I Tried Hair Filler for Faster, Smoother Styling—and It Exceeded Every Expectation

My relationship with my hair has come on leaps and bounds over the last few years. After spending the entirety of my teens and much of my twenties frying it with hair straighteners, my thirties has been a decade of hair acceptance. Sure, my hair’s natural texture (a thick mass of waves, curls and straight sections) means that it will always be prone to frizz and dryness, but with a new love of air dry creams, I’ve come to quite like my hair's natural texture.

However, I’ve reached this point where I've largely lost faith in hair treatments, due to years being disappointed by empty promises that they will smooth, de-puff and rid hair of frizz, only to find that my hair is either left exactly as it was before, or else completely devoid of my natural texture.

Mica Ricketts with natural hair, before SmoothFiller treatment.

So when an email landed in my inbox about Wella SmoothFiller, a demi-permanent salon treatment that promises smoother, shiner, easier to manage hair without dramatically changing your hair texture, it caught my attention. I’ve always been wary of keratin treatments because many of them totally smooth out curls and waves to be pin-straight. I still want my hair to have movement and bounce, and I’d love my natural waves to shine—just without the flyaways diffusing their shape. Here’s what happened…

What Is SmoothFiller?

When I arrived at the salon, my lovely hairstylist talked through the steps of the process really clearly to me and explained that my appointment should take around two hours. Firstly, my hair was washed (with shampoo only, no conditioner) to make sure it was clean of product and then it was rough dried until it was about 80% dry.

Next, the SmoothFiller itself was applied. My hair was sectioned and the stylist painted the treatment evenly onto each section of the hair from the tips up to the roots.

What actually is SmoothFiller I hear you ask? It’s an innovative new smoothing treatment from Wella that uses a minimalist formulation of just eight ingredients, including an organic acid that works to restructure the hair from within. Frizz tends to be caused by gaps and tears in the actual shaft of the hair, and SmoothFiller effectively comes in to refill those gaps, builds more bonds inside the hair and smooths the cuticle for more shine, less frizz and added protection from humidity. The application was really easy and I was impressed that there were no weird smells or fumes at all when it was being applied. After my hair was coated, I was left for 20 minutes to enjoy a cup of coffee and read my book while the treatment got to work.

After the time was up, the SmoothFiller was thoroughly rinsed out and it was time to activate it. The stylist blow-dried my hair until it was totally dry, and even at this stage I was impressed at just how smooth my hair looked. Normally while my hair is being blow-dried it has already started to frizz and puff up, but even though I could see my natural waves emerging there were none of the usual flyaways.

Once it was dry, she then sectioned my hair and went over it all with straighteners. Because my hair is fairly coarse in texture she did a few passes on each section to really lock in the smoothing effect.

And that was that—I walked out the salon with smooth, sleek, shiny hair that felt really healthy too. It’s almost like my hair had some extra weight to it, and it felt really full and thick. Unlike other smoothing treatments, there’s no need to worry about getting your hair wet or having to worry about the damp British weather when you step outside either. You can wash your hair whenever you like post-treatment and then get back to your usual styling routine.

Results of the Treatment

As mentioned, I was immediately impressed at how smooth and shiny my hair was post-SmoothFiller, but I knew that the real test would be how it fared after I had washed and styled it myself. After all, I am no professional hair stylist. I did love that I could wash my hair pretty much immediately and with my usual shampoo too, especially as I never feel totally myself when wearing my hair poker-straight. And I was keen to see how my natural texture would fare post-treatment.

To put it through its paces I washed and conditioned it as normal and then left it to air dry without any product in. This would usually mean that my hair would dry in a rather chaotic wavy jumble with an immense amount of frizz, but while my waves were undoubtedly there they looked much more uniform in shape and way more glossy. I asked my husband if he thought my hair looked any different and he said “less puffy”, which I’ll take as a compliment from one of the world’s most unobservant men.

The next time I washed my hair, I decided to style it using a blow-dry brush—a tool that I love but rarely reach for because I always struggle to get the kind of polished results that I’m after. This time though, my hair transformed into a smooth, bouncy, blow-dry with ease. And, crucially, remained that way even after a couple of school runs in autumn downpours.

Is SmoothFiller Worth It?

Mica Ricketts with air-dried hair after SmoothFiller treatment.

For me, SmoothFiller feels exactly like the kind of hair treatment I’ve been waiting for—smoother, more manageable hair without waving goodbye to all of my natural texture. I love that you get immediate results, there’s no tricky upkeep, and you don’t have to heat style your hair religiously to benefit from it either. We all have super busy lives and this treatment undoubtedly makes styling so much simpler and elongates that style by reducing the effects of humidity on the hair.

However, there are trade-offs to consider. SmoothFiller has a substantial cost: starting from £250, depending on your salon, hair length and thickness, with my stylist estimating that my hair would cost around £290. For a treatment that only lasts up to 3 months it’s quite a financial commitment as you’d need around 4 treatments a year to maintain that level of polish. For me, that does feel like quite an investment despite how much I love the results. However, the fact that it fades gradually, rather than growing out from the root like some other straightening treatments, does mean that you don’t have any harsh and obvious regrowth as it fades which I like.

Overall, if you have frizz-prone hair like mine or hair that’s prone to consistent flyaways or succumbs to the humidity, and you want to cut down your daily styling time then SmoothFiller is an excellent option—if budget allows.