Kérastase began in Paris in 1964, founded by François Dalle, who was then running L'Oréal. The launch was a big idea for its time: the first professional comprehensive haircare products, including the first bain, which is the French word for shampoo, and the first scalp care. The brand has kept that habit of firsts. Bain Divalent arrived in 1973, the first care mask in 1979, and the Nutritive range in 1984. The Nutritive 8H Magic Night Hair Serum for Dry Hair and the Nutritive Bain Satin Riche Shampoo come from that family. The oil that became the brand's most famous product is Elixir Ultime, and the refillable hydrating version here shares space with the Blond Absolu Cicagloss oil, the Chroma Absolu L'Huile Chroma Éclat and the Chronologiste L'Huile de Parfum. Gloss Absolu fills out the wash day with a Hydra-Illuminating Shampoo, a Hydra-Glaze Hair Mask and Insta Glaze and anti-frizz conditioners, while Genesis offers shampoos and conditioners for hair that feels weakened. For the pairing question, I like this guide to shampoo and conditioner pairs by hair type, and it sits well next to the hair oil shelf.

The second group is the leave-in side of the brand, and it echoes another Kérastase first. In 1989 the house introduced a hair care serum for dry lengths, and serums have been a signature ever since. The Genesis Anti Hair-Fall Fortifying Serum, the Chronologiste Overnight Youth Serum and the Chronologiste Longevity Potion Serum are the treatment picks. Première Repairing Anti-Frizz Filler Serum and Gloss Absolu Frizz-Glaze Cream handle the smoothing, and Huile Sublime Repair Oil covers the ends. The Resistance Extentioniste Thermique Blow-Dry Cream and the Genesis Heat Protecting Leave-In Treatment are the ones to reach for before a hair dryer. What I would skip is putting a rich cream and an oil on fine, flat roots on the same day; keep either one from the mid lengths down. For the smoothing step, a keratin shampoo guide shows what pairs with a serum.

This last group is the lighter, more playful side of the brand. The Gloss Absolu Hair Perfume with citrus, vanilla and rose follows the idea of a hair perfume that scents the lengths without the weight of a full oil. For heat styling there are the Genesis Defence Thermique Fortifying Spray, the Nectar Thermique Blow-Dry Milk and the Discipline Anti-Frizz Smoothing Spray. Blonde Absolu Blonde Guard Hydrating Wonder Shield and the Chroma Absolu Gloss serve color, and the Ker Res and Ker Specifique bains are the shorter named shampoos. The gift sets are a good way to meet the brand: the Elixir Ultime and 8H Magic mini duo, the Première Bonding Discovery set and the Gloss Absolu and Genesis trios. They are small, easy to give and each one carries a full routine in miniature.

The brand now sells in more than 60 countries and works with over 150,000 hairdressers, and that salon history still runs through the whole line. My routine would begin with a Genesis or Gloss Absolu shampoo, add an Elixir Ultime oil on the ends, and finish with a heat protecting spray. If your hair is dry, take a look at these conditioners for dry hair, then come back and choose the Nutritive serum.

To round out the look, see Living Proof Hair Care and Scalp Serums for Hair Density.