 weeks. Your type of hair and treatment of it make all the difference.
The formaldehyde bit
This is the part worth slowing down for, because it's the most important difference between treatments and the label doesn't always tell you.
The majority of traditional smoothing formulas have depended on the use of formaldehyde or its release when subjected to high heat from a blow-dryer and flat iron. The common one is methylene glycol. It's formaldehyde dissolved in water, and it behaves the same way when it's hot.
This record is fairly transparent. OSHA, the U.S. workplace safety agency, conducted tests on some smoothing products in 2011 (some of which were marketed as "formaldehyde free") and found formaldehyde in them. According to one study, Brazilian Blowout's Acai solution contains approximately 11.5%. The US FDA has issued the company a warning letter for claiming its product is formaldehyde free, and OSHA has detected excessive exposure to formaldehyde by stylists in some salons.
Since then, brands have been reformulated, and many others are available that contain different active ingredients like glyoxylic acid or amino-acid systems. The word formaldehyde-free is not a guarantee - it is a claim. Whilst cosmetics are regulated in the UK (and salons are supposed to use regulated products), not all treatments are low risk.
So ask. Which product and brand do they use? Can you see the ingredient list and the Safety Data Sheet? (Professionals have one.) Check it for formaldehyde, formalin, methylene glycol and anything else that releases formaldehyde. Ask how the room's ventilated, because the fumes from heating are a real concern for you and the stylist. If the answer is vague, or "it's natural", walk away.
Is it safe?
For healthy adults, a modern formaldehyde-free treatment from a trained stylist in a well-ventilated salon is generally thought reasonably safe by the salon sources we checked. Formaldehyde is the main risk, and it's linked to irritation of the eyes, nose, throat and scalp. It's also classed as a human carcinogen.
Heat can hurt hair that's already fragile, bleached or breaking. If you're pregnant or breastfeeding, some salon guides advise skipping smoothing treatments, so check with your GP or midwife. Don't have one if your scalp's inflamed or irritated. A strand test is a sensible first step, and a salon that insists on one is usually a good sign.
So which one?
Go for keratin if your hair's very frizzy, curly or stubborn, you want the longest-lasting and smoothest finish, and you don't mind a longer appointment and stricter aftercare. Go for a Brazilian blow dry if you want smoother hair that still has bounce, you'd rather have less downtime, and you're fine with results fading sooner. Think twice about either if your hair is badly damaged, you're pregnant or breastfeeding, or the salon can't tell you what's in the product.
Aftercare
It depends on the product, so ask your stylist first. Common advice is to keep your hair dry for however long they recommend (traditionally up to 72 hours for keratin), avoid tight bands and clips that crease the hair, switch to a sulphate-free shampoo, and use heat protection. One guide suggests not repeating the treatment more than around three times a year, but ask your stylist what's right for you.
What it costs
Prices swing so much by city, salon and hair length that a single number would mislead you. Get a written quote, ask what's included, and compare more than one salon. A price far below the rest should make you ask why. The product might be cheaper for a reason.
Frequently asked questions
What is the difference between a Brazilian blowout and a keratin treatment?
Keratin treatment is the broad category of keratin-based smoothing services. A Brazilian blowout is a specific brand and style within it, usually giving a smoother but less poker-straight finish and often lasting a shorter time.
Which lasts longer, a Brazilian blowout or a keratin treatment?
Keratin treatments are usually reported to last longer, roughly 3 to 5 months, while Brazilian blowouts tend to last around 6 to 12 weeks. Results vary by product and aftercare.
Do Brazilian blowouts and keratin treatments contain formaldehyde?
Some do, or they contain ingredients that release formaldehyde when heated. Many newer formulas avoid it, but you should ask for the ingredient list and the Safety Data Sheet.
Is a Brazilian blowout bad for your hair?
It can be hard on already damaged hair, and heat is a factor. On healthy hair, done by a trained stylist with a suitable product, many people see few problems. Ask for a strand test if you're unsure.
What is a Brazilian blow dry in the UK?
It's the UK name for a Brazilian blowout style keratin smoothing treatment.
Sources and further reading
- OSHA: Hair salons, facts about formaldehyde in hair products
- OSHA: Hair smoothing products that could release formaldehyde
- Wikipedia: Brazilian hair straightening
- Salonory: Keratin treatments vs Brazilian blowouts, a stylist's guide
- OK Beauty Hair: Brazilian blowout vs keratin
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