Otrium’s market expansion, paid digital optimization & 80% higher ROAS using Trustpilot

Otrium is an online fashion outlet on a high-stakes mission: to ensure that "all clothing produced is worn". By connecting excess stock from leading brands with a community of over 4 million fashion lovers, they provide a sustainable solution to the industry's waste problem.

However, in a saturated digital landscape where consumers see up to 10,000 ads daily, standing out requires more than just a great mission. It requires transparency & community.

Social proof in the fashion industry to convert new consumers

In the competitive fashion sector, 72% of Dutch consumers state that ratings and reviews are essential to their purchase decisions. For Otrium, which offers premium archive collections at deep discounts, the primary challenge wasn't the product; it was to improve performance. To convert a new user, they first had to prove their legitimacy in a world of skeptical digital shoppers, especially when expanding to in focus markets.

Breaking through the noise in the AI era

Otrium's original paid social strategy was 100% conversion-focused. However, as AI-generated content and increased competition made traditional brand ads less effective, they realized they wanted a "foundation of trust" to stand out in a different way and lower acquisition costs. They hypothesized that adding social proof would not just drive clicks, but drive high-value action. 

Otrium pivoted from a 100% conversion-focused model to a strategic full-funnel approach, allocating 20% of their budget to awareness

80% Higher ROAS in European Expansion

Recognizing that different markets require distinct strategies,they integrated verified social proof (Trustpilot stars and reviews) into their social ad creative to serve two specific goals across Europe: market penetration with improved efficiency and revenue impact.

As one of the largest countries in Europe, Germany represents a strategic focus for Otrium, and it was a strategic move to test Trustpilot in the market to successfully accelerate in a highly competitive market by building trust with first-time shoppers.

The marketing team executed a three-week A/B test on Meta within the consideration layer, comparing standard brand ads against creatives featuring the Trustpilot logo and star rating. 

The results: accelerated customer acquisition with social proof and credibility. 

The ads that included Trustpilot-content delivered undeniable efficiency, lowering the cost and risk of expanding in the country:

• 80% increase in Return on ad spent (ROAS), proving that social proof is a powerful revenue driver for new user acquisition.

• 25% lower Cost-per-view (CPV), making their consideration campaigns significantly more efficient.

• An 8% lift in Average Order Value (AOV), indicating that new shoppers who trust the platform are willing to spend more.

"Featuring Trustpilot elements builds social credibility, which positively impacts new user acquisition, particularly for those considering their first purchase with us."

— Rocío Villares, Senior Paid Social Media Manager

Optimizing in the Netherlands: 70% higher ROAS

In the Netherlands, the goal was slightly different. As Otrium is originally a Dutch company, here the team focuses on general impact on performance on optimizing brand perception. Otrium’s hypothesis was that featuring Trustpilot reviews in our social ads would positively impact their performance.

 The team applied a social ads test integrating Trustpilot elements into their Awareness layer to validate if this would lower their Cost Per Mille (CPM). 

To test effectiveness, they performed a 1-month observational test in the Netherlands and compared performance of new ads against the benchmark of existing ad group.

The impact across the campaign was undeniable, establishing a new efficiency standard for a high-growth market:

• 70% higher ROAS than standard benchmarks.

• A 5-7% lower Cost Per Mille (CPM) than their standard campaign average, 

• 11% lower Cost Per Acquisition (CPA) compared to campaign averages.

"Trustpilot review ads boost conversion efficiency while delivering awareness at lower cost. Overall, Trustpilot review ads have proven to be a strong fit within Otrium's content mix."

— Rocío Villares, Senior Paid Social Media Manager

The paid potential of Reddit & social proof

Similar to seeing that Trustpilot is a much cited brand by ChatGPT & Google AI Overviews, the team recognized Reddit as an untapped paid digital channel. Otrium moved quickly to activate paid advertising there. This approach allowed them to directly insert their Trust-backed ads (which had already proven successful on Meta) into the very communities where skepticism was highest, turning user-generated content into high-conversion touchpoints and providing verified social proof precisely where their audience was researching and forming opinions.