Have to admit: when this landed on our desk, we weren't sure exactly what it's supposed to do. Is it a serum? Is it a moisturiser? Described as 'a daily dose of strength for your skin', that's – well, a bit obscure, actually...

And then we tried it. And were immediately hooked. Vichy Mineral 89 is categorised as a 'booster' – but what it really feels like is a long, replenishing drink of water for skin. Actually, scanning the how-to on the back, it's designed to be used with a couple of drops at a time 'as the first step of your skincare regime' – something extra, then, to add in.

But the mega-dose of hyaluronic acid which gives this its deliciously quenching texture is definitely why it's so plumpifying and hydrating. It leaves skin really, really smooth – and then you can add whatever you like over the top: a facial oil, an SPF, a night cream.

Vichy Mineral 89 definitely comes into its own when skin's feeling parched, post-sun exposure or after a windy walk. (There've been a few of those in the last week, we can tell you.) And we think it'll also be a godsend when the central heating switches on again.

Yes, it's an extra step in your skincare regime. But the glug, plug, glug sound effect you can almost hear coming from your complexion as you apply makes it totally worth discovering.

Vichy Mineral 89/£16.02 at lookfantastic.com