YouTube Influencer Marketing Case Study: Showerhead Success Story

Three years of stagnation, falling numbers of new customers via Meta and Google, exploding costs per new customer - and then the bold step: 150,000 euros budget for YouTube Influencer Marketing. What sounds like a risky bet turned out to be the most successful growth strategy for the sustainable brand Duschbrocken in years. In this detailed Influencer Marketing case study, I will show you how we at Ad Specialist got the brand back on track for growth within 14 months through strategic YouTube Influencer Marketing - with transparent numbers, honest learnings and a CAC that fell from 60 euros to an average of 25 euros (1).

Watch the complete shower chunk case study video here and experience the entire story with all the details.

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Duschbrocken had developed a considerable market position over the years. The appearance in the Lion's Den in 2019 brought the brand into the world of the general public (1). The product impressed with its innovative shape - a solid shower gel that is completely plastic-free and yet offers lots of foam and intense scents. The components of shower bars are purely natural and the shower bars are biodegradable. A single shower chunk lasts about as long as two conventional plastic bottles of shower gel (1).

But despite this solid basis, growth stagnated. The reality was sobering: new customer growth via the previous push channels Meta and Google declined steadily for three years in a row (1). Communication with the target group via classic ads no longer worked as it used to.

What does this mean specifically for an e-commerce company? The previous marketing channels were exhausted. Performance marketing no longer had the desired effect and customer acquisition costs continued to rise. The trust of customers had to be gained in new ways.

It was precisely in this situation that Christoph, one of the two founders, made a courageous decision: Together with me and my team from Ad Specialist, YouTube Influencer Marketing should be tested as a completely new channel. For a conservative Swabian, providing 150,000 euros for influencer campaigns was an exceptionally courageous step - so much investment had never flowed into an untested channel (1).

The challenges of the first influencer campaigns

The launch in August brought several hurdles for the Influencer Marketing campaign: The seasonally fluctuating product launched when summer was almost over. The company had no experience in influencer marketing – no best practices, no contacts with creators or influencers. With a CAC target of 16 euros, expectations were high and there was no historical data for guidance (1). Every campaign was an experiment, every collaboration with influencers a learning experience.

I made it clear to the two founders from the start: This case would be anything but easy. Many agencies would probably have shelled out the 150,000 euros straight away - this is particularly tempting with commission models. But that's not our style at Ad Specialist (1).

YouTube Influencer Marketing means the strategic collaboration between brands and content creators on YouTube to authentically present products to a relevant target group. In contrast to classic advertising or ads, influencers use their connection to the community, their trust and their influence to credibly communicate brand content.

While many brands reflexively turn to Instagram, I chose YouTube - and there were good reasons for that, which this YouTube Influencer Marketing Case Study impressively proves.

The long-tail effect: When content works for the brand over months

The key difference between YouTube and Instagram lies in the lifespan of the content. On Instagram, a story post disappears after 24 hours. YouTube, on the other hand, works fundamentally differently - and this is exactly where the effect of YouTube Influencer Marketing lies.

Videos on YouTube remain. A good YouTube video can collect views for weeks and months and continuously generate sales and revenue. YouTube videos also benefit from Google's search engine power - they are listed prominently in search results and can therefore reach new viewers months after their publication (2).

For a brand with an average shopping cart of around 30 euros net, this long-tail effect is crucial (1). Every euro invested works multiple times and has a lasting effect. The YouTubers and their videos become permanent partners of the brand.

Budget discipline instead of budget burning in influencer campaigns

This is where our way of working at Ad Specialist differs fundamentally from many other agencies in Influencer Marketing: Although a budget of 150,000 euros was available, we deliberately only spent 50,000 euros in the first six months - i.e. only a third (1).

Why this reluctance to influencer campaigns? Because I first wanted to check how the channel actually works. Many agencies would have invested the 150,000 euros directly in collaborations with influencers. But I relied on strategic testing: first test, collect data, optimize - then scale (1).

The first few months were a roller coaster ride - and that's exactly what I expected. Here are the bare numbers from the second half of 2024 (1):

• August 2024: 60 euros CAC
• September 2024: 64 euros CAC
• October 2024: 31 Euro CAC
• November 2024: over 100 euros CAC
• December 2024: 20 Euro CAC

Overall 2024: 38 Euro CAC with 1,189 new customers acquired (1)

At first glance, these figures from the Influencer Campaign don’t look good. Many brands would have thrown in the towel at this point and written off YouTube Influencer Marketing as a failure.

But my team and I knew: This phase is exactly necessary in order to collect the right learnings. Influencer Marketing is not a performance marketing channel that you just “switch on”. It is a complex process that requires patience, data analysis and continuous optimization of collaboration with influencers.

So the reality at the beginning was exactly as I suspected. The numbers didn't look good at first glance, but we knew that this phase was exactly necessary to collect the right learnings (1).

The turning point in December: success of YouTube influencers

The breakthrough came in December 2024: with 20 euros per new customer, we reached the original target area for the first time. Individual placements with YouTube influencers even showed values ​​between 8 and 20 euros CAC (1). So it was clear: The YouTube influencer marketing strategy works as long as we stick with it consistently and optimize the campaigns.

What distinguishes successful YouTube Influencer Marketing from failed campaigns? The details. My team and I built the foundation cleanly from the start (1).

Creator selection: Relevance of YouTube influencers beats reach

Instead of relying on big names with millions of followers, I focused on creators with relevant communities. The criteria for selecting the influencers were clear: German-speaking reach was mandatory. The YouTube influencers had to have their fans and viewers primarily in German-speaking countries (1).

The content creators had to be active in topic areas that fit the product – sustainability, lifestyle, zero waste, beauty. The connection between influencer and brand had to be authentic. More important than pure follower numbers was the commitment of the community and the credibility of the influencers. The engagement rate played a central role (1).

This strategy is in line with the latest trends in Influencer Marketing: Micro influencers with 10,000 to 100,000 followers often achieve better results than mega-influencers because their audiences are more engaged and trust is higher (3).

Tracking, briefing and offer optimization

We have set up precise tracking and briefings for each influencer campaign from the start. Each placement is planned to not only generate immediate revenue, but also provide valuable data for future campaigns (1).

Even in the first few weeks of the YouTube influencer marketing campaigns, it became clear that classic approaches such as a ten percent discount code were not enough. We tested different offers and found the solution: a starter set with a free travel size. The deal felt like real added value - that's exactly what drove conversions up (1).

Communication strategy: Communicate sustainability as an experience through YouTubers

Another critical factor was the way the products were communicated by the YouTube influencers. I chose a different path in the influencer campaigns: sustainability was positioned as a positive experience. Lots of scent, lots of foam, fun showering - and at the same time plastic-free. The message: You don't have to give up anything, you even gain something (1). This form of storytelling by content creators proved to be highly effective.

So we didn't sell sustainability as a sacrifice, but rather as an experience (1).

With the solid foundation from 2024, we started the scaling phase of the influencer campaigns. From January to June 2025 we consistently implemented the learnings. The results speak for themselves (1):

• January 2025: 40 Euro CAC
• February 2025: 25 Euro CAC
• March 2025: 30 Euro CAC
• April 2025: 41 Euro CAC
• May 2025: 26 euros CAC
• June 2025: 28 euros CAC

Overall H1 2025: 25 Euro CAC with 2,688 new customers acquired (1)

The CAC trend of YouTube influencer marketing campaigns fell significantly and stabilized at a profitable level. The number of new customers doubled from 2024 to 2025 - a clear sign of sustainable growth through Influencer Marketing(1).

What makes the difference? Data-driven decisions

Month after month we analyzed the results of the influencer campaigns in detail. Which age groups in the target group work best? Which formats of YouTube influencers perform? Which offers in cooperation provide the greatest leverage (1)?

These learnings were immediately incorporated into the next briefings for the content creators. At the same time, we relied on rebookings of top performers among YouTube influencers to gain stability while we continuously tested new creators (1).

From then on, the work became very data-driven. Month after month we analyzed the results in detail and immediately incorporated the learnings into the next briefings (1).

A milestone was the implementation of an additional attribution model that also took repeat purchases and long-tail effects of YouTube videos into account. The actual ROI of each influencer campaign was even higher than the initial numbers suggested. The blended CAC in the first half of 2025 fell to around 25 euros (1).

New customer rate: More than three quarters through YouTube influencers

The high rate of new customers was particularly impressive. Through YouTube Influencer Marketing, more than 75 percent of all orders came from people who had never purchased from Duschbrocken before. In some rebookings the proportion was even higher (1).

Today, around 14 months after the start of the first influencer campaign, Influencer Marketing accounts for around 20 percent of all new customers at Showerbrocken. For the first time in years, the brand is growing again - and the trend continues to point upwards (1).

By the way, to date we have only spent 113,000 of the 150,000 euro budget - and have not subsequently billed a cent of the agreed commission for six months. Because we didn't want to blindly burn the budget, but rather use it strategically, piece by piece, to achieve the overarching goal (1).

The “3 R’s” of successful Influencer Marketing – Relevance, Reach and Resonance – also played a central role in this YouTube Influencer Marketing Case Study:

Relevance: The YouTube influencers we selected matched the topic of the Shower Broken brand perfectly. Their content revolved around sustainability, zero waste and conscious consumption (1).

Reach: Through my strategic selection of different creator sizes - from micro influencers to larger YouTubers - we achieved an optimal balance between reach and engagement rate (1).

Resonance: The authentic communication of the influencers ensured that the message reached the target group. The fans and viewers did not feel disturbed by crude advertising, but instead received real product recommendations from trustworthy content creators (1).

Successful YouTube influencer marketing campaigns require operational work from agencies and companies: products must be sent to influencers on time so that content creators can meet their deadlines. Briefings need to be continually adjusted to achieve better results when working with YouTubers. Clear agreements with influencers protect both sides. The tracking must run error-free, otherwise a complete influencer campaign can run with zero euro return (1).

Of course, the whole thing also meant a lot of operational work for us. Influencer Marketing often sounds simple from the outside, but in reality it is a complex project. If just one part doesn't work, an entire campaign can result in zero return and quickly cause frustration (1).

Precise implementation was crucial, especially with shower chunks. The reason: Profit only arises with the second order. The average shopping cart of 30 euros net does not cover all costs for the initial CACs. Only when customers buy again does acquisition through YouTube influencer marketing become truly profitable (1). That's why it was so important to implement every detail consistently.

Let’s summarize the key metrics from this influencer marketing case study (1):

• Total budget: 150,000 euros for YouTube Influencer Marketing
• Actually spent: 113,000 euros in 14 months
• New customers acquired: 3,877 total (1,189 in 2024, 2,688 in H1 2025)
• CAC development: From 38 euros (2024) to 25 euros (H1 2025)
• Best Placements: Between 8 and 20 Euro CAC
• New customer share: Over 75% real new customers
• Share of overall growth: 20% of all new customers through YouTube influencers

These numbers are particularly notable in the context of the world of influencer marketing. The influencer marketing industry has grown to $32.55 billion in 2025 – a growth of 35.63 percent (6). The average CPM in influencer marketing fell by 53 percent to $4.63 in 2024, showing that brands are now getting more than twice as much reach for the same cost (7).

73 percent of brands want to work more closely with micro influencers in 2025 as they provide the best engagement-to-cost ratio (3). YouTube remains the platform with the highest engagement rate – an average of 73 percent, well above Instagram or other social media platforms (8).

Patience in the initial phase: The first few months were tough with CAC of over 100 euros. But it was precisely this phase that was necessary to understand what works when working with influencers (1).

YouTube works differently: It takes time for the videos to have their full effect on the target group. The long-tail effect means: A video can still generate sales and revenue in six months (1).

Strategic budget use: 50,000 euros instead of 150,000 euros in the test phase - this decision paid off. Instead of spending the entire budget quickly, we specifically tested, optimized and then scaled (1).

Attention to detail: Tracking, briefings, product shipping, contract management - if even one element doesn't work, the entire YouTube Influencer Marketing campaign can fail (1).

Data-driven optimization: The continuous analysis of age groups, formats and offers enabled us to improve campaigns with YouTube influencers step by step (1).

The success of Shower Chunks through YouTube Influencer Marketing was no coincidence. It was the result of a clear roadmap, data-driven decisions and a willingness to endure the difficult months (1). Duschbrocken had the courage to take new paths, and that's exactly what paid off. YouTube Influencer Marketing is now an integral part of the marketing mix - the brand is growing for the first time in years, and YouTube Influencer accounts for 20 percent of all new customers (1).

This case study shows: We at Ad Specialist see Influencer Marketing as a strategic growth channel for brands. My expertise lies in strategic channel selection, budget discipline, operational excellence, data-driven optimization and long-term thinking (1). Our service covers the entire spectrum: creator selection, contract negotiations, brief creation, tracking setup, campaign management and performance analysis.

Are you and your brand at the point where performance marketing reaches its limits? Are your CACs continually increasing while new customer numbers stagnate? Then YouTube influencer marketing could be exactly the growth lever you need.

Book your free initial consultation with me, Moritz Lambrecht now, and find out how YouTube Influencer Marketing can also become a growth driver for your brand. Send an email or use the contact form to plan the start of your own successful influencer marketing campaign.

(1) Ad Specialist – Shower Chunks YouTube Influencer Marketing Case Study Video Transcript (2024/2025)

(2) Linkr Network: “ROI from Influencer Marketing on YouTube” – https://linkr-network.com/de/blog-collection/der-roi-von-influencer-marketing-auf-youtube/

(3) Later (2025): “2025 Influencer Marketing Report: 2,500+ Campaigns Analyzed” – https://later.com/resources/report/

(4) Mediakix (2017): “Case Study: How H&M Advertises With Celebrity Influencers” – https://cdn2.hubspot.net/hubfs/505330/Influencer-Marketing-5-Case-Studies-Ebook.pdf

(5) ReachX: “Influencer campaigns on YouTube” – https://reachx.de/artikel/influencer-kampagnen-auf-youtube

(6) Influencer Marketing Hub (2025): “Influencer Marketing Benchmark Report 2025” – https://influencermarketinghub.com/influencer-marketing-benchmark-report/

(7) Page One Formula (2025): “Influencer Marketing Cost & CPM Benchmarks (US 2024-2025)” – https://pageoneformula.com/influencer-marketing-cost-cpm-benchmarks-2024-2025/

(8) Aspire (2025): “10 Influencer Marketing Stats You Need to Know in 2025” – https://www.aspire.io/blog/10-influencer-marketing-stats