Sarah K Carnival Brazilian Protein Treatment 500ml

Sarah K Carnival Brazilian Protein Treatment - 500ml is a professional, formaldehyde-free Brazilian protein smoothing treatment that reduces volume and controls frizz while treating the fibre, powered by macadamia, lactic acid, hydrolyzed collagen and silk and wheat amino acids. Made for the salon chair, it prepares hair for a sleek, aligned, naturally smooth finish and forms the heart of the Carnival system alongside its clarifying prep and pH-balancing finish.

At a glance

What it is: professional Brazilian protein smoothing treatment (volume reducer)
Core action: reduces volume, controls frizz, aligns and smooths the fibre
Hero actives: macadamia, lactic acid, hydrolyzed collagen, silk and wheat amino acids
Free from: formaldehyde
Format: 500 ml, professional use
Pairs with: Clarifying Shampoo (prep) and Universal Neutralizing (finish)
How to use: apply off the roots, 45 minutes, rinse, dry, flat-iron thin sections

Why a protein smoothing treatment

Frizz and volume come from a raised, uneven cuticle that lifts in humidity and catches the light unevenly. This treatment works inside the fibre rather than only coating it: lactic acid helps realign and rebalance the hair's surface while macadamia, collagen and amino acids replenish and soften. The result is a professional smoothing service that reduces bulk and tames frizz without the harsh fumes linked to older straightening chemistry. Because the formula is formaldehyde-free, it delivers that sleek, manageable finish with a gentler in-chair experience for stylist and client alike.

Key ingredients

Macadamia oil - rich, emollient nourishment that helps tame frizz and add slip.
Lactic acid - gently realigns and rebalances the fibre for a smoother, more aligned surface.
Hydrolyzed collagen - supports softness and body along the strand.
Silk and wheat amino acids - replenish the hair and help condition during the service.

What to expect

Expect noticeably reduced volume, softer movement and a smooth, glossy finish that feels lighter and easier to style. On wavy to lightly curly hair the look reads close to naturally straight; on curlier or coarser textures it relaxes and defrizzes while keeping some natural body. This is a progressive smoothing treatment, not a permanent straightener - results gradually soften with washing, and how long they hold depends on hair type, wash frequency and home care.

Who it is for

Professionals looking for a formaldehyde-free Brazilian protein smoothing service.
Clients with frizzy, voluminous or unruly hair who want a smoother, more manageable result.
Wavy through to very curly textures, with processing scaled to the curl.
Coloured or highlighted hair, following a strand test on lightened sections.

Who it is not for

Anyone wanting a permanent, poker-straight result - this reduces volume and frizz rather than permanently straightening.
Shoppers who need a fully vegan formula, as it contains collagen and silk and wheat amino acids.
At-home users wanting a no-heat option; it needs a full blow-dry and flat iron and is intended for professional use.
Anyone who only needs to prep or finish the service - reach for the Sarah K Clarifying Shampoo (Step 1) or Sarah K Carnival Universal Neutralizing (Step 3) instead.

Professional tip

Work in very thin sections and keep the product about a centimetre off the scalp - even distribution and clean, fine partings are what separate a sleek result from a patchy one. On coarse or very curly hair, allow the full processing time and add flat-iron passes gradually rather than turning up speed, checking a strand as you go so you dial in the exact smoothness the client wants.

How to use

Apply strand by strand through clean hair, leaving a 1 cm gap from the roots.
Leave to act for 45 minutes.
Rinse thoroughly.
Dry the hair 100%.
Flat-iron in very thin sections to seal the smoothing.

Safety: For professional use. Keep out of reach of children, and avoid contact with eyes, mouth and mucous membranes. Protect from light, excessive heat and humidity. Always carry out a strand and patch test before the service, and discontinue use if any sensitivity occurs. Follow the precautions printed on the bottle.

Using it within the Carnival system

In the salon protocol this treatment is the smoothing active at the heart of the system. Prep the hair first with Sarah K Clarifying Shampoo with Micellar Water - 1000ml to lift residue and open the cuticle, then apply this treatment and iron. To complete the service, finish with Sarah K Carnival Universal Neutralizing - 500ml, which helps rebuild the strands and rebalance pH for extra shine. The same active is also available as Sarah K Carnival Brazilian Protein Treatment - 1000ml for longer hair or higher-volume salons.

In short

Formaldehyde-free Brazilian protein smoothing that reduces volume and controls frizz.
Powered by macadamia, lactic acid, collagen and silk and wheat amino acids.
Progressive, natural-looking result - not a permanent straightener.
Professional 500 ml, and the core active of the Carnival salon system.

Complete the Carnival smoothing system

Sarah K Clarifying Shampoo with Micellar Water - 1000ml -- Step 1 prep that clears residue and readies the hair
Sarah K Carnival Universal Neutralizing - 500ml -- Step 3 finish that rebuilds and rebalances pH
Sarah K Carnival Brazilian Protein Treatment - 1000ml -- the same smoothing active in a larger size

Frequently asked questions

Does this treatment contain formaldehyde?

No. This is a formaldehyde-free Brazilian protein smoothing treatment, so it delivers a sleek, frizz-reduced finish without formaldehyde in the formula. That means a gentler in-chair experience, with none of the harsh fumes linked to older straightening chemistry. As with any professional smoothing service, work in a well-ventilated space and follow the usage and precaution steps for the best results.

Can I use it on coloured, highlighted or bleached hair?

Yes, it can be used on coloured, highlighted and bleached hair, and many clients find it leaves lightened hair looking smoother and glossier. Because bleached or highly processed sections are more fragile, always carry out a strand test first and adjust processing and flat-iron passes to the condition of the hair. If a colour service is planned, it is generally best to colour before smoothing.

How long do the results last?

This is a progressive smoothing treatment, so the effect is strongest right after the service and then softens gradually with each wash rather than stopping on a fixed date. Longevity depends on your hair type, how often you wash, whether you colour or bleach, and your home care. Washing less often and using a gentle, sulfate-free shampoo helps the smoothness hold for longer.

Is this a keratin treatment, and how is Brazilian protein different?

It is a Brazilian protein smoothing treatment rather than a classic keratin formula. It relies on macadamia, lactic acid, collagen and amino acids to smooth and nourish the fibre, and is often chosen as a formaldehyde-free alternative to traditional keratin straightening. Like those services it reduces frizz and volume, but it aims for a natural, softened result rather than a permanently poker-straight one.

Do I need the Clarifying Shampoo and Universal Neutralizing, or just this?

You can apply this treatment on its own following its own steps, but in the full Carnival protocol it sits between two partners. The Clarifying Shampoo preps the hair by clearing residue and opening the cuticle, and the Universal Neutralizing finish helps rebuild the strands and rebalance pH for extra shine. Using the complete system gives the most polished, longest-looking salon result.

How do I keep the results looking their best?

Treat it like any smoothing service: wash a little less often, ideally two to three times a week, and switch to a gentle, sulfate-free shampoo so the smoothness is not stripped away. Avoid heavy build-up, chlorine and salt water where you can, and keep everyday heat styling moderate. Regular conditioning keeps the hair soft and helps the sleek finish last.

Should I do a strand and patch test first?

Yes. Always carry out a strand test and a patch test before the full service. A strand test shows how the hair responds and how much smoothing to expect, while a patch test helps flag any sensitivity in advance. This is standard best practice for professional smoothing treatments and is especially useful on fragile, coloured or previously treated hair.

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