Built on Trust. Sustained by Results.
A long-term product testing partnership with a global consumer brand
The Relationship
Some clients send a brief. Our longest-standing product testing client sends the next one before the first has even landed.
What started as a single study four years ago has grown into one of Zest’s most significant ongoing partnerships. Fifty-two studies in year one. Eighty in year two. One hundred and thirty-three in year three. One hundred and forty-nine last year, with sixty more already forward-booked for the year ahead. Not because a contract demands it, but because the work is done properly every time and the client has stopped looking elsewhere.
Over those four years Zest has become embedded in one of the world’s leading consumer brands’ research operations, supporting product development across their full portfolio, from floorcare and cookware to haircare and skincare, through a programme that runs continuously throughout the year.
Methodologies:
In-Home User Tests, Focus Groups, In-Home Interviews, On-Location Salon Days
Scale:
149 studies in FY2025-26. 60 forward-booked in FY2026-27 to date
Services:
Recruitment, product verification, participant support, logistics, hosting, collection and controlled destruction
What We Run
Across this partnership Zest runs the full spectrum of product research methodologies. In-home user trials place products with verified, quality-checked participants for extended periods, tracking real usage, gathering diary entries and survey responses, and flagging issues in real time. Focus groups bring participants together for structured product feedback. In-home interviews send our team directly to participants alongside the product, with travel routes and transportation organised by Zest. And for on-location salon days, we recruit and quality-check participants, manage the process, and provide a dedicated Zest host to ensure every participant arrives prepared and the session runs without friction.
Across every methodology, the infrastructure is the same: meticulous recruitment, direct participant management, and a dedicated Zest team that owns every detail from first contact to final sign-off.
A Study That Shows What This Looks Like
When the client needed to test a prototype LED face mask before launch, they needed 300 everyday users across the UK, tested, tracked, and reported on with strict confidentiality. Half the sample were required to be verified existing owners of LED face masks, so Zest built a multi-stage verification process, collecting proof of ownership and securing client sign-off on every participant before onboarding. No shortcuts. No assumptions. Three hundred verified, quality-checked testers.
Over two months, participants used the device as part of their everyday routines. Throughout the trial Zest managed participant communication directly, provided troubleshooting support, flagged emerging issues to the client in real time, and maintained a consistently high survey response rate across the full sample. On completion, all 300 prototype units were collected and sent for controlled destruction.
Working with Zest to test our first LED mask with consumers was a fantastic experience. The project was complex, skincare was a completely new space for the business, and the volume of studies required to ensure a highly consumer-satisfying product was very large. Despite the clear challenges, Zest successfully accomplished all our requests, finding great quality testers who allowed for excellent diversification. They were extremely flexible any time the research required a pivot, which frequently happened given the new space we were operating in. I am really grateful to the Zest team for all they've done and the excellent support they provide, no matter how challenging a project we propose.
The Same Standard. Every Study.
The LED mask trial is one example from hundreds. What makes this relationship work isn’t that Zest pulled out something special for a high-profile project. It’s that the same standard applies to every brief in the programme, whether it’s a small in-home interview study or a 300-unit prototype trial.
What This Says About Zest
Relationships like this are built slowly and lost quickly. The only way to sustain a programme at this scale, across this many methodologies, over this many years, is to hold the same standard on every study. Not just the ones that feel important.
52 studies in year one. 149 in year four. A fifth year already taking shape.
We needed to run an in-home usage test for a new microwave product, which required careful coordination of unit shipment to consumer testers across multiple locations. A logistically complex operation that needed to run smoothly to protect both our research timelines and our product. Zest are brilliant partners at working with our fast-paced expectations and always deliver in a timely manner. They handled everything from shipping units out to testers, managing incoming queries, collecting units back in, and even setting aside selected units to return to us, all with great attention to detail and clear communication throughout. They felt like a genuine extension of our team, and we wouldn't hesitate to work with them again.