Keratin vs hair botox vs smoothening, and how long each lasts

Walk into any salon asking to "fix frizzy hair" and you'll usually be offered one of three services: keratin treatment, hair botox, or smoothening. They're often talked about as interchangeable, and the results can look similar in a photo — straighter, glossier, lower-maintenance hair. But the chemistry behind each one is different, and that difference affects how your hair feels, how long the result lasts, and what it costs you in upkeep.

Keratin treatment

Keratin treatments work by coating and partially bonding a keratin protein solution to the hair shaft, then sealing it in with heat from a flat iron. The result is hair that's noticeably smoother and takes a fraction of the time to blow-dry, because the treatment reduces the hair's natural porosity and frizz-forming swelling.

Most keratin formulas release small amounts of formaldehyde or a formaldehyde-releasing preservative during the heat-sealing step, which is why a well-ventilated salon and a stylist who follows the process properly both matter. Results typically last two to five months, fading gradually as the coating wears off with washing rather than growing out visibly at the root.

Hair botox

Despite the name, hair botox has nothing to do with the injectable cosmetic treatment — it's a marketing term for a deep conditioning treatment built around ingredients like hydrolysed keratin, collagen, vitamins and amino acids, without the formaldehyde-releasing chemistry keratin treatments use.

Instead of coating the hair shaft, hair botox works by filling in gaps in damaged strands — which is why it's often recommended for hair that's been through repeated colouring or heat styling and has lost thickness rather than simply grown frizzy. It smooths hair and reduces frizz, though usually less dramatically than keratin on very curly or coarse hair, and results tend to last two to three months.

Smoothening

Smoothening (sometimes called a "keratin smoothing" or simply "rebonding" depending on the exact formula) is the most permanent of the three. It uses stronger chemical bond-breakers to physically restructure the hair's internal bonds, straightening the strand at a structural level rather than coating or conditioning it.

That structural change is semi-permanent — it grows out rather than washes out, which means a visible line between treated and new growth appears over time, and touch-ups are usually needed every four to six months at the regrowth line rather than a full redo. It's the strongest option for very curly or unruly hair, but also the hardest on hair that's already coloured or chemically treated.

So which one should you pick?

As a rough guide: keratin treatment suits hair that's frizzy but otherwise healthy and you want a temporary, lower-commitment result. Hair botox suits hair that's more damaged or thinned from colour and heat styling, where conditioning matters as much as smoothing. And smoothening suits very curly, coarse or unruly hair where you want a longer-lasting, more dramatic straightening result and are willing to manage the regrowth line.

The honest answer usually depends on things a photo can't show — how your hair currently feels, whether it's been coloured recently, and what you actually want it to do day to day. That's a two-minute conversation, not a guess.