Keratin Hair Treatment: The Honest Chat I Wish Someone Had Given Me Before I Booked Mine

The most obvious thing we can say about keratin hair treatments is that they're full of keratin – which is the protein our hair is mainly made from. You see, when you get this treatment done at the salon, it involves coating your hair with a keratin-based formula then sealing it using heat (typically a flat iron). That's what smoothes out all the hairs, flattening their cuticles as well as killing off all the frizz and making your locks look glassy.

A keratin hair smoothing treatment isn't going to be permanently altering the texture of your hair because it doesn't act like a relaxer. Instead, its effects are semi-permanent, fading away gradually after a period of time ranging between 3-5 months (depending on the particular formula used and other factors including your hair type and care routines) before eventually disappearing altogether. If anyone says that a keratin hair smoothing treatment will last forever, chances are high that they're trying to sell you something.

Here's the straight version. It reduces frizz and smooths. It does not add volume. In the first few weeks hair can feel sleeker and flatter, so if your whole personality is a big bouncy blow-dry, think twice.

It also doesn't repair damage in any lasting way. It's a coating, so the benefits keratin for hair treatment are mostly about how hair looks and behaves:

• Far less frizz, even in humidity
• Shorter blow-dry times
• A glossier, smoother finish
• Easier detangling

Lovely, but cosmetic. Keep that in mind for the next bit.

First up – formaldehyde. This is probably familiar to most people in some form (although there might be some details missing). Many formulas include formaldehyde, or other ingredients that emit formaldehyde into the air as a gas when exposed to heat from a flat iron.

Formaldehyde is a well-known irritant, but becomes a recognized carcinogen at higher levels of exposure. Regulators are starting to take note of this on salons, and raising flags over its presence in salon products. However, don't think a 'formaldehyde free' label guarantees that no amount of it will be released.

Again, don't panic here, just ask...

• Ask your stylist which product they're using and what's in it?
• Make sure that you are booked in somewhere well ventilated – let them know if the fumes bother you.
• Do a patch test if you have reactive skin/scalp.
• Check with your doctor if you're pregnant/ breastfeeding/asthmatic before using.

Of course most people will just sail through this part but here are some of the common ones we found worth noting.

• Hair feels dry: which means your hair could be feeling stiff/straw like due to either being overdone with product or the amount of heat you used on it
• Breakage: This tends to occur when you have bleached/fragile hair or perhaps the heat from your iron was too intense for what your hair can take
• Scalp irritation: itching, redness or a stinging scalp
• Eye, Nose & Throat Irritation: during treatment itself
• Allergic reactions: rare, but they happen

So in the long-term, while this treatment might help tame some frizz, there's nothing about these services which support long-term health benefits to your locks.

This is the part salons mumble, and it's what decides whether you get four glossy months or four crispy weeks.

• Follow your stylist's wash timeline. Commonly it's two to three days before your first wash, but formulas differ.
• Don't tie it up. No ponytails, clips, headbands or tucking behind the ears in the early days, or you'll set a crease into your hair.
• Go sulphate-free. Sulphates strip the coating faster, so check the label before you wash.
• Limit heat. Use a heat protectant, keep tools on a moderate setting, and don't iron every day.
• Keep it away from salt and chlorine at the beginning.

Treatment day is just the start. The real work is at home, and it's where a good routine earns its keep. If you want the long version on choosing a shampoo, I've gone deeper in our keratin shampoo guide.

• The core step: Nexxus Promend Repair Keratinizing Shampoo and Treatment Mask. If I could only buy two things, it'd be this pair. Use the shampoo for your regular washes and the Keratinizing Treatment Mask weekly, as a keratin hair mask treatment to keep hair feeling conditioned and soft between salon visits.
• The alternative: Tresemme Keratin Smooth Shampoo. A more everyday, easy-to-find option if you want a keratin-smoothing wash without committing to a full system.
• For sensitive scalps: Love Beauty & Planet Pentavitin & Hibiscus Shampoo. If your scalp felt tender or itchy after the treatment, this is the one I'd reach for, as a gentler-feeling wash while things settle.

One habit worth building: read the label on anything you use post-treatment, and ask your stylist whether it suits your specific formula.

If frizz is your daily battle and you're happy with smooth over voluminous, a keratin hair treatment can be a genuine sanity-saver. Go in with realistic expectations: semi-permanent, no extra volume, and a real commitment to aftercare. Ask the safety questions, choose a salon you trust, and treat it as a styling service, not a hair-repair plan.