A lightweight, no-rinse densifying treatment with biotin, centella asiatica, and Marine Density Infusion. It strengthens and thickens the look of hair, with heat protection up to 230°C (450°F).
A lightweight, no-rinse densifying treatment with biotin, centella asiatica, and Marine Density Infusion. It strengthens and thickens the look of hair, with heat protection up to 230°C (450°F).
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3400
$34.00
Out of stock
Long & Strong Densifying Leave-In Treatment is the finishing step in Keune’s award-winning Long & Strong routine, which won a 2026 Dutch Beauty Award in hair care. This lightweight, fast-absorbing, no-rinse treatment energizes the scalp, fortifies the hair fibre, and makes hair look and feel thicker and fuller over time.
Thicken and densify: Marine Density Infusion (dulse seaweed extract) and biotin help hair look and feel fuller and denser.
Strengthen: It fortifies strands to reduce breakage and protect the lengths and ends against split ends.
Soothe and protect: Centella asiatica provides calming antioxidant care for the scalp.
Hydrate: Shea butter, coconut oil, hyaluronic acid, and panthenol nourish and soften without weighing hair down.
Heat protection: It shields hair from styling tools up to 230°C (450°F).
It’s scalp microbiome-friendly and suitable for daily use. The formula is vegan, silicone-free, gluten-free, and cruelty-free.
After washing with Long & Strong Shampoo and Conditioner, towel-dry hair.
Apply to clean, towel-dried hair, focusing on mid-lengths and ends.
Do not rinse.
Style as desired. It protects up to 230°C (450°F) when heat styling.
Use after every wash.
For the full routine: Apply Long & Strong Super Serum to the scalp first, then the Leave-In on the lengths.
Between washes: You can apply a little to dry hair to smooth ends and reduce frizz.
All hair types and textures, especially fine, thin, fragile, or breakage-prone hair, and seasonal or postpartum shedding. It’s ideal for anyone wanting thicker, fuller-looking, stronger hair, and for those who heat-style. Safe for colour-treated hair.
Keune has been perfecting hair care since 1922. It all started with Jan Keune, a pharmacist from Amsterdam, and his fascination for curls. Today it’s one of the last family-owned professional hair care brands in the world.
Salon Professional Quality
The Style line was developed with top hair professionals and scientists, built on breakthrough formulas that set a new standard for styling. Keune Style was developed in collaboration with the top hair professionals and scientists worldwide.
Sustainability Commitment
Vegan, cruelty-free and B Corp certified. Keune is a B Corp certified family business, and the entire Style line is not tested on animals and carries the vegan quality mark, with one exception: the Restyler.
Worldwide Renown
Trusted by stylists in more than 80 countries. Keune products have been made in Amsterdam since 1922 and are distributed to more than 80 countries. A favourite of salons and hairdressers everywhere for every hair type.
