Quick answer: the best serum for frizzy hair depends on your hair type. For dry, frizzy or damaged lengths with split ends, choose a smoothing serum that seals the cuticle against humidity, such as Hair Repair Complex. For a glossy finish and flyaways, a shine serum such as Liquid Crystals. For fine hair or waves that oils weigh down, a lightweight fluid such as Oil Non Oil. For curls and coils, a nourishing oil-serum such as Illuminating Hair Oil-Serum. If you blow-dry or straighten, use a heat protection serum such as Replenishing Thermal Care Hair Serum. Use a few drops, on the mid-lengths and ends only.
A good anti-frizz serum is one of the quickest ways to make frizzy hair look smoother and shinier. But a serum that's perfect for thick, dry hair can leave fine hair limp, and one made for curls can be too rich for straight hair. Here's how frizz works, what a serum actually does, and how to pick the right one.
What causes frizzy hair?
Frizz happens when the outer layer of the hair, the cuticle, is raised or roughened instead of lying flat. Hair that's dry or damaged soaks up moisture from the air, swells unevenly, and the strands stop lying neatly together. That's why frizz is usually worse on damp, humid or rainy days.
- Humidity. Moisture in the air is the most common trigger, especially for hair that's naturally dry or curly.
- Dryness and high porosity. Hair that loses moisture easily also absorbs it easily, so it reacts more to the weather. Our guide to hair porosity explains how to test yours.
- Damage. Colour, bleach, heat styling and split ends leave the cuticle rough and raised. Read more in how to treat dry, damaged hair.
- Friction. Rough towel-drying, cotton pillowcases and over-brushing all ruffle the cuticle.
- Your natural texture. Wavy, curly and coily hair is more prone to frizz because the cuticle doesn't lie as flat along the bends of each strand.
- Winter. Cold air outside and central heating inside dry hair out, so frizz and static often get worse. See our winter hair care guide.
What does an anti-frizz serum do?
A hair serum is a leave-in product for the lengths and ends. Most anti-frizz serums work by coating the hair in a fine, flexible film. That film smooths the cuticle so the hair reflects more light, helps strands lie together, and slows down how quickly hair takes on moisture from the air. The result is smoother, shinier, more manageable hair that holds its shape for longer.
A serum is a finishing and protecting product, not a deep treatment. It can seal split ends so they look neater, but it can't reverse them: only a trim removes split ends. For dry or damaged hair, a serum works best alongside a moisturising shampoo, conditioner and mask.
Silicone serums, oil serums and lightweight fluids
Anti-frizz serums broadly fall into three types, and knowing which you're buying helps you choose.
- Silicone serums give the strongest smoothing, slip and humidity resistance, and the most mirror-like shine. They're ideal for thick, dry, frizzy or damaged hair. Our Hair Repair Complex and Liquid Crystals contain silicones. We use them only in products for the lengths, because there is currently no naturally derived alternative with the same smoothing performance.
- Oil serums use plant oils to soften, add shine and tame flyaways. They're lovely on curls, coils and dry ends. Illuminating Hair Oil-Serum is made with rice bran, sweet almond and argan oils, with no silicones in its ingredient list.
- Lightweight fluids give an oil-like smoothness without the weight. They're best for fine hair and anyone who finds oils and silicone serums too heavy, like Oil Non Oil.
How to choose the best serum for your frizzy hair
| Your hair | Best type of serum | Our pick |
|---|---|---|
| Dry, frizzy or damaged, with split ends | Smoothing silicone serum | Hair Repair Complex |
| Frizz and flyaways, and you want high shine | Shine serum | Liquid Crystals |
| Fine hair or loose waves that oils weigh down | Lightweight anti-frizz fluid | Oil Non Oil |
| Wavy, curly or coily | Nourishing oil-serum | Illuminating Hair Oil-Serum |
| You blow-dry, straighten or curl most days | Heat protection serum | Replenishing Thermal Care Hair Serum |
The best Insight serums for frizzy hair
1. Hair Repair Complex: best for dry, frizzy, damaged hair and split ends
Hair Repair Complex is a smoothing hair repair serum for the lengths and ends. It has a powerful anti-frizz effect that protects the cuticle from humidity, helps seal split ends, and makes hair easier to comb and manage. It's made with mosqueta rose oil, sunflower oil and organic althaea, calendula and mallow extracts. Use a few drops on damp or dry hair. If your frizz comes with dryness, breakage or split ends, start here.
2. Liquid Crystals: best for shine and flyaways
Liquid Crystals is Insight's award-winning shine serum, voted Best Serum in the Hair Magazine Hot 100 (Pro) 2022. It's a lightweight fluid that smooths frizz and flyaways and adds brilliant shine without weighing hair down, with organic sesame and linseed oils. It's the perfect finishing touch after styling, and a favourite in salons.
3. Oil Non Oil: best for fine hair and waves
Oil Non Oil gives all the smoothness of an oil without the weight. It controls frizz for hours and leaves hair shiny and hydrated, with no greasy residue, thanks to organic aloe, ginkgo biloba and panthenol. It's ideal if serums and oils usually leave your hair flat. Shake, then apply to damp or dry hair.
Pro tip: Lorraine Matic, Head of Insight UK Education, mixes Oil Non Oil with Replenishing Thermal Care Hair Serum before a blow-dry for protection and shine.
4. Illuminating Hair Oil-Serum: best for curls and coils
Illuminating Hair Oil-Serum adds shine, softness and elasticity, and is especially good on waves, curls and coils. A few drops smooth the lengths and tame flyaways without greasiness. It blends rice bran, sweet almond and argan oils with organic coconut, chia and sacha inchi. For more on curls, read our guide to the best hair oil for curly hair.
5. Replenishing Thermal Care Hair Serum: best if you use heat
Replenishing Thermal Care Hair Serum is a lightweight leave-in serum that protects hair from blow-dryers, straighteners and curling irons up to 230°C, and leaves it smoother, frizz-resistant and very shiny. Apply it to damp hair before you blow-dry. If heat styling is part of your routine, this is the one to use first. Our heat protectant guide explains the right straightener temperature.
Browse every option in our hair oils and serums or the full anti-frizz styling edit.
How to use an anti-frizz serum
- Start small. Two or three drops is enough for most hair. Add more for very thick or long hair. You can always add more, but too much looks greasy.
- Warm it between your palms. Rub your hands together so the serum spreads evenly instead of landing in one spot.
- Apply to the mid-lengths and ends. Keep serum away from the roots and scalp, where it can make hair look flat or oily.
- Use it on damp hair to prevent frizz. Applied after towel-drying, serum smooths the cuticle before you style. Blot hair with a microfibre towel or cotton T-shirt rather than rubbing.
- Use it on dry hair to finish. A drop smoothed over the surface tames flyaways and adds shine once you've styled.
- Protect before heat. If you blow-dry or straighten, apply a heat protection serum or spray to damp hair first.
Anti-frizz serum mistakes to avoid
- Using too much. The most common reason hair looks greasy or flat.
- Applying it to the roots. Serum belongs on the lengths.
- Skipping conditioner. A serum smooths the surface, but dry hair still needs moisture underneath.
- Rubbing hair with a towel. This roughs up the cuticle and undoes your serum's work.
- Brushing dry curls. Brushing curly hair when dry breaks up curl clumps and creates frizz. Detangle curls when wet, with conditioner in.
Build an anti-frizz routine
A serum works best on hair that's already well moisturised. Our Hydrating range is made for frizzy hair: wash with Hydrating Shampoo, condition with Hydrating Hair Conditioner, and use Hydrating Hair Mask once a week. Shop the full Anti-Frizz range. Then finish with the serum that suits your hair type. If your hair is curly, add a curl cream too: our guide on how to use curl cream shows you how.
Frequently asked questions
Is serum good for frizzy hair?
Yes. An anti-frizz serum smooths the cuticle, helps strands lie together and slows down how much moisture hair absorbs from the air, so hair looks smoother and shinier and frizz is reduced. Choose one that suits your hair type so it doesn't weigh hair down.
Should I apply serum to wet or dry hair?
Both work. Apply to damp hair after towel-drying to prevent frizz before styling, and use a drop on dry hair to tame flyaways and add shine afterwards.
What's the best serum for dry, frizzy hair?
For dry, frizzy hair, especially with split ends, a smoothing serum that protects against humidity works best. Hair Repair Complex is made for this. Pair it with a moisturising shampoo and conditioner such as our Hydrating range.
Are silicones in hair serums bad?
Not for most people. Silicones give the best smoothing and humidity resistance, which is why they're used in many anti-frizz serums. If you follow the curly girl method or simply prefer to avoid them, choose an oil-serum with no silicones in the ingredient list, such as Illuminating Hair Oil-Serum, or a lightweight fluid such as Oil Non Oil.
Can I use serum every day?
Yes, in small amounts on the lengths and ends. If hair starts to feel coated or heavy, use less or wash with a clarifying shampoo now and then.
Does serum repair damaged hair?
A serum can make damaged hair look and feel smoother and seal split ends so they look neater, but it can't reverse damage. Regular trims and nourishing care do the rest. Read our guide to split ends.
What's the difference between a hair serum and a hair oil?
Serums are usually lighter and designed mainly to smooth, protect and add shine to the surface of the hair. Hair oils focus more on softening and nourishing, and some can be used as pre-wash treatments. Our guide is hair oil good for your hair? explains more.
Which serum is best for curly hair frizz?
Curls usually love richer, nourishing oils. Illuminating Hair Oil-Serum is made for waves, curls and coils. Apply it to damp hair, scrunch, and avoid brushing once dry.
About the author
Charlotte Read has spent six years in the hair industry with Insight Professional and holds a First Class BSc in Business Management and Marketing. She writes with reference to real salons across social media and the wider Insight community, and draws on the Insight office team, who between them bring over 100 years of combined experience on salon floors.
Where technical expertise is needed, Charlotte consults Lorraine Matic, Head of Insight UK Education, who brings over 38 years of global experience in colour, technique and hair science.