yolodex
Case Study · Sports Nutrition · Meta
From bottlenecked on briefing, to 82% of new winners in 30 days
How the fast-growing UK sports nutrition brand fourfive stopped creative briefing holding back its growth on Meta, and found its best ad in a format it would never have briefed.
A big bottleneck in our business was creative briefing… Yolodex now runs a couple of times a week and delivers ready-made briefs. The whole bottleneck is now gone for us as a business.
About
An athlete-founded brand, going direct
fourfive was founded in 2018 by George Kruis, who won 45 caps for England, and Dom Day, who played at a World Cup for Wales. The name comes from the shirt numbers the two locks wore. It makes sports nutrition for people who train: Hydro electrolytes, creatine and functional mushrooms, and describes itself as the UK's first BSCG and Informed Sport tested supplements brand.
Seven years ago, Dom and George were packing every order themselves in a shoebox office with no windows. Today fourfive is stocked nationwide in Boots, Holland & Barrett, Sainsbury's and Ocado, and it's going direct. In the 18 months to spring 2026, revenue grew 150% and subscriptions 400%, and Meta sits at the centre of the plan.
01 — Challenge
Growing direct meant new ads every week, and briefing couldn't keep up
Going direct runs through Meta, and Meta runs on new creative. fourfive aims to put dozens of new ads live every week, because when the team hits that number, performance follows.
But like most fast-growing brands, fourfive runs lean. Damian Gosling, Head of Performance Marketing, ran Meta and Google day to day and wrote the static briefs around it. His Mondays went on the performance report and on digging into why ads had worked, then hunting through competitor ads and reviews for ideas. Video briefs sat with co-founder Dom Day, in between running the business.
So briefing slipped, and everything downstream slipped with it. No briefs meant no new ads, and performance tailed off. When something did win, the team doubled down on it and creative diversity fell away, which is the opposite of what Meta's Andromeda ranking system rewards.
Damian already ran a weekly performance report through Claude, but getting a general-purpose model to brief well meant building and feeding it all the context, and it still couldn't make the calls underneath: which problem, which angle, which format was worth a brief.
And a new product launch was about a month away. fourfive needed a steady flow of new, varied ideas, not another dry spell: the briefs its team already wrote, built from its own data, without anyone having to find the time.
We'd have a great few weeks of creative, then a dry spell. Production was never the problem: we could make the statics. Knowing what to make next was.
02 — Solution
The briefs fourfive already wrote, built from its own data, in minutes
fourfive started with Yolodex, an AI agent for creative briefs, in August 2026. What won Damian over was the first walkthrough: “seeing the power of it and what it could produce so quickly, and the quality of the briefs.” Within a week Yolodex had connected fourfive's Meta ad account, decomposed their winners using purpose built models, and built fourfive's persona matrix based on performance data, voice of customer data, and social listening data. fourfive's approved claims went in too, so the briefs stay inside them. “Within a week we were getting briefs out that were pretty strong,” says Dom.
Now Damian asks Yolodex for a batch, and shares the briefs directly with fourfive's designer. He's in it every day; in Dom's words, he “chats to it like it's his best mate.” One morning he had 15 briefs back in 11 minutes. Most of his creative work is now done in the morning, which frees up his Mondays for strategy across Meta and Google.
The biggest change is what the team is willing to try. Yolodex automatically briefs based on external data, and that has pushed fourfive into formats it would never have tested. One brief from August paired an evening-routine angle that almost no competitor was running with a native Instagram-story static. “We wouldn't even think to brief that,” says Damian. “We would be like, well, that's not really an ad.” Within a week it was the biggest spender in the account. “I just don't get it,” says Dom. “Which is why I'm glad I've got something that's telling me what's working, instead of me trying to figure it out all the time.”
And it doesn't just copy what's winning for other brands. “We don't want to just be copying other ideas,” says Dom. “We want it to be our messaging, as our brand.” Yolodex knows Dom and George played professional rugby, and that ambassador Jack Jarvis is running from Beijing to London, and it tunes what's working in the market into stories only fourfive can tell.
fourfive closed the loop from the first launch: every ad carries “Yolodex” in its name, so results trace back to the brief and each batch builds on what won.
I've used plenty of tools that promise a lot and don't deliver. This one has. We've gone from scrambling to brief to having more winning ideas than we can make, and Yolodex is now the driving force behind our Meta activity.
03 — Results
In its first full month: 64% of Meta spend, 82% of new winners and the #1 ad
The first ad from a Yolodex brief went live on 25 August, eight days after onboarding. In September, fourfive's first full month, Yolodex briefs were behind most of what worked on Meta:
- 64% of Meta spend and 64% of Meta purchases came from ads built from Yolodex briefs
- 82% of new winners came from Yolodex ad briefs
- The #1 ad in the account came from a Yolodex brief, and 7 of the top 10 performers came from Yolodex briefs
- 30% CAC reduction over three months
- 6–7 hours a week back for each of three or four people, now spent making content instead of briefing it
The bottleneck has moved. With briefing solved, statics flow every week, and the question is now how fast fourfive can turn around video. “Having that part fixed has led us to looking at our video,” says Damian, “because we can now output so much.”