
Protein Leave-in Treatment
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Protein Leave-in Treatment
Protein Leave-in Treatment
Hair is made up of around 90% protein. Over time, that structure weakens, leading to breakage, frizz and loss of shape. This lightweight leave in treatment feeds your hair with the proteins it needs to stay strong, elastic and healthy. Waves feel more resilient, smoother and easier to manage, with less breakage and fewer split ends over time. 150ml
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- Delivered in 2–3 business days
BENEFITS
BENEFITS
- Strengthens weakened strands to reduce breakage and frizz
- Improves elasticity so waves feel bouncier and more defined
- Best when used occasionally when you feel like your hair needs it
- Formulated with powerhouse ingredients like hydrolysed wheat protein (strengthens hair by penetrating the shaft and improving elasticity, repairing damage and adding body and structure to wavy hair), panthenol (adds moisture and shine, also helps make hair more resilient to breakage), and castor oil (a powerful anti-frizz ingredient with lightweight smoothing properties)
- Silicone, sulphate and paraban free
- Safe for coloured or bleached hair
INGREDIENTS
INGREDIENTS
Aqua (Water), PVP, Polyquaternium-37, Hydrolyzed Wheat Protein, Panthenol, Benzyl Alcohol, Sodium Benzoate, Propylene Glycol Dicaprylate/Dicaprate, PPG-1 Trideceth-6, PEG-60 Hydrogenated Castor Oil, Potassium Sorbate, Glycerin, Linalool, Parfum (Fragrance).
SHIPPING & DELIVERY
SHIPPING & DELIVERY
All orders are processed within 1 to 2 business days (excluding weekends and holidays).
UK Mainland Orders - FREE Over £50
All orders are processed within 1 to 2 business days (excluding weekends and holidays) after receiving your order confirmation email. You will receive another notification when your order has shipped.
Free shipping on all orders over £50 to UK mainland (does not include Northern Ireland).
Orders under this threshold cost £4.
Next Day Delivery - £7
We also offer Next Day Delivery for UK mainland orders at £7. Orders must be placed before 1pm (Monday to Friday) to be eligible for next working day delivery.
Orders placed after 1pm, on weekends or on bank holidays will be dispatched the next working day. Next Day Delivery is available on UK mainland orders only and does not include Northern Ireland.
Europe Orders - FREE over €70
Orders under this threshold will cost €10.
Does not include local taxes.
Delivery time is 5 business days.
Australia Orders - FREE over $155
Orders under this threshold will cost $12.
Delivery time is 7-14 business days.
Canada Orders - FREE over $120
Orders under this threshold will cost $17.
Delivery time is 7 business days.
Tracking
When your order has shipped, you will receive an email notification from us which will include a tracking number you can use to check its status. Please allow 48 hours for the tracking information to become available.
If you haven’t received your order within 10 business days of receiving your shipping confirmation email, please contact us at hello@merwave.co.uk with your name and order number, and we will look into it for you.
Once an order is placed we are unable to make any amendments.
This includes order details, like adding products, and also altering your shipping address. You may be able to amend your address using the courier self service options once your order has been despatched. In this instance, we'd recommend proceeding with your order and returning any items you no longer wish for.

Before + After
Check our these real life results, using the Merwave range.
What’s inside
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HYDROLYSED WHEAT PROTEINHYDROLYSED WHEAT PROTEIN
Strengthens hair by penetrating the shaft to help improve elasticity, repair damage and add body and structure to wavy hair.
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CASTOR OILCASTOR OIL
Powerful anti-frizz ingredient with lightweight smoothing properties.
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PANTHENOLPANTHENOL
Penetrates the hair shaft, helping wavy hair retain bounce and softness, leaving it looking defined and feeling healthy.
How to use The Protein Leave-in Treatment
“Years of bleaching and heat styling left my waves weak, snapping and totally lifeless. Hair needs protein to stay strong and elastic, so I created a treatment that was able to repair damage and bring back bounce waves in an instant!”
Our mission
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Real ResultsReal Results
Zero hair retouch, authentic results from products that are tailor-made specifically to care for wavy hair
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Forever LightweightForever Lightweight
Focussed on thoughtfully-sourced ingredients for formulas that never weigh down waves
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CREATING COMMUNITYCREATING COMMUNITY
It’s not just a routine, it’s a lifestyle. Proudly celebrating connection - making waves with over 160,000 and growing!
You + Merwave
Our Merwave community is our heartbeat; see how they shape & inspire us
I’m so pleased I gave this company and its products a chance nearly 2 years ago.
The products work well and do what they say they will.
They last longer than I expected and I use them quite generously.
The Facebook group and blog is great too as it’s as much about technique as products and there is so much help and support there too.
Keep doing what you do please.
Many thanks.
Having had straight hair my whole life I had cancer treatment 6 years ago and lost all my hair. When it first grew back it was super curly but over time it’s just gone to a frizz. Fed up of straightening and in the heat we’ve had it just looking like a frizzy mess, I decided to give merwave a go. What a transformation! I absolutely love my hair for the first time in about 5 years!!! The curls are amazing, no need to wash every day, simple to style, honestly wish I’d found this years ago ❤️❤️❤️
These products are amazing and make my life so much easier to style my hair. I still can’t believe how good my hair looks
These products have changed my hair habits forever.
I was that person constantly straightening my hair due to what I thought was frizz. Tried all the frizz ease products on the market too and pretty much put up with my non-defined hair.
Now I love the wave, embrace it everyday and will not be straightening ever again. Why would I?
If you’ve not tried before, I fully understand your hesitation. I took some time and convincing. But will definitely not be turning back now.
Enjoy your waves, they are unique and lovely.
I kept seeing Merwave advertised for a while befofe i finally decided to try. I've been using Merwave since May (2024) and having committed to embracing my natural waves and my hair is thankful and all the better for it. It's lightweight and smells clean and fresh. I would recommend Merwave to anyone who is thinking about trying it, go for it, you won't regret it!
I started using Merwave after seeing an Insta ad. Yep, the algorithms know how to get me! Anyway, I'm so glad I did, I went from a frizzy, feral haired beast to a less frizzy, wavy/curly beauty. In a moment of madness, I thought I'd try other companies and ended up with limp, unruly hair. Knowing Merwave works for my hair, I went back to it and my hair has it's bounce and waves back. Needless to say, I won't be straying again!