Kérastase Fusio-Dose: The Customised In-Salon Treatment, Explained

Fusio-Dose is Kérastase's customised in-salon treatment: the stylist mixes a concentrate with a booster, chosen for your specific concern (repair, hydration, smoothing, or shine), for fast, visible results in minutes. It's a lovely quick “results-now” boost, often added to a colour or before an event. The honest caveat is that it's temporary, typically lasting around five weeks.

What Fusio-Dose is

Fusio-Dose is the bespoke option in the conditioning world. Rather than one standard mask, the stylist picks a base concentrate aimed at your main concern and adds a booster to amplify a second benefit, then mixes and applies it for very fast uptake. The pitch is “customised and instant”: most of the visible result shows up within minutes, which is why it’s popular as a colour add-on or a pre-event pick-me-up. Your hair leaves softer, glossier, and more manageable, tuned to whatever you told the stylist was bothering you.

The honest expectations

Two things to be clear about. It's a conditioning treatment, not a structural rebuilder. If your hair has real breakage, a bond treatment like K18 or Olaplex is doing a different, deeper job. And it's temporary: results are strongest right after and generally fade over about five weeks, which is why it suits a regular re-dose rhythm rather than a one-time fix. None of that makes it a bad treatment; it just makes it a “treat and maintain” one rather than a cure.

Is it worth it?

For a fast, personalised gloss-and-soften, especially tacked onto a colour or before a big day, a lot of people find it genuinely worth it. If you're after long-term repair or your hair just needs straightforward moisture, a simpler (and cheaper) conditioning treatment may give you most of the benefit. The “customised” part is the appeal; whether you need that level of customisation depends on your hair.

Where Backstage fits

We don't currently offer Fusio-Dose. For the everyday version of what it does (softer, shinier, more manageable hair), our Hair Conditioning Treatment ($55) covers most people beautifully, and we can tailor it in the chair to whether your hair needs moisture, smoothing, or a shine boost. If your real goal is repair, we'd point you to a bond treatment instead. A quick consultation sorts out which of those you actually need, so you're not paying for customisation you won't notice.