Can AI-generated email content hurt your deliverability?
Michael Ko
Co-founder & CEO, Suped
Published 2 Jul 2025
Updated 21 Aug 2025
11 min read
The rapid adoption of AI tools for content generation has brought about incredible efficiencies for email marketers. It allows us to draft subject lines, write entire email bodies, and even personalize content at scale with unprecedented speed. Yet, with this power comes a new set of challenges, particularly concerning email deliverability. While AI can undoubtedly enhance your email campaigns, it also introduces potential pitfalls that could unintentionally lead your messages straight to the spam folder or onto a blocklist.
My concern, and what I've seen firsthand, is that relying too heavily on unedited AI output can make emails appear generic, repetitive, or even incomplete. These subtle cues, or sometimes glaring errors, can be picked up by spam filters and, more importantly, by your recipients, impacting engagement and ultimately, your sender reputation. It's crucial to understand how AI-generated content is perceived by both automated systems and human recipients to maintain strong email deliverability.
How AI can inadvertently hurt deliverability
Generic and repetitive patterns
One of the most common issues with raw AI-generated content is its tendency to produce predictable patterns. AI models are trained on vast datasets, and if not prompted carefully, they often default to common phrases, sentence structures, and a somewhat uniform tone. This can lead to emails that lack a unique brand voice or sound too similar to other AI-generated content saturating inboxes.
Spam filters, particularly those powered by advanced machine learning, are constantly evolving to detect these patterns. If a significant volume of emails from your sending infrastructure (IP or domain) exhibits characteristics commonly associated with automated or low-quality content, it can raise red flags. This can lead to your emails being flagged as spam or even your domain ending up on a blacklist (or blocklist).
Beyond the technical filtering, generic content also impacts recipient engagement. If an email feels impersonal or uninspired, recipients are less likely to open it, click through, or even remember your brand. Low engagement metrics—such as low open rates, low click-through rates, and high unsubscribe rates or spam complaints—signal to mailbox providers that your content isn't valuable, further harming your sender reputation. A study found no significant direct impact of AI-generated content on spam folder placement, regardless of the sender's domain or recipient's provider. However, this study also highlights the importance of content personalization and its role in avoiding spam placement, a key area where AI can either help or hinder depending on its application. You can review the full research on AI's impact on email deliverability.
The AI content paradox
While AI can generate high-volume content, it often lacks the human touch that fosters genuine connection. This can result in lower engagement rates, which indirectly signals to mailbox providers that your content might be irrelevant or unwanted.
The importance of human review and ethical AI use
Human oversight remains essential
Despite AI's capabilities, human oversight remains critical. The example from the Slack thread about AI leaving behind its instructional prompts in live emails highlights a key risk. These "Let me know if you'd like it to sound more energetic..." type of phrases are clear indicators that the content wasn't fully reviewed by a human. Such errors not only damage brand credibility but can also trigger spam filters that look for signs of automated or careless generation. This also applies to things like emojis and specific spam words. Learn more about how to prevent spam words from affecting email deliverability.
Mailbox providers are increasingly sophisticated in identifying content generated without human refinement. They analyze various elements beyond just keywords, including formatting quirks, overuse of certain punctuation (like excessive dashes), and a lack of conversational flow. An email that looks and feels machine-generated is more likely to be diverted to the junk folder, regardless of your sender reputation.
The danger lies in the ease with which AI can produce content. Marketers might be tempted to prioritize quantity over quality, sending out a high volume of emails with minimal human review. This approach quickly backfires. A poor user experience, leading to higher unsubscribe rates and increased spam complaints, is a direct signal to mailbox providers that your emails are not welcome. This negative feedback loop severely impacts your sender reputation, making it harder for all your emails to reach the inbox. We've compiled a full guide to help you prevent emails from going to spam and how to fix it.
Problem: Over-reliance on AI
Content generated by AI often lacks unique brand voice and human nuance, making it sound generic. Without proper oversight, AI tools can produce repetitive phrasing or even include instructional prompts within live emails, signaling automated or unreviewed content to recipients and spam filters. This leads to lower engagement, increased complaints, and potential blocklisting, ultimately harming sender reputation.
Solution: Human-in-the-loop approach
Integrate AI as a powerful assistant, not a replacement for human creativity and review. Human editors should refine AI output to ensure it aligns with brand voice, feels authentic, and is free of errors. Focus on using AI for initial drafts or personalization at scale, but always apply critical human judgment before sending. This hybrid approach optimizes efficiency while safeguarding deliverability and recipient trust. This approach can also involve ensuring proper AI personalization for cold emails
Strategic uses of AI for deliverability
Leveraging AI for better deliverability
It's not all doom and gloom, however. When used strategically, AI can significantly improve your email deliverability. The key lies in understanding where AI excels and where human intervention is indispensable. AI can be a powerful ally in tasks that benefit from data analysis, pattern recognition, and optimization.
For example, AI can analyze vast amounts of recipient data to help you segment your audience more effectively, identify optimal send times, and even predict which subject lines are most likely to resonate. This level of personalization and optimization leads to higher engagement rates, which in turn boosts your sender reputation. A high sender reputation is the cornerstone of good deliverability, ensuring your emails reach the inbox rather than the spam folder.
AI can also assist in A/B testing variations of email content to identify what performs best. This iterative optimization, driven by AI's analytical capabilities, can lead to continuous improvements in open rates, click-through rates, and conversion metrics. The goal is to make your emails more relevant and engaging for your audience, which is precisely what mailbox providers want to see. This supports better inbox placement when AI-crafted content is clear, relevant, and diverse.
Furthermore, AI can help in identifying potential spam triggers in your content before you hit send. This includes detecting high image to text ratios, analyzing sentence complexity, and even checking for characteristics that might lead to a blacklist or blocklist inclusion. Think of AI as an advanced deliverability assistant, helping you refine your content to meet the stringent requirements of modern spam filters. This proactive approach significantly reduces the risk of deliverability issues.
AI in action: improving deliverability
Gmail and other mailbox providers utilize AI for spam detection. By using AI to optimize content for engagement and relevance, you can positively influence how your emails are perceived and improve your deliverability metrics. This includes tailoring content to individual preferences.
Maintaining quality and reputation
Best practices for using AI in email content
To harness the benefits of AI without risking your deliverability, adopt a disciplined approach:
Humanize and refine: Never send AI-generated content without thorough human review and editing. Ensure it matches your brand's unique voice and tone. Remove any obvious AI remnants, like instructional phrases or repetitive patterns. This is crucial for avoiding spam traps or ending up on a blocklist.
Focus on personalization: Use AI to personalize content based on recipient data, but ensure the personalization feels genuine and not overly automated. Generic or irrelevant personalization can backfire. This can include using AI for AI email warmup tools for cold outreach.
Vary content and structure: Avoid consistently using the same AI prompts or templates, as this can lead to predictable content. Experiment with different AI models or prompting techniques to create diverse email styles and structures. Remember that email templates can trigger spam filters.
Monitor engagement metrics: Regularly track your open rates, click-through rates, unsubscribe rates, and spam complaint rates. These metrics are crucial indicators of how your content is performing and its impact on your sender reputation. If you see negative trends, it might be time to reassess your AI content strategy. Monitor your blocklist status to ensure you are not on a blacklist (or blocklist).
Conduct A/B tests: Test different versions of AI-generated content against human-written content or different AI variations. This helps you understand what resonates best with your audience and performs optimally in terms of deliverability. Your email deliverability tester can help.
The evolving landscape of AI and deliverability
Technical considerations and AI
While AI mainly impacts content quality, its indirect effects on technical deliverability are significant. Poor content leads to low engagement, which can cause your sending domain to be blacklisted. This emphasizes the need for a comprehensive approach to email security and deliverability. You can learn more about DMARC, SPF, and DKIM.
AI's role in the future of email deliverability is a topic I often reflect on. As mailbox providers like Google and Yahoo continue to leverage AI for spam filtering, email marketers must adapt. This means focusing on authentic content, even if initially drafted by AI. The key is to refine, personalize, and ensure every email adds value to the recipient. Ultimately, the best defense against spam filters is to send emails that people genuinely want to receive. This will also prevent images linked from your domain in spam emails from causing deliverability issues.
Monitoring your domain's reputation and understanding why your emails might be landing in spam is more critical than ever. Tools that provide insight into your sender reputation, DMARC reports, and blocklist status are indispensable. Staying informed about the latest deliverability trends and algorithm changes, including the impact of AI, is essential for long-term email marketing success. Ensure you understand what happens when your domain is on an email blacklist (or blocklist).
Views from the trenches
Best practices
Always include a human review stage for all AI-generated email content to ensure authenticity.
Test different AI prompts and models to avoid repetitive content and maintain varied email styles.
Regularly monitor your email deliverability metrics, like open rates and spam complaints.
Use AI to analyze recipient data for deeper personalization, improving relevance and engagement.
Common pitfalls
Sending unedited AI output directly, including instructional prompts or repetitive phrases.
Over-relying on AI for bulk content creation without humanizing the tone and style.
Neglecting to monitor engagement metrics, missing early signs of deliverability issues.
Using generic AI templates that make emails look too automated or uninspired.
Expert tips
Integrate AI as a smart assistant, not a full replacement, for your content creation process.
Focus AI on data-driven optimizations like send times and segmentation, where it truly excels.
Educate your team on ethical AI use and the importance of human oversight in content review.
Utilize AI to identify potential spam triggers in your draft emails before sending.
Expert view
Expert from Email Geeks says that overusing em-dashes, bolded words in bullet points, and emojis in AI-generated content often leads to unsubscribes, as it makes emails appear less genuine.
2024-07-01 - Email Geeks
Marketer view
Marketer from Email Geeks says they almost sent a newsletter with "Ask ChatGPT" at the end of a preheader after using AI to summarize articles, highlighting the need for careful review.
2024-07-02 - Email Geeks
A balanced approach to AI-generated content
The advent of AI in email marketing is a double-edged sword. While it offers unparalleled efficiency and personalization capabilities, it also demands a higher degree of vigilance and human discernment. Unedited, generic, or poorly integrated AI content can indeed harm your email deliverability by triggering spam filters and diminishing recipient engagement, leading to a damaged sender reputation and potential blocklisting.
However, when approached strategically—with robust human oversight, a focus on true personalization, and continuous monitoring—AI can become a powerful asset for improving your email deliverability. The future of email marketing with AI isn't about fully automating content creation, but rather about creating a symbiotic relationship where human creativity and AI efficiency work together to deliver highly engaging and impactful messages that consistently reach the inbox.
Gmail and other mailbox providers utilize AI for spam detection. By using AI to optimize content for engagement and relevance, you can positively influence how your emails are perceived and improve your deliverability metrics. This includes tailoring content to individual preferences.
Google and 
Yahoo continue to leverage AI for spam filtering, email marketers must adapt. This means focusing on authentic content, even if initially drafted by AI. The key is to refine, personalize, and ensure every email adds value to the recipient. Ultimately, the best defense against spam filters is to send emails that people genuinely want to receive. This will also prevent images linked from your domain in spam emails from causing deliverability issues.
