Sérum Universel is the everyday leave-in of Kérastase’s Chronologiste range, presented as fine pearls suspended in a clear serum. It is designed to be used on the scalp as well as the lengths, which is unusual for a serum and part of why it became a salon favourite.

The formula combines abyssine and vitamin E with hyaluronic acid to soften and hydrate, leaving hair looking glossier and behaving better in humidity. Frizz is calmed without any weight.

It carries the signature Chronologiste fragrance of tea rose, light woods and musk. Note that this presentation has been discontinued by Kérastase, so stock is limited.

Apply two or three pumps to a wet, damp or dry scalp and through the lengths. Massage in and leave — do not rinse. Style as usual.