We tested Kérastase Discipline Fluidissime across multiple hair types to see if it truly tames humidity, speeds up blowouts, and protects from heat. Here is how it performs, who it suits best, and the trade-offs to know before you buy.
Overview
Kérastase Discipline Fluidissime is a lightweight, leave-in anti-frizz spray designed to smooth the hair surface, shield against humidity, and provide heat protection in one step. It is part of the brand’s Discipline line for unruly, frizz-prone hair and is positioned as a quick mist you can use before blow-drying or light heat styling. The promise is straightforward: softer hair with less puff, faster detangling, and a sleeker finish that lasts up to 72 hours, even when the weather is working against you.
The formula feels like a milky, ultra-fine mist rather than a wet spray, which matters if you hate the heavy or sticky feel some smoothing products leave behind. It coats hair evenly with smoothing polymers and conditioning agents to reduce friction and static, so strands slide more easily during brushing and resist swelling in humid air. There is a signature salon-style fragrance that leans floral and slightly warm. It lingers through the day, and the scent will be noticeable if you are sensitive to fragrance.
On paper, Fluidissime consolidates several steps: a detangler, a humidity shield, and a heat protectant rated up to high temperatures. In practice, it works best as the smoothing backbone of a blowout routine. It will calm surface frizz on air-dried hair too, but the most dramatic difference shows up when you pair it with a brush and dryer or a hot brush. If you want a sleek, polished finish that still feels touchable, this is the use case where the spray shines.
Who it’s for
Fluidissime is a strong match for anyone who routinely battles halo frizz, puffiness, or mid-length flyaways. It is especially helpful if you like a smooth blowout that still has movement, or if you live in a humid climate where hair tends to swell by midday.
Based on testing, here is where it fits by hair type and goals:
- Fine to medium hair that frizzes easily: The lightweight mist smooths without obvious residue when you keep the application light. It helps curb static and cuts the fuzzy halo many fine hair types get after a rough blow-dry.
- Thick or coarse, wavy hair: Expect easier detangling, better brush glide, and reduced puff. You will likely still want a small amount of cream or oil on the very ends for extra control or shine.
- Curly and coily hair: Use it as a heat protectant and frizz shield before a blowout or silk press. It is not a curl-defining styler on its own, so if you are wearing a natural curl pattern, layer your curl cream or gel for hold and definition.
- Color-treated hair: The formula is safe for color and helps offset roughness that makes colored hair frizz more easily.
Skip or sample first if you prefer silicone-free formulas or if you are very sensitive to fragrance. Also know that if your goal is strong hold or glass-like straightness without any other product, Fluidissime will not replace a dedicated smoothing cream or finishing serum.
How it feels and performs
The texture is a sheer, milky mist that lands evenly and spreads well with a comb. It adds immediate slip, so knots release with less tugging. When you blow-dry with tension, you get a smooth cuticle and a soft, satin finish, not a stiff or shellacked one. The hair feels like hair, which is a big win if you dislike crunchy styling products.
Detangling: On wet hair, brushing took noticeably less time and fewer passes. That reduced mechanical stress is a quiet benefit if your hair breaks easily. The spray also adds a subtle weight that helps ends sit together instead of fluffing outward.
Frizz control: In moderate humidity, the smoothing and de-puffing are dependable through a normal workday and into the evening. In very high humidity, Fluidissime tames surface frizz but may need help from a small amount of serum on your ends or a quick once-over with a brush and cool air by late afternoon. The anti-frizz claim of up to 72 hours is realistic only if you are not sweating, sleeping on it, or getting caught in heavy humidity for long stretches. With regular life in mind, expect a good day one and a decent day two touch-up.
Shine and feel: The finish reads as healthy and polished rather than mirror-glass. On fine hair, over-spraying can soften volume at the roots, so keep application to mid-lengths and ends. On thick hair, the product makes the surface look sleeker without collapsing natural body.
Heat protection: Fluidissime is positioned as a heat protectant that can withstand high temperatures, which is ideal for blow-drying and for quick touch-ups with a flat iron or curling iron. If you are styling on dry hair, let the mist flash off and feel dry to the touch before you bring heat close. You will still want to keep tool temperatures reasonable, ideally in the 300 to 375°F range for most hair types, to preserve long-term health.
Fragrance: The scent is elegant and a touch perfumey. It is noticeable during application and lightly noticeable after drying. If you are scent sensitive or prone to scalp irritation, apply with care and keep it away from the scalp.
Build-up and wash routine: Like most smoothing sprays that rely on conditioning agents, it can build up if you layer too many products or skip shampoo for several days. A clarifying wash every week or two keeps hair feeling fresh and light without compromising the smoothing benefits on styling days.
How to use for best results
For the sleekest, longest-lasting result, think of Fluidissime as the foundation of your blowout. Technique and dosage matter just as much as the product.
- Start with clean, towel-dried hair. Squeeze out excess water so the mist is not diluted.
- Shake the bottle. Hold 8 to 10 inches from your hair and mist from mid-lengths to ends. Use 3 to 5 sprays for fine or short hair, 6 to 8 for medium lengths, and up to 10 to 12 for thick or long hair. Avoid the scalp to preserve lift.
- Comb or brush to distribute. This ensures even coverage so every section gets smoothing and heat protection.
- Blow-dry with a nozzle and a brush. Work in 2 to 3 inch sections and keep steady tension. Finish each section with a cool shot to set the cuticle.
- Optional polish: If ends still look fuzzy, smooth a pea-size amount of a lightweight hair oil on the last inch or two. This adds gloss without sacrificing movement.
On air-dry days, mist lightly and twist or clip sections as they dry to encourage a smoother lay-down. Expect gentle frizz control rather than salon-straight results without heat.
For second-day refresh, mist sparingly on dry hair, wait 30 to 60 seconds until it feels dry, then restyle with a dryer brush or a flat iron. A light pass is usually enough to seal the cuticle again.
Layering tips:
- Pair with a small amount of cream or oil on thick or highly porous ends for extra control.
- Avoid stacking too many silicones in one routine. If you use a heavy serum, use fewer sprays of Fluidissime.
- Clarify occasionally if hair starts to feel coated or loses bounce.
Pros and cons
- Pros: Lightweight, even mist that smooths without stiffness. Noticeably easier detangling and faster, cleaner blowouts. Reliable heat protection with a soft, satin finish. Helps hair resist midday puff and halo frizz in humidity.
- Pros: Plays well with a simple routine. You can add oil only on the very ends for high shine without greasiness. Good for color-treated hair that needs extra surface control.
- Pros: Flexible use on wet or dry hair. Effective for both a full blowout and quick morning touch-ups.
- Cons: The fragrance is noticeable and may be too strong for sensitive noses or irritated scalps.
- Cons: Contains smoothing agents that can build up if overused, which means occasional clarifying is smart.
- Cons: Not a one-and-done straightening solution for very coarse or coily textures. For that hair type, layer with a cream or serum for maximum control.
- Cons: Over-application can reduce volume on fine hair, especially near the roots.
Final verdict
Kérastase Discipline Fluidissime is a polished, practical anti-frizz spray that earns its place in a modern blowout routine. The lightweight, milky mist makes hair easier to detangle, speeds up styling, and delivers a smooth, touchable finish that holds up well through a full day. It shines in humidity control for most real-life situations and doubles as a capable heat protectant for both blow-drying and quick iron touch-ups.
It is not the right pick if you want a silicone-free formula, a fragrance-free experience, or firm hold without any other product. For very textured or highly porous hair, plan to layer a small amount of cream or oil on the ends to lock things down. For fine hair, mind your dosage and keep it away from the roots for lasting lift.
If your goal is a polished, frizz-minimized blowout that still moves, Fluidissime is easy to recommend. It works across a range of hair types, it is hard to overdo when you spray from the mid-lengths down, and it keeps the finish soft and salon-pretty rather than stiff. Used well, it is the kind of product you will reach for every time the forecast says humidity.
See also
If you rely on heat styling with your anti-frizz routine, compare Kérastase Fluidissime with our guide to the best heat protectants for everyday blow drying and see which tools pair best in our favorite hair dryers for fine, frizz-prone hair.
– For a complementary smoothing oil from the same brand, read our Kérastase Elixir Ultime hair oil review.
– If your hair needs deeper internal repair beneath the frizz control, check our K18 molecular repair mask review.
– For damaged or over-processed lengths, see whether Redken Acidic Bonding leave-in fits into your routine.
FAQ
Does Kérastase Fluidissime provide true heat protection, and up to what temperature?
Yes. Fluidissime is formulated as a heat protectant suitable for common blow-dry and hot tool temperatures. Use it before blow-drying or light flat iron and curling iron work. Let it dry to the touch before you bring a tool close, and keep temperatures in a healthy range, ideally 300 to 375°F, to minimize long-term damage.
Will Fluidissime weigh down fine hair or make it look greasy?
It is lightweight and designed not to leave a greasy film, but dosage matters. Spray 3 to 5 mists from mid-lengths to ends and avoid the roots. If your hair is very fine, start with fewer sprays, comb through for even coverage, and add one more mist only if needed on the ends.
Is Fluidissime safe for color-treated or keratin-treated hair?
It is color safe and can help smooth the cuticle on processed hair. If you have a recent keratin treatment, it is generally compatible, but always follow your stylist’s aftercare instructions and spot test first if you are cautious about fragrance or sensitive scalps.
Can I use Fluidissime on dry hair, or only on damp hair before a blowout?
You can use it both ways. On damp hair, it improves detangling and sets you up for a smooth blowout. On dry hair, mist lightly, wait 30 to 60 seconds until it feels dry, then restyle with a dryer or iron. A little goes a long way on dry hair, so use fewer sprays.
How long does the anti-frizz effect last, and will it hold up in high humidity?
Expect reliable frizz control through a full day in moderate humidity, with a quick touch-up on day two if needed. In very high humidity, it significantly reduces puff and halo frizz, but you may want to pair it with a small amount of oil or do a brief cool-air pass in the afternoon for best results.
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