How Mizzen+Main acquired new customers 22% cheaper, at 10% higher order value, with Keeper persona seeds
Mizzen+Main and their agency adMixt used Keeper customer personas as Meta lookalike seeds, and verified the results in their own attribution stack within two weeks.
“We have been so happy with the results. This is a significant unlock for the account, as standard Shopify lookalikes haven’t performed as well in the past.”
About
Mizzen+Main makes performance menswear, dress shirts and tailored clothing built from technical fabrics, sold direct to consumer on Shopify. Paid acquisition is run by adMixt, a performance marketing agency.
Years of disciplined testing, and a ceiling that would not move
Mizzen+Main’s paid program was not broken. It was well run: a dedicated team, constant creative iteration, a full audience testing history, and every dollar measured in a best-in-class attribution platform. Over the years the team had tested behavioral lookalikes built from past purchasers, value-based seeds, and broad prospecting at multiple age bands.
The pattern is one most operators recognize. Broad delivered volume at a high cost per new customer. Behavioral lookalikes did better, but a seed list of past purchasers blends very different buyers into one audience: full-price loyalists and discount-triggered shoppers, gift buyers and repeat customers. The lookalike inherits an average of everyone rather than the shape of the best.
Measurement was never the gap. The team could see exactly what everything cost. What no attribution tool could tell them was who their best customers actually were, and how to manufacture more of them.
Personas as seeds: who customers are, not just what they did
Mizzen+Main connected their store to Keeper, which compiled customer personas from their real buyers: clusters built from purchase behavior and enriched demographics, each persona a distinct kind of customer with its own economics, full-price share, repeat pattern, and lifetime value.
The personas surfaced something the audience lists had been hiding for years: demographically similar customers with opposite buying behavior. Two personas can share an age range, income band, and geography, while one buys almost entirely at full price and the other almost never does. Every past-purchaser seed the account had ever used contained both, which is precisely why those lookalikes plateaued.
The play was simple: seed lookalikes from the personas with the strongest economics instead of from blended lists. adMixt pushed two Keeper personas to Meta and built a lookalike from each, in its own ad set with its own budget, running the account’s existing creative.
Then the market answered. Within days, both persona-seeded ad sets were outperforming everything else in the account. adMixt scaled the first seed aggressively, and performance held. A week later the team shipped the second seed unprompted. Within two weeks, the persona seeds were the largest allocation in the account.
“We test audiences constantly, and these behaved differently from day one. Broad 20% lookalikes seeded from Keeper personas beat everything else in the account on new-customer CAC, and held while we scaled spend 3x.”Anna Granstaff, Senior Director of Paid Media, adMixt
Verified two ways
Two independent measurement systems, with different methodologies, told the same story.
Northbeam, the team’s source of truth, measured on a strict clicks-and-deterministic-view model with a new-customer CAC basis: persona-seeded audiences acquired new customers 22% cheaper than all other targets combined, at 10% higher average order value, on roughly a fifth of account spend. When the team tripled persona-seeded spend in a single week, CAC on those audiences improved rather than fatigued.
Meta’s in-platform reporting, read directionally and separately, showed the same shape: the two persona-seeded ad sets ranked as the cheapest acquisition sources in the account, at roughly 2x the return of the best alternative audience, at identical CPMs. Identical creative running simultaneously inside and outside the seed converted at roughly one third the cost inside it. Same ads. Different audience. Different economics.
“We bet on Keeper to understand not only who our customers are but also how they shop. Persona characteristics don’t always determine shopping patterns, and Keeper unlocks that difference.”Natalie Shaddick, SVP of Marketing, Mizzen+Main
Results
- 22% cheaper new-customer CAC, verified in Northbeam
- 10% higher AOV on persona-acquired customers
- Roughly 8x return on persona-seeded spend during the launch window
- Spend scaled 3x week over week with improving CAC
- Second persona seed launched by the agency unprompted within a week
The order-value result deserves its own line: persona-seeded audiences did not just find cheaper customers, they found customers who spend more from their first order.
“The real surprise was the first-purchase order value, especially at a lower cost per acquisition.”Caroline Spearman, Senior Manager of Growth Marketing, Mizzen+Main
Results were measured by the agency in Northbeam (clicks and deterministic view model, new-customer CAC basis) over a fixed multi-week window with both persona-seeded ad sets live, alongside directional Meta in-platform reporting for the same period.