A daily leave-in that does the work of several products: smooths the cuticle, seals split ends, adds luminous shine, detangles without effort, and provides heat protection — all in 1–3 pumps applied to towel-dried hair before styling. REF Stockholm Leave In Serum is part of the brand's premium Signature Collection, built around Organic Coconut Oil and a botanical active complex that delivers deep hydration without heaviness. The everyday essential for dry, damaged, or colour-treated hair that needs consistent care between washes, not just on treatment days.

Signature Collection Leave In Serum sits within REF Stockholm's Signature Collection alongside Shine Elixir and the Detangling Spray — a premium tier enriched with exclusive nourishing ingredients. The Signature Collection is REF Stockholm's most concentrated expression of their Nature + Science philosophy. The Leave In Serum's hero Signature Collection ingredient is Organic Coconut Oil — a penetrating emollient with proven protein-loss prevention and deep moisturising properties, particularly effective for high-porosity and textured hair types.

Mechanism Leave In Serum is a water-based, rinse-free serum — an emulsion that delivers conditioning and protective actives in a lightweight, non-greasy base that absorbs into towel-dried hair without residue.

Cetearyl Alcohol and Cetyl Alcohol form the emollient conditioning base — fatty alcohols that provide the serum's creamy texture and deliver targeted cuticle-smoothing and detangling properties. Guar Hydroxypropyltrimonium Chloride is a cationic guar that deposits at negatively charged damage points on the cuticle, providing targeted slip, combability, and anti-static frizz reduction. Cetrimonium Chloride provides additional cationic conditioning. Dimethicone delivers the surface smoothing, shine enhancement, and split-end sealing that are the most immediately visible benefits of the formula.

Cocos Nucifera (Coconut) Oil is the Signature Collection hero active — an emollient with an unusually small molecular structure that allows it to penetrate the hair shaft and prevent protein loss. REF Stockholm notes that Coconut Oil can deeply moisturise, prevent protein loss, and reduce hair damage, making it particularly effective for high-porosity hair (such as chemically processed, bleached, or textured hair) where the cuticle's gaps allow moisture to escape rapidly. Simmondsia Chinensis (Jojoba) Seed Oil closely mimics the hair's natural sebum, absorbing without residue to add elasticity and shine. Helianthus Annuus (Sunflower) Seed Extract provides UV and antioxidant protection.

Hydrolyzed Quinoa delivers the formula's protein reinforcement — the same REF Stockholm care signature seen across the range, providing amino acid and structural support at the hair surface. Sodium Methoxy PEG-16 Maleate/Styrene Sulfonate Copolymer is a protective film-forming polymer from the same chemical family as the heat-protective polymer in REF Stockholm's Heat Protection N°230 — here providing a lightweight protective surface coating that seals moisture in the shaft and shields the cuticle from environmental stress and heat damage during blow-drying. Quaternium-95 provides anti-static conditioning. Hydroxyethylcellulose contributes to the formula's silky texture and film-forming smoothness.

Glycerin and Propylene Glycol provide the formula's humectant moisture-binding — drawing water into the hair shaft and maintaining hydration throughout the day. Butylene Glycol provides additional moisture-binding and penetration support.

The formula is tinted with CI 75120 (Annatto) and CI 16035 (Red 40) — natural and synthetic orange-red pigments that give the serum its characteristic warm amber colour. These do not deposit on the hair.

Metro Vancouver note: Hard water mineral deposits create a barrier on the hair shaft that blocks leave-in products from absorbing fully — meaning a hydrating serum will underperform on hair with active mineral buildup. If results are inconsistent, a chelation step before your routine may significantly improve uptake. See our Hard Water Hair Damage hub for the protocol.

Who It's For Dry, damaged, colour-treated, bleached, or textured hair of any density. Particularly effective for high-porosity hair types — including Afro, coily, and repeatedly processed hair — where the penetrating properties of Coconut Oil directly address the moisture-loss mechanisms that other leave-ins can't reach. Apply to mid-lengths and ends only; avoid roots on fine hair to prevent over-softening.

Note: for frizzy hair without underlying dryness or damage, the Shine Elixir or Heat Protection N°230 may be more appropriate — the Leave In Serum's primary benefit is deep hydration and repair rather than frizz control specifically.

Key Ingredients

• Cocos Nucifera (Organic Coconut) Oil — Signature Collection hero; penetrates the hair shaft to prevent protein loss, deeply moisturise, and reduce damage — particularly effective for high-porosity hair
• Simmondsia Chinensis (Jojoba) Seed Oil — Sebum-mimicking emollient; adds elasticity and shine without residue
• Sodium Methoxy PEG-16 Maleate/Styrene Sulfonate Copolymer — Protective film-forming polymer; seals moisture in the shaft and provides heat protection during blow-drying
• Dimethicone — Surface smoothing and shine; seals split ends and adds cuticle reflectivity
• Hydrolyzed Quinoa — Protein and amino acid reinforcement at the hair surface; builds structural resilience
• Guar Hydroxypropyltrimonium Chloride — Cationic guar; targeted cuticle smoothing, detangling, and anti-static conditioning
• Glycerin — Humectant; draws and retains moisture throughout the day

How to Use Apply 1–3 pumps to towel-dried hair from mid-lengths to ends. Do not rinse. Style and blow-dry as desired, or air-dry. Adjust amount based on hair length and density: 1 pump for fine or short hair, 2–3 pumps for medium to long or thick hair.