Email has always been the workhorse of digital marketing. Flashy social media campaigns come and go, but email—despite being called “dead” more times than I can count—continues to quietly drive conversions, nurture leads, and maintain customer relationships.
But now there’s a twist in the story. Artificial intelligence has entered the inbox. Instead of human copywriters toiling over subject lines and body text, many marketers are handing that responsibility over to machines.
Which raises the big question: how does this shift actually affect open rates and conversions? Are AI-crafted emails better, worse, or just… different?
The Rise of AI in Copywriting
The last few years have seen an explosion in AI tools designed to help with content creation. From Jasper to Copy.ai to ChatGPT, marketers now have entire platforms promising subject lines, taglines, product descriptions, and yes, emails—delivered instantly.
The appeal is obvious. Writing is time-consuming. Testing is exhausting. And budgets are tight. If AI can generate email copy at scale—tailored, data-driven, endlessly customizable—why wouldn’t brands at least try it?
And they are trying it. A 2023 Salesforce survey reported that 68% of marketers are already using AI for content personalization, and email is one of the most common channels.
But the question isn’t just who’s using it. It’s whether can AI copywriting really move the needle.
Subject Lines: The Gatekeepers
Every email campaign lives or dies at the subject line. You can craft the most persuasive body copy in the world, but if no one opens the email, it doesn’t matter.
This is where AI has made some of its biggest impact. Algorithms can generate dozens of subject line variations in seconds, each tuned to maximize curiosity, urgency, or personalization.
And unlike human writers, AI can feed those directly into A/B testing with live audiences to quickly determine which performs best.
Results? They’re impressive, at least on paper. Phrasee, a company specializing in AI email optimization, reported open rate improvements of up to 10% for clients across industries.
That might not sound massive, but in the world of email marketing, even a 2% increase can translate into thousands of extra clicks and conversions.
So yes, AI-written subject lines are often catchier—or at least more effective—than human ones.
But effectiveness doesn’t always equal authenticity, and that tension runs through the entire conversation.
AI-Generated Sales Emails: Efficiency vs. Connection
It’s not just subject lines. Entire AI-generated sales emails: introductions, pitches, follow-ups, calls-to-action—are being produced by machines.
On one hand, this is a dream for sales teams. Instead of spending hours crafting outreach, they can scale campaigns effortlessly.
AI tools can even analyze recipient data to adjust tone: more formal for executives, more casual for younger audiences.
But here’s the flip side: these emails often feel formulaic. I’ve seen AI outreach that hit all the right beats—polite opener, value proposition, clear CTA—and yet I knew, instantly, that no human wrote it.
It lacked warmth. It lacked that little spark of personality that makes you think, hey, this person actually cares about me, not just my inbox space.
And while AI may increase the volume of responses initially, over time, audiences may grow weary of emails that all sound eerily similar.
The Dark Side of AI Copywriting
Now, we can’t avoid talking about the dark side of AI in email.
When algorithms are optimized purely for engagement, they tend to lean into manipulative tactics. They overpromise. They create artificial urgency. They push the boundaries of clickbait.
Sure, open rates go up in the short term. But at what cost? If audiences begin associating your brand with gimmicky or misleading emails, you lose trust—and once trust is gone, no AI tool can buy it back.
There’s also the problem of sameness. If every company is using the same handful of AI tools, trained on the same data, aren’t we at risk of filling inboxes with identical voices?
“Your exclusive offer awaits,” “Don’t miss this,” “Last chance!”—these phrases already blur together. Multiply them by AI scale, and the fatigue could be overwhelming.
Conversions: The Real Bottom Line
Here’s where the rubber meets the road. It’s not enough to boost open rates if conversions don’t follow.
Studies here are mixed. Some marketers report higher click-through and conversion rates from AI-crafted copy, while others say performance plateaus.
Why? Because conversions depend on more than words. They depend on the offer, the product, the landing page, the trust built with the audience.
AI can help with optimization, but it can’t fix a weak value proposition or a clunky checkout process. In fact, over-reliance on AI copy might even hurt if audiences sense insincerity.
People don’t want to feel like they’re just data points in a machine’s prediction model. They want to feel like someone thought about them.
Can AI Copywriting Replace Humans?
This is the question marketers whisper at conferences but rarely say out loud. The truth? Not yet.
Yes, AI can draft faster, test quicker, and even outperform in some scenarios. But it struggles with empathy, humor, cultural nuance, and storytelling—the very things that make email marketing feel personal.
And let’s be honest: some of the best-performing emails in history were unconventional, even messy. They broke rules. They surprised people.
They connected on a deeply human level. AI isn’t good at breaking rules—it’s good at following patterns.
So while AI will transform copywriting, I don’t see it replacing human creativity. I see it as a powerful assistant—an amplifier, not a replacement.
Hybrid Models: Best of Both Worlds
In my view, the smartest marketers won’t ask whether AI or humans are “better.” They’ll use both.
AI can churn out endless subject line variations. Humans can pick the one that feels authentic. AI can draft a hundred follow-ups.
Humans can refine them for empathy and tone. AI can analyze engagement patterns. Humans can interpret them in cultural context.
It’s not “AI versus humans.” It’s “AI plus humans.” That’s where the real magic—and sustainable conversions—will happen.
When AI Works Best
Through observation and experience, here are the situations where AI shines:
- Transactional emails. Receipts, confirmations, updates—AI can optimize wording for clarity and engagement.
- Large-scale outreach. For high-volume campaigns, AI saves time without sacrificing too much quality.
- Testing environments. AI thrives in A/B testing with subject lines, CTAs, and tone, where quick iterations are key.
But when the stakes are high—product launches, relationship-driven outreach, brand storytelling—human creativity should still lead.
Ethical Considerations
We can’t ignore the ethical layer. Who owns the rights to AI-written copy? If a brand uses AI to generate emails that closely resemble a competitor’s style, is that plagiarism?
There’s also transparency. Should companies disclose when their emails are AI-written? Audiences may demand that clarity in the future. And regulators may not be far behind.
The Human Factor: Why Empathy Still Wins
At the end of the day, marketing is about people. And people crave connection.
I remember receiving an email from a small business during the early days of the pandemic. It wasn’t polished. It wasn’t optimized. It was a heartfelt note from the owner, thanking customers for their support during uncertain times. It moved me in a way no algorithm could.
That’s the risk of over-automation. If we let AI handle every interaction, we lose the messiness, vulnerability, and warmth that make communication human.
My Final Take
So, how does AI copywriting affect email open rates and conversions? It helps. It can boost opens, streamline workflows, and even improve click-throughs. But it also risks eroding authenticity if left unchecked.
The best future, I think, is one where AI does the heavy lifting but humans still provide the heart. AI handles the patterns. Humans provide the soul.
Because while AI might nudge someone to open an email, it’s still human connection that convinces them to act.
