Topicals: Proving the cross-channel value of GMV Max and driving Amazon revenue up 3.7X

The Challenge

Topicals had a strong conviction that GMV Max was driving value far beyond TikTok Shop’s impact. The team could see the signals - stronger Amazon sales, rising DTC traffic - that correlated with GMV Max activity, but they could only see GMV Max's impact on TikTok Shop sales. The Amazon and DTC revenue that GMV Max was also influencing remained unmeasured, which meant the team didn't have the business case internally to scale the channel to its full potential.

Without a way to quantify the cross-platform impact, there was no defensible number to take into a budget conversation. As a result, the Topicals team had to cut GMV Max spend in January 2026 - not because they believed the channel wasn't working, but because they couldn't prove it was.

Traditional measurement alternatives couldn't solve this either, for these reasons:

• MTA tools that rely on pixels can't place a third-party pixel on Amazon or TikTok Shop, so the cross-platform journey is invisible.
• Traditional MMMs offer a broader view but typically deliver quarterly - far too slow for the pace of GMV Max optimization.
• Incrementality experiments can only measure the lift across two channels at a time, so they don't offer a full cross-channel view.

The Solution

Fospha's GMV Max Halo measurement solved a problem that traditional tools structurally cannot: a daily Total Commerce ROAS that tracked the full impact of GMV Max impressions across TikTok Shop, Amazon, and DTC in a single view - combining the cross-channel scope of an MMM with the daily cadence needed to act on it.

With Fospha's measurement providing the confidence to act, Topicals moved decisively:

• 460% increase in GMV Max investment in February, making it the primary driver of their TikTok strategy.
• 3.7X uplift in Amazon revenue in the same period, reinforcing GMV Max's role as a cross-channel demand driver.‍
• GMV Max repositioned from at-risk line item to highest-conviction channel in the media mix.

"We always felt GMV Max was doing more than TikTok's reporting showed - we could see the ripple effects on Amazon and DTC, but we had no way to put a number on it. When Fospha showed us the full picture, a 3X halo on our GMV Max spend, it changed everything. We went from cutting budget in January to making GMV Max the centrepiece of our TikTok strategy in February. The data gave us the confidence to move fast - and the Amazon results proved we were right." – Helena Youhana, Head of Growth, Topicals

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The Measurement Difference

TikTok Ads Manager is built to measure GMV Max's impact on TikTok Shop. Fospha helps by extending that view across the full customer journey, capturing the Amazon and DTC revenue that GMV Max also drives. Together, they give brands a complete picture of cross-channel profitability.

For Topicals, that extended view revealed a 3X ROAS multiplier that was invisible to any single ad platform.

Fospha's data consistently shows that brands using GMV Max Halo measurement average a 1.8X Total Commerce ROAS uplift vs. in-platform reporting, with 100% of customers seeing higher true ROAS than their platform-reported figures (based on 5 beta clients measured Nov–Dec 2025).

The Bottom Line

TikTok Ads Manager shows what GMV Max delivers on TikTok Shop. Fospha shows the full story, including the Amazon and DTC revenue that completes the picture. Together, they give brands the measurement confidence to scale.

Topicals used Fospha to quantify what they'd always believed: that GMV Max was their most powerful cross-channel growth lever. That insight turned a January budget cut into a 460% scale - and a 3.7X uplift in Amazon revenue.

When brands can see GMV Max's real ROI across their full business, the case for scaling it becomes automatic.

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Footnotes

Impact type: Blended business impact across TikTok Shop, Amazon, and DTC
Time range & period comparisons: February 2026 vs. January 2026
Markets analyzed: United States (US).