The strongest brands rarely start with inspiration alone. More often than not, they begin with frustration. Because frustration, at its core, is just a signal that something isn’t working properly – and solving that is what the best founders are built to do.
For Katie Alex and Kate Elizabeth of Tonic X, that frustration came from the anti-ageing supplement space itself: long-winded routines, bad-tasting powders, underwhelming dosages, misleading labels and poor absorption rates throughout.
As specialist nurses working in aesthetics, they had a unique, first-hand insight into where things were going wrong.
So, in true entrepreneurial fashion, they set out to build the solution themselves. That came in the form of Tonic X – a daily shot combining potent anti-ageing ingredients, encapsulated probiotics and essential vitamins and minerals in one streamlined formula.
We sat down with Katie and Kate to unpack the inspiration behind the brand, how they transitioned from long-term best friends to co-founders, and their plans to reshape the supplement category from the inside out.
Finding the ‘X’ Factor
Katie and Kate didn’t necessarily start out with ambitions of becoming founders in the wellness space. Rather, their path to entrepreneurship began far more organically.
“We’re both specialist nurses (and best friends for over 12 years) with backgrounds in women’s health and aesthetics, so we’ve always been deeply embedded in the world of health, wellness and how people age,” explained Katie.
“That professional lens gave us an intimate understanding of what the body needs to age well – and equally, what the supplement industry was getting badly wrong.
“Over years of working with patients and clients, we trialled hundreds of products ourselves and kept arriving at the same frustrating conclusions. That experience planted the seed for Tonic X.”
With a firm grasp of where other brands were falling short, the duo decided to pour all their initial efforts into what ultimately matters most: the formula.
“The very first step was going back to the science,” Kate added. “Rather than rushing a product to market, we spent a considerable amount of time collaborating with scientists and nutritionists to get the formulation right.
“We weren’t willing to launch something that fell into the same traps we’d been criticising. Once we had a formula we truly believed in – combining key anti-ageing ingredients, vitamins, minerals and probiotics in a single daily liquid shot – we built the brand around it.”
The result of that arduous process was Formulation XX, a “daily dose of feel good” promising benefits across anti-ageing, healthier hair, stronger nails, joint support and cognitive function in one 25ml measure.
Positioned as an all-rounder, it combines 12,500mg of hydrolysed marine collagen, 10mg of astaxanthin, encapsulated probiotics, hyaluronic acid, and key vitamins and minerals in a sodium benzoate-free recipe.
Once the product was in hand, the name seemed almost obvious.
“The ‘X’ does a lot of work for us,” Katie continued. “It represents the extra factor, the advanced formula and the missing piece in a modern anti-ageing routine.
“It’s also a nod to our formulation naming convention: Formulation XX is designed for women, and Formulation XY (coming soon) is our men’s formula.
“The word ‘Tonic’ speaks to something restorative, potent and purposeful. Together, Tonic X felt like exactly what we were building: a powerful, targeted antidote to a broken supplement market.”
As any founder knows all too well, taking that step into the unknown is a daunting process. No matter how strong the formula or how bulletproof the plan, there’s no telling how a product will fare once it’s out in the wild.
Recalling those early stages of validation, Kate said there wasn’t one Eureka moment as such, rather a steady stream of glowing reviews.
“For us, it wasn’t one single moment – it was the accumulation of customer feedback once people started using Formulation XX.
“When customers started telling us their skin felt more radiant, their hair stronger, their energy better – and that they were actually enjoying taking it – that’s when we knew we were onto something real.
“People had finally found a supplement routine they could stick to. That consistency is everything.”
Smoothing Out the Wrinkles in Anti-Ageing
When asked what frustrates them most about the current status quo, Katie and Kate didn’t hesitate in their answer.
“Opacity,” they said. “The supplement world is riddled with proprietary blends, underdosed ingredients and clever marketing that obscures what’s actually inside a product.
“Customers are spending serious money on supplements that simply aren’t delivering – because the doses are too low, the absorption is poor, or the ingredients list is frankly misleading.
“Transparency isn’t a nice-to-have for us, it’s a non-negotiable. We list every ingredient, every dose, every time. The industry should be held to a far higher standard.”
There’s something about the name Formulation XX that feels like an antidote – and for Katie and Kate, that’s exactly the point: a considered response to what they believe the industry has been missing.
The product itself sits at the intersection of several different categories, making it difficult to place in any one box. Yet somehow, it manages to condense what should be a complex routine into a ritual that’s more convenient than ever before.
“Everything in one shot – and we mean that literally,” Katie continued. “Formulation XX delivers collagen, anti-ageing actives, probiotics, vitamins and minerals in a single daily liquid shot, formulated for maximum bioavailability.
“Liquid absorbs faster and more efficiently than pills or powders, and because it tastes great, people actually take it.
“No more cluttered bathroom shelves, no more skipped doses, no more guessing whether your supplement is actually working. We’re not just a collagen brand – we’re a complete anti-ageing multi-supplement, and that distinction matters.”
In Formulation XX, the pair certainly have all the ammunition they need to challenge the current market. However, as they’ve discovered, the real task is getting it onto enough people’s radar without compromising their principles.
“Building something great isn’t enough on its own,” said Kate. “You have to tell the story relentlessly and patiently.
“The product can be exceptional, but if the right people haven’t heard about it yet, it doesn’t matter.
“We’ve learned to be just as rigorous about how we communicate the science and the brand as we are about the formulation itself. Education takes time, but it builds the right kind of loyalty.”
Planning For the Future
With rock-solid foundations in place, Katie and Kate have ambitious plans to build Tonic X into a global powerhouse.
Asked where they want the brand to be in three years’ time, Katie said: “The go-to anti-ageing supplement brand in the UK, stocked in major retailers, trusted by hundreds of thousands of customers, and recognised as the brand that finally made the supplement industry accountable.
“We want both XX and XY to be household names, and we want Tonic X to have expanded internationally. The science is there. The product is there. It’s about scale now.”
Checkpoint one on that roadmap is growing distribution channels. Formulation XX is currently available via Tonic’s website, with subscription options starting from £49.49 per month.
However, in what’s a Gymfluencers exclusive, the duo teased a major change on that front.
“We’ve been tight-lipped about it, but Formulation XX could be due to launch in one of the UK’s biggest beauty retailers very soon.”
For now, the message is very much “watch this space”.
Quick-Fire Questions With Katie Alex and Kate Elizabeth
Describe your perfect customer in five words.
Health-conscious, informed, done settling.
As you plan for the second half of 2026, which single goal on your whiteboard would make you feel the year was a success?
Becoming the name people reach for first. We want Tonic X to be firmly established as the go-to anti-ageing supplement in the UK – growing our customer base, building on the community we’ve already created, and making sure anyone who hasn’t discovered us yet, does. Recognition as the trusted name in this space is the only metric that matters to us.
Let’s talk stockists. Where can people find your products, and where do you want to see them listed over the next 12 months?
Right now, you can find us at tonic-x.co.uk, with a subscription service that delivers directly to your door. We also have a Become a Stockist page for anyone in retail or wellness who wants to carry us. Watch this space for some exciting retail announcements over the coming months.
What’s been your highlight of the journey so far?
Genuinely, it’s the reviews. Reading that someone’s confidence has improved because their skin looks better, or that they’ve finally found a supplement they actually look forward to taking every morning – that never gets old. Building a product that people feel proud to be loyal to is everything we set out to do.
The floor is yours. Tell us anything you think our audience should know.
The supplement industry has been getting away with too much for too long – underdosed products, misleading labels, and a race to the bottom on price at the expense of quality. We built Tonic X because we were frustrated with that as professionals and as consumers.
Every decision we make – from the ingredients we choose to the doses we publish – is about earning your trust. We’re not here to sell you something that sits on the shelf. We’re here to genuinely change how you age. If you haven’t tried Formulation XX yet, we’d back it against anything else on the market.
SEE ALSO: 15% Off Tonic X Discount Code
