I spent 20+ years leading marketing teams — American Express, Saks Fifth Avenue, Martha Stewart, and a few dozen others. Email marketing was a core competence. My teams drove tens of millions in revenue through it.
Then I started Theo Reads and began sending our own newsletter to romance and erotica readers, and discovered that romance and erotica readers are a different beast.
Our newsletter runs at roughly twice the publishing industry average open rate (sometimes higher). And it’s because we test subject lines, story descriptions, buttons and clicks maniacally. Here's what I've learned.
The #1 Test
Before you write anything, ask yourself: does this make someone feel something? Does it leave a question unanswered?
- If your subject line summarizes what's inside, rewrite it. You've answered the question before your reader asked it. They don't need to open.
- Keep it 40–55 characters. That's approximately what fits on a phone screen before the text cuts off. Front-load the hook. "Forbidden love in a royal court" shows the reader something. "This week's featured romance stories" shows nothing.
- Your subject line is written for a mobile inbox preview. Write for the scan, not the full read. Every word either earns its place or doesn't (and you lose your reader).
The Industry Benchmark
Publishing newsletters typically land between 20–30% open rates, according to iPost's 2025 email marketing benchmarks. (A note: Apple Mail Privacy Protection has inflated reported open rates since 2021 — some sources now show higher figures, but they include automatically-registered opens that don't reflect a reader actually choosing to open your email. The 20–30% range is the real baseline for meaningful engagement.)
The average click-through rate for publishing newsletters is 2–4%. That's what you're trying to beat.
When to send: Based entirely on our proprietary data (so the answer may be different for others), 8–9pm CT because it’s the sweet spot for all coasts in the U.S. - romance readers are overwhelmingly clustered in New York, California, Texas and Florida. At this time, they’re either already in bed, scrolling or on their way.
After 9pm CT, opens and clicks decline. Sunday and Friday evenings consistently outperform other days — if you're sending one email a week, those are your best windows.
Tools for Previewing Your Subject Line
A few options worth knowing:
- Email Tool Tester (emailtooltester.com/en/email-subject-lines-tester) — shows exactly how your subject line appears on iPhone, iPad, Android, and Samsung devices. Free. Useful to answer: does it get cut off before the hook?
- Litmus (litmus.com) — previews across 90+ email clients and runs spam checks, link validation, and accessibility tests. Comprehensive but paid.
- MailerLite's subject line tester (free) — checks length, readability, and whether you've used keywords that correlate with higher opens. Less visual, more of a quick sanity check.
Or you could just do what I do, which is eyeball subject lines manually. Or, send yourself a test email before sending the final out to the entire email list - this is a best practice anyway, as it allows you to test every link and make sure your images are rendering correctly.
The Formula
Every high-performing subject line does one of two things, or both:
The charged moment is the hook — a quote, a contrast, a genre signal, a cultural reference. Leaving it unfinished generates curiosity that makes the reader open. The five formulas below are all variations on this pattern.
5 Subject Line Formulas That Work for Theo Reads
Start in the middle of something. The reader's brain wants to finish it. You've created a gap they need to close.
From our own newsletter, in order of performance:
- "Spread your knees," he murmured quietly... — among our highest-performing subject lines ever
- "I desperately wanted to touch myself..." — strong performer
- "I will have you, in every way I can." — medium-to-strong
The line has to be genuinely good. A mediocre quote creates confusion, not curiosity.
The reader feels like an insider. Like this email was written for people who get it — not for a general audience.
- Eat, Pray, F***
- The Average Penis Size, According to Science
- Caution: Erotic espionage & VERY kinky gardening
The brain wants to understand the connection. It opens the email to find out.
- Americans are having less sex. Here are 3 free stories to help.
- Very Dark, Very Erotic (Danger Ahead)
For romance and erotica specifically, the most honest subject line is often the most effective. Readers who want what you write are looking for it. Give them the signal.
- Steamy Gay Romance Stories
- Spicy Lesbian Romance
Relevance creates urgency that a generic newsletter can't fake.
- Free Friday Reads (48 Hours Only).
Note: We’ve moved away from this subject line because we don’t just want the free reader, we also want the reader who is willing to pay. And, this subject line in particular degraded in performance within weeks — so, my advice would be not to use the same subject line every week, never mind what the newsletter experts say. - I love you. Here's a free story. (Valentine's Day)
- Skip the game. Read this instead. (Super Bowl weekend)
What Doesn't Work
- "Discover," "explore," "find out." These signal marketing copy, not a real person talking to another real person. Your reader is not a target. They're someone who might want to read something tonight.
- Summarizing what's inside. If they already know, they don't need to open.
- FREE in all caps. Spam trigger, full stop. Lowercase "free" is fine.
- Over-explained setups. "In this week's email, I'm sharing six stories about forbidden love across different subgenres..." Delete it. Start with the hook.
The Counterintuitive Truth About Emojis in Subject Lines
Most email marketing advice tells you to use emojis in subject lines. Our data suggests otherwise.
For us, no-emoji subject lines consistently outperform emoji subject lines in click-through rate. The highest-performing subject lines we've sent include some with no emoji at all.
There's also a deliverability consideration worth keeping in mind: romance and erotica content already faces higher spam filter sensitivity than most categories. Adding emoji to the mix may compound that risk, though the more certain finding is simply that they don't help performance. Save them for preview text, where they do show a small measurable lift.
When you do use an emoji, placement matters. An emoji in the middle of a subject line (used sparingly, in the right context) outperforms an emoji at the end. End placement has become reflexive and readers barely register it. Mid-placement creates visual interruption, which creates a moment of attention.
- The emojis that appear most frequently in high-performing romance and erotica newsletters: 🍒 🖤 👄 🐺 🐉 🔥
- The ones that don't appear in high performers: ✉️ 🌸 ✨. Soft and generic don't land.
Preview Text: The Second Line
Preview text is what readers see next to your subject line in the inbox. It does a different job. Subject and preview should never repeat the same information.
Under 90 characters. Never start with "In this week's email." Never list story titles. One emoji in preview text adds a small but measurable positive effect on click-through rate — use it once, placed intentionally.
Three techniques:
- Escalation — preview raises the stakes:
Subject: "Spread your knees," he murmured quietly...
Preview: I probably shouldn't start an email like that, but here we are. - Pivot — preview contradicts or reframes:
Subject: Americans are having less sex. Here are 3 free stories to help.
Preview: The data is depressing. The stories are not. - Continuation — preview finishes the sentence:
Subject: "I desperately wanted to touch myself..."
Preview: ...and that's before the vitals check gets out of hand.
Four Ways to Think About Your Subject Line
- As a reader: Give me a reason to click before I put my phone down. I want to feel something in the first ten words. I have 47 open tabs and three unfinished series. Make me choose your email.
- As a data analyst: The subject line gets the open. The content gets the click. Those are two separate decisions. When subject line, preview text, and email content are tonally aligned, click-through rate climbs. When they're mismatched, readers open and don't click. You got the open and lost the sale.
- As a psychologist: Your reader is decision-fatigued. The subject line that does the least work for the reader — leaves the most question unanswered — wins. The reader's job is to close the gap. The more work you do for them in the subject line, the less reason they have to open.
- As an email expert: You're writing for a mobile inbox preview of approximately 40 characters. Write for the scan, not the full read. Every character is either earning attention or wasting space.
What Makes a Romance and Erotica Newsletter Look Like Spam
Romance and erotica authors face higher spam filter sensitivity than almost any other newsletter category. Understanding this isn't optional — it's the difference between a newsletter that reaches readers and one that disappears into a folder nobody checks.
Avoid these in subject lines and body copy:
- FREE in all caps
- "You won't believe"
- "Act now" / "Limited time offer"
- "Click here" as the actual link text
- "This is not spam" (the filter is not reassured)
- "Guarantee" or "guaranteed"
- "No strings attached"
- Dollar signs in subject lines
- Excessive exclamation points
- All-image emails with no text — spam filters can't read images
- Text-to-image ratio that's too low
- More than 5–7 links in a short email
- No physical mailing address — legally required for commercial email in most countries
- No unsubscribe link in marketing emails — legally required, and missing it can get your domain blacklisted
Gmail, Outlook, and Apple Mail maintain a reputation score for your sending domain. It's invisible to you but determines whether your emails reach inboxes or the spam folder.
The most practical protection: one-click unsubscribe, clearly visible, in every marketing email. Most readers mark email as spam because unsubscribing felt too hard. Make it easy. A lost subscriber you can recover from. A spam complaint damages your entire list.
One more thing: periodically ask your readers to move your email from their Promotions tab to their main inbox. Something like: "Quick favor — if this landed in your Promotions tab, drag it to your main inbox and hit 'Do this for all future emails.' It means you'll actually see it." Use this once or twice a year, not every email.
Your email platform has a setting called "email authentication" or "domain authentication" — usually under Settings or Sending Domains. If you haven't set it up, do it now. It takes about 30 minutes and tells Gmail, Outlook, and Apple Mail that your emails are legitimate, which means more of them reach inboxes instead of spam folders. Every major platform (Mailchimp, Kit, Beehiiv, Ghost, Postmark) has a step-by-step guide. Search "[your platform name] domain authentication setup" and follow it.
Explicit language in subject lines and body copy triggers spam filters regardless of context. It doesn't matter that you're writing consensual erotica for adults who opted in. The filters don't read that carefully.
What works: strategic masking. s*x, f**k, and similar variations clear most filters while still communicating your heat level to readers. Full censorship loses the signal. Spelling it out risks flagging. Test it on your own list — different email platforms respond differently, and what works in one may not work in another.
Frequently Asked Questions
What is a good open rate for a romance or erotica author newsletter?
Publishing newsletters benchmark at 20–30% for meaningful engagement (iPost, 2025). Above 30% is solid. Consistently above 35% suggests strong subject line performance and an engaged list.
What is a good click-through rate for a romance newsletter?
The publishing industry average is 2–4%. Romance and erotica newsletters with strong subject lines and story descriptions can significantly outperform this. Above 8% is exceptional.
Should romance and erotica authors use emojis in email subject lines?
No. Spam filters specifically penalize romance and erotica senders for emoji in subject lines. The counterintuitive finding: no-emoji subject lines outperform emoji subject lines in click-through rate. Use one emoji in preview text instead, where it adds a small positive effect without the deliverability risk.
When is the best time to send a romance newsletter?
8–9pm local time for your readers. For US lists, that's 8–9pm CT — after 9pm, both opens and clicks decline. Romance and erotica readers are in bed and scrolling. Sunday and Friday evenings are the strongest days.
Why does my newsletter keep going to spam?
The most common causes: no unsubscribe link in marketing emails, spam complaint rates above 0.1%, no SPF/DKIM/DMARC authentication on your sending domain, or spam trigger words in the subject line or body copy. Explicit content creators face elevated filter sensitivity across all major platforms.
What words should I avoid in romance newsletter subject lines?
FREE in all caps, "act now," "limited time," "click here" as link text, excessive exclamation points. For explicit language, masked versions (s*x, f**k) outperform both fully censored and fully spelled-out versions in most deliverability tests.
Does subject line length matter?
Yes. 40–55 characters. Most phones cut off around 40 characters. Front-load your strongest word. A sentence that ends mid-thought can work in your favor — but only if the first 40 characters already have the hook.
What emojis work best in romance and erotica newsletters?
In high-performing romance and erotica newsletters: cherry, black heart, lips, wolf, dragon, fire. Avoid soft or generic emojis (envelope, flowers, sparkles) — they don't correlate with strong performance. And when you use one, put it in the middle of the subject line or in preview text, not reflexively at the end.
Questions? Write to us at realhumans@theoreads.com. We read everything.