Ingredient spotlight
Crosilkquat.
A silk-derived conditioning agent that bonds directly to damaged hair. Improves softness, texture, and manageability at remarkably low concentrations. One of the reasons QIQI aftercare leaves your hair feeling like silk.
The ingredient
What is crosilkquat?
Crosilkquat is a conditioning agent made from silk. Developed by Croda — one of the world's leading speciality chemical companies — it is built from real silk amino acids that have been given a positive electrical charge through a process called quaternization.
In plain terms: it is liquid silk protein that has been engineered to stick to your hair. When you apply a product containing crosilkquat, the ingredient seeks out and bonds to the areas of your hair that need the most help — the dry, rough, and damaged sections.
What makes crosilkquat unusual is how little you need. It works at very low concentrations, which means it conditions effectively without leaving any heavy, coated, or greasy feeling. Your hair feels genuinely softer and smoother — not weighed down.
Softness
Improved
Texture
Smoother
Manageability
Enhanced
Concentration needed
Very low
The science
How crosilkquat works.
Your hair naturally carries a slight negative electrical charge — especially when it is damaged, chemically treated, or has high porosity. Washing, colouring, heat styling, and environmental exposure all increase this negative charge by stripping away the hair's protective outer layer.
Crosilkquat carries a positive charge. When it comes into contact with your hair, opposite charges attract — and the silk amino acids bond directly to the hair shaft. This is not a surface coating. It is a genuine electrostatic bond between the ingredient and your hair fibre.
Because damaged areas carry the strongest negative charge, crosilkquat naturally concentrates where your hair needs the most repair. The most porous, roughened sections of the cuticle attract the most crosilkquat molecules. The result is targeted conditioning — smoother texture, reduced friction between strands, less tangling, and a visible improvement in shine.
This is fundamentally different from silicone-based conditioners, which coat the entire hair strand uniformly regardless of damage level. Crosilkquat is selective. It goes where it is needed and stays there.
Why it matters
Crosilkquat benefits for hair.
Instant softness
Silk amino acids smooth the cuticle on contact. Hair feels noticeably softer after a single application — not coated or heavy, but genuinely silkier to the touch.
Targeted repair
The positive charge means crosilkquat bonds preferentially to the most damaged areas of your hair. The worse the damage, the more it concentrates there. This makes it especially effective for porous, chemically treated, or heat-damaged hair.
Improved manageability
By reducing friction between individual hair strands, crosilkquat makes hair significantly easier to detangle, comb, and style. Less snagging during brushing means less breakage over time.
Lightweight conditioning
Unlike heavier conditioning agents, crosilkquat works at very low concentrations. This means no buildup, no greasiness, and no need for clarifying washes to strip residue. It conditions without compromise.
Enhanced shine
When the hair cuticle lies flat and smooth, light reflects evenly along the strand. Crosilkquat achieves this by filling in the rough, lifted areas of the cuticle — delivering visible shine that comes from genuine hair health, not a reflective coating.
Extends treatment results
For keratin-treated hair, maintaining the cuticle is everything. Crosilkquat helps preserve that smooth, sealed surface between treatments — extending the life of your QIQI Hair Controller results.
Products with crosilkquat
QIQI aftercare with crosilkquat.
Crosilkquat is a key ingredient in the QIQI aftercare range. These products are specifically formulated to maintain and extend the results of your QIQI Hair Controller treatment — and crosilkquat is one of the reasons they work so well.
From £44 · 75ml / 300ml / 1000ml
Smooth Service Shampoo
Sulfate-free keratin aftercare shampoo formulated to extend QIQI Hair Controller results. Deeply moisturising with 19 precision-selected ingredients. Prolongs smoothing treatment longevity by weeks. 95% felt nourished and smoother after one wash.
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From £45 · 300ml
Hydration Fixation Conditioner
Sulfate-free keratin aftercare conditioner that detangles, hydrates, and locks in moisture. Extends the life of your QIQI Hair Controller treatment by weeks. 97% experienced hydrated, smoother hair after first use.
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From £59 · 75g / 250g / 350g / 1kg
Super Soaker Smoothing Masque
Deep-conditioning keratin aftercare masque for intense hydration between smoothing treatments. Extends QIQI Hair Controller results. Smooths, strengthens, and locks in shine. 98% reported healthier-looking hair after weekly use.
Shop now →See the full QIQI range including treatments, kits, and aftercare →
Common questions
Crosilkquat — FAQ
What is crosilkquat?
Crosilkquat is a quaternized silk amino acid conditioning agent made by Croda. It is derived from natural silk protein and carries a positive electrical charge, which allows it to bind directly to the hair shaft. It improves softness, smoothness, texture, and manageability at very low concentrations.
Is crosilkquat safe for hair?
Yes. Crosilkquat is widely used in professional hair care and has an established safety profile. It is a gentle conditioning agent that works at very low concentrations — meaning products need only a small amount to deliver noticeable results. It does not build up excessively or weigh hair down.
What products contain crosilkquat?
Crosilkquat is found in professional-grade aftercare products, including the QIQI Super Soaker Smoothing Masque and other QIQI aftercare formulas. It is one of the key ingredients responsible for the silk-like softness and long-lasting smoothness these products deliver.
Is crosilkquat good for damaged hair?
Particularly good for damaged hair. Because crosilkquat carries a positive charge, it is attracted to the most negatively charged areas of the hair — which are the damaged, porous sections. This means it concentrates its conditioning effect exactly where your hair needs it most.
Is crosilkquat natural?
Crosilkquat is derived from natural silk protein. The silk amino acids are then quaternized — a process that gives them a positive charge so they can bond to hair. It is a nature-derived ingredient that has been modified for optimal performance in hair care formulations.
How does crosilkquat compare to regular silicone?
Unlike silicones, which coat the outside of the hair shaft and can build up over time, crosilkquat bonds at a molecular level to the hair fibre itself. It delivers conditioning benefits without the heavy, coated feeling that silicones can leave. It also targets damaged areas selectively, whereas silicones coat the entire strand uniformly.
Free UK delivery over £80
Silk-level softness. Real ingredients.
Professional aftercare with crosilkquat and precision-selected ingredients. Extend your keratin treatment results. Dispatched within 1–2 working days.