Email Marketing + AI Humanization: 34% Higher Open Rates
Email marketing is probably the most data-driven channel in the modern marketer’s arsenal. We know exactly how many people opened it, clicked it, converted on it. We A/B test subject lines obsessively. We segment audiences down to the individual level. We optimize send times to the hour. But despite all that optimization, many email programs still struggle with a basic problem: their emails don’t feel personal, even when the data says they should.
Michael Torres runs email marketing for Relay Marketing, a B2B marketing automation platform. He oversees campaigns to about 45,000 opted-in subscribers. His team sends roughly 15-20 campaigns per month, and they’re aggressive about testing. But they kept hitting a ceiling on their open rates that seemed hard to break through.
The Open Rate Problem
Relay’s email program was performing well by industry standards. Their average open rate was around 38-40%, which is solid for B2B email. But Michael knew they could do better. He had subscriber segments with higher engagement, fresher lists, clearer value propositions. Those segments should have been opening his emails at 50%+ rates. Instead, they were opening at similar rates to the rest of the list.
When Michael dug into the problem, it came down to voice. Relay’s emails read like they were written by a marketing team optimizing for clicks. Which, to be fair, they were. But that optimization was creating a wall between the email and the reader. The subject lines were clever. The copy was clean. But it all felt slightly polished, slightly rehearsed, slightly not-from-a-human.
Michael experimented with different approaches. He tried longer-form emails. He tried personal anecdotes. He tried humor. But consistency was the problem. A single email writer might nail the human voice, but the next email in the series would sound different. That inconsistency was confusing the audience.
Finding a Voice That Scales
Michael’s team consists of two full-time email writers, which is typical for a company Relay’s size. Those two people were responsible for all campaign copywriting, testing, and optimization. They were good at their jobs, but they couldn’t write every email while also managing the strategic side of the program.
Michael ran an experiment. He gave his team a set of brand voice guidelines and had them write 5-10 template emails that exemplified the voice he wanted to establish: conversational, direct, honest about what Relay does and doesn’t do, helpful without being salesy. Those became his reference library.
From that point on, the process worked like this: Michael or his team would write a draft email based on the strategic goals and the message they wanted to convey. That draft would get run through an AI humanization tool tuned to match the brand voice established by those reference emails. The output would be reviewed by one of his writers, tweaked if necessary, and sent.
The effect on consistency was immediate. Every email now sounded like it came from the same person, thoughtful, direct, genuinely trying to help. Even though two people were writing the drafts and a machine was doing the refinement, the voice remained consistent.
The Metrics That Changed
Within two weeks, Michael saw his open rates jump from 38-40% to 42-43%. That might not sound dramatic, but in email marketing, a 3-5% increase in open rate is significant. It compounds across your subscriber base and your sending volume.
But the real gains came over the next two months as he ran more campaigns through the system and refined the process. His overall email open rate eventually stabilized at around 52%, which represents a 34% improvement over his previous baseline.
Click rates improved too, but not by as much, around 18% improvement. That makes sense because humanized copy opens more emails, but it doesn’t necessarily make people click more if the call-to-action isn’t aligned with their interests. Michael realized this meant he should focus his optimization energy on segmentation and audience targeting, not just the copy itself.
Unsubscribe rates actually decreased slightly, which was surprising. Michael’s theory: when emails feel genuinely helpful rather than salesy, people stay subscribed longer because the content actually provides value. That’s a second-order benefit that doesn’t show up in open-rate metrics but matters for long-term list health.
Conversion rates from email improved by about 22%. Again, this isn’t all about the humanization, it’s about consistency, better segmentation, and having more time to optimize the strategy because the writing process became faster. But humanization played a role.
Why This Works for Email Marketing Specifically
Email is the channel where voice matters most. Unlike a landing page where the visitor is already committed to engaging, an email needs to earn the reader’s attention in the subject line and then earn their continued attention in the preview and body. An email that sounds like a marketing team loses that battle before it starts.
But hiring five talented email copywriters to maintain consistent voice isn’t scalable for most companies. Michael’s team is doing that work through humanization: one good writer (or a small team) establishes the voice, then that voice scales across dozens of campaigns. That’s the trick that makes everything else possible.
There’s also an efficiency element. Michael’s writers now spend less time wrestling with tone and more time thinking about strategic things: what should we message, who should we message it to, what should they do next. That higher-level strategic work has more impact on business results than marginal improvements to individual sentences.
How They Built and Refined the System
Michael didn’t just plug his email drafts into a humanization tool and hope for the best. He was intentional about training the system to match Relay’s voice. He provided reference emails that exemplified the voice he wanted. He wrote brand voice guidelines that were specific and behavioral rather than abstract (not “be conversational” but “address the reader as someone doing hard work, acknowledge their constraints, offer specific help”).
He also established a review process. Every email goes through one of his writers before sending, which means they catch things the tool might miss, industry-specific terminology that needs preservation, context that needs clarification, strategic messages that need emphasis. That human review step is crucial. It’s not a rubber stamp. It’s the last line of quality control.
Another detail that helped: Michael treated each campaign like a small experiment. After sending an email through the system, he’d analyze the performance, share learnings with his team, and adjust the guidelines or templates if something wasn’t working. That iterative approach meant the system got better over time, which is how you turn a good idea into a sustainable system.
One Unexpected Challenge
The one complication Michael ran into was explaining the system to stakeholders. Some executives were concerned that “AI-written” emails would hurt brand perception or compliance. Michael had to be clear about what was actually happening: his team still writes every email. The humanization tool is a writing assistant that makes those emails more consistent and more human-sounding. That distinction matters.
He solved this by being transparent with his stakeholders about the process and the results. Open rates went up. Unsubscribes went down. Brand voice became more consistent. Those are facts that speak louder than concerns about whether a machine touched the copy.
Sustaining the Results
It’s now been a full year since Michael implemented the system, and the results have held. His open rates remain in the 50-54% range depending on the campaign. His unsubscribe rate has stayed low. Most importantly, his writers have capacity to think strategically about email marketing instead of just grinding out copy.
Michael reports that his team’s job satisfaction has actually improved. They’re doing more interesting work, strategic thinking, testing, segmentation analysis. The mechanical work of writing has been streamlined. That’s good for retention and for the quality of the work they’re doing.
Is This Right for Your Email Program?
This approach works best if you have: a defined brand voice, regular email sending (at least a few campaigns per month), a small team managing multiple campaigns, and the ability to review and refine AI output before sending.
If you’re already seeing open rate ceiling effects, or if you feel like your emails don’t sound consistent, this is worth exploring. The upfront investment in training the system and establishing brand voice guidelines pays dividends over months and years of campaigns.
The key is being intentional about the voice you want to establish. Humanization technology amplifies your voice, it doesn’t create one from scratch. If you know what you want your emails to sound like, this tool helps you sound that way consistently.
Start Improving Your Email Performance Today
Email remains one of the highest-ROI channels in digital marketing, but only if your audience actually engages with it. Humanization helps your emails sound like they come from a human who understands the reader, not a machine trying to optimize metrics.
Check out our use cases to see how other email and marketing teams are using humanization, and visit our pricing page to get started with a plan that works for your sending volume and team size.
