In just two months, the wellness brand Guday turned a brand-new weekly newsletter into a channel that generated more than 2× the cost of producing and running it. 

Behind that success is MyNewsletter, the first boutique agency in Brazil dedicated entirely to building newsletters for brands, founded by Fernando Kaloustian. 

And powering the whole effort is beehiiv.

This is the story of how a creator-led brand partnered with a specialized agency to make email a core part of their growth strategy — and why the results show the untapped potential of newsletters for E-commerce and DNVBs.

What makes this case so compelling to me is that it shows several important trends:

In this article, I’ll share how Guday approached their newsletter strategy, how Kaloustian has shaped MyNewsletter into a niche agency business, and how beehiiv sits at the center- powering it all.

Why Trust Me

Taylor Cromwell is a writer and strategist focused on the creator economy and solo entrepreneurship. Through her newsletter Creator Diaries and client work with companies like beehiiv, HubSpot, and Stan, she shares insights, case studies, and interviews that show how creators build sustainable businesses.

When Fernando Kaloustian launched MyNewsletter in early 2024, he had a simple goal: to teach creators and entrepreneurs everything about building and growing a newsletter. 

But soon, the market spoke back. Many readers didn’t want a crash course; they wanted someone to take the work off their plate and build the newsletter for them.

By 2025, MyNewsletter had evolved into a high-demand boutique agency — the first in Brazil dedicated exclusively to producing newsletters for companies.

Today, the agency works primarily with digitally native vertical brands (DNVBs) and E-commerce companies, helping them turn email into a strategic growth channel.

One of those clients is Guday, a fast-growing wellness brand co-founded by fitness influencer Manuela Cit and three of Kaloustian’s former classmates from the Link School of Business. 

Kaloustian’s connection to Guday started years before the agency-client relationship. He studied alongside co-founders Enzo, Gabriel, and João in Brazil’s first course dedicated to entrepreneurship. He had followed the brand’s early journey closely, often discussing the newsletter market with Enzo.

So when Guday’s founders wanted to launch a newsletter but weren’t sure where to begin — what content to create, which platform to use — they naturally reached out to Kaloustian.

That collaboration led to Guday Talks, a weekly newsletter designed to strengthen customer relationships, distribute brand content, and subtly but effectively drive sales.

From the start, Guday approached email with a dual focus:

Branding & Relationship-Building

Conversion & Growth

The team wanted to avoid the hard-sell approach of some DTC companies. Instead, they leaned on education and storytelling to nurture the brand’s community while subtly driving demand.

Kaloustian had experience with nearly every major platform, like Substack, Campaign Monitor, and others. But by 2023, after testing the bizness, the business newsletter he ran at the news, on beehiiv, the choice was obvious.

“Since then, it became clear to me that it was the best option on the market for newsletters. And that was before the platform was even as complete as it is today.” — Fernando Kaloustian

beehiiv offered the intuitive design tools, a comprehensive dashboard, and integrated features (referral programs, recommendations, earning) that allowed MyNewsletter to launch and scale campaigns quickly.

For Guday, two features stood out:

The Guday Talks newsletter launched with a ready-made audience — more than 100,000 emails from Guday’s E-commerce customers who had already opted in to receive communications (heavily influenced by Manuela’s engaged audience).

From there, the content mix followed an 80/20 approach:

Here’s an example of what the newsletter looks like: 

Instead of pushing “Buy now!” messaging, each edition focuses on education, explaining the science behind supplements or sharing practical fitness tips, before introducing a subtle call-to-action for Guday products.

The team chose a weekly cadence to balance consistent touchpoints without overwhelming readers.

The early results exceeded expectations:

By the second month, newsletter-driven sales were more than 2× the combined cost of beehiiv and MyNewsletter’s boutique service.

For Guday — a brand projecting R$80 million (~US$15 million) in revenue in 2025 — the newsletter quickly became a high-ROI growth channel.

For Kaloustian, the biggest revelation was how strong the newsletter could be as a conversion channel, even when sales weren’t the primary goal.

He also credits the success to three factors working in harmony:

The program is just beginning. The team’s next focus includes:

For Kaloustian, Guday’s success is proof that DNVBs and E-commerce companies are sitting on a powerful, underutilized asset: their email list.

And for agencies considering expanding into email? Kaloustian is unequivocal:

If you want to see for yourself how you can use beehiiv to level up your email marketing game, try it for free here. 

MyNewsletter is the first boutique newsletter agency in Brazil, founded by Fernando Kaloustian. With a focus on DNVBs and E-commerce brands, the agency helps companies turn email into a high-impact growth and relationship channel.