What's the difference between a scalp serum and a lengths serum?

Scalp serums go on the skin at the roots: Kérastase Genesis Serum Anti-Chute Fortifiant, Symbiose Sérum Nuit, Nutritive Nutri-Supplement Scalp Serum, L'Oréal Scalp Advanced Anti-Oiliness Serum and Serioxyl Advanced Density Activator. Lengths serums go through the hair itself: Première Serum Filler, Blond Absolu Hyaluronic Acid Serum, the Split Ends Serum and Chroma Thermique. Get the right one for where the problem is.

How do I use the Kérastase Genesis serum?

Part dry or towel-dried hair in sections and apply it straight to the scalp, then massage it in. No rinsing. Kérastase positions it for hair fall caused by breakage, and it works best used consistently alongside the Genesis shampoo. If you're losing a lot of hair or it's come on suddenly, see a GP first. Step by step in how to use Genesis serum.

When should I use a night serum?

Apply it to dry hair before bed and leave it in. Kérastase Nutritive 8H Magic Night Serum is for dry lengths and Blond Absolu Cicanuit is for lightened hair that feels weak or rough. Both are designed not to leave marks on your pillow. Morning hair should feel softer without you having to do anything else.

Can a serum repair split ends?

No product joins a split end back together. Kérastase Nutritive Nutri-Supplement Split Ends Serum seals and smooths the ends so they look neater and are less likely to split further, which is a real help between trims. Once the split has travelled, the only fix is scissors. Read how to deal with damaged ends.

Which serums protect against heat?

Kérastase Chroma Absolu Serum Chroma Thermique is a heat-protecting leave-in for coloured hair, applied to damp hair before the dryer. Redken's Heat Protecting Jelly Serum adds body as well as protection, which suits fine hair that drops flat. Use either on every blow-dry, not just straightener days.

Is the Symbiose night serum for dandruff?

Kérastase makes it as an intensive overnight serum for a flaky, dandruff-prone scalp, used alongside a Symbiose shampoo. Apply it to a dry scalp a few nights a week. If flaking comes with redness, soreness or doesn't improve after a few weeks, see a GP or dermatologist. More in our Symbiose guide.