Your email list is only as powerful as the emails people actually open.
Read that again.
Because you can spend months building your list. You can pour money into Meta ads. You can write emails that would literally change someone’s life if they read them…
And none of it matters if your subject line sucks.
This is the part of email marketing most coaches get completely wrong. Not because they’re lazy. Not because they don’t care. But because no one has ever actually taught them how to write a subject line that makes someone stop scrolling and click.
So today we’re fixing that.
I’m going to walk you through everything I know about email subject lines after sending thousands of them, auditing hundreds more, and helping 550+ coaches inside HCA figure out why their open rates are tanking. By the end of this post, you’ll know exactly what to write, what to avoid, and how to test your way to 30%+ open rates week after week.
Let’s get into it.
Why Email Subject Lines Matter More Than You Think
Your email list is one of the most valuable assets you have as an online business owner. I talk about this constantly on my podcast. Your social media following can disappear overnight. Your Instagram account can get hacked. The algorithm can stop showing your posts tomorrow for no reason at all.
But your email list? That’s yours.
Which is why it kills me when I see coaches who’ve spent months or even years building a list of thousands of people… and then the emails they send get like a 12% open rate.
Because here’s what happens when no one opens your emails:
Your domain reputation tanks. Gmail and Hotmail start flagging your emails as low quality. More of your emails get routed to spam. Your open rates drop even further. And suddenly you’re in a death spiral where the people who WANT to hear from you can’t even find you in their inbox anymore.
It’s a mess.
But it’s a fixable mess. And the fix almost always starts with your subject lines.
Subject Lines Are the Single Most Controllable Lever for Open Rates
Yes, there’s tech stuff that matters too. Your DMARC, your DNS records, your domain authentication. (I did an entire podcast episode on email deliverability… Episode 325… go listen if you haven’t. It’ll save your inbox.)
But once all that tech stuff is set up once, you’re mostly done with it.
Your subject lines, on the other hand, are something you’re writing every single time you send an email. Which means they’re the one variable you have the most control over.
Think of your subject line like a storefront window. If someone walks by and the window is boring, dusty, or cluttered with junk, they keep walking. They don’t come inside. They don’t see the beautiful stuff you’ve set up.
Same thing with your emails.
The content inside might be life-changing. But if the subject line doesn’t catch their eye, they’ll never open it to find out.
What Your Email Open Rates Should Actually Be
Before we talk about how to write better subject lines, let’s talk about what you’re aiming for.
Because “good open rates” is subjective… and I have really high standards for my students.
The Benchmarks
Your freebie delivery email (the one that delivers the thing they opted in for): Should be at 50% open rate or higher. This person literally just put their hand up and said “yes, I want that thing.” If they’re not opening the email that gives them the thing they asked for, something is very wrong. Usually it’s lead quality or a bad subject line on the delivery email itself.
Your email nurture sequence (the 10-14 emails that go out after someone opts in): Aim for 40% open rates. These people are warm. They’re engaged. They just joined your list. This is when they’re the most interested in solving their problem.
Your weekly nurture emails: 30% and above. Below 25% consistently? We have a problem.
Now, if you’re sitting here reading this with open rates in the 15-20% range, please don’t panic. This is fixable. But you do need to start paying attention.
Track Your Open Rates (Seriously, Do This)
Get a spreadsheet. Every time you send a weekly email, log the subject line and the open rate. That’s it. That’s the whole system.
Inside HCA we give you the exact spreadsheets for this because tracking is how you figure out what actually works for YOUR audience. What works for mine might not work for yours. The only way to know is to watch the data.
If you’re getting 28%, fine. Not great, but fine.
If you’re getting 18%? That’s a five-alarm fire. Your domain reputation is about to take a hit. We need to fix this now.
Boring Subject Lines vs. Compelling Subject Lines
Here’s the thing most coaches don’t realize…
(Sorry, let me say that differently. I promised myself I wouldn’t use that phrase anymore.)
Most coaches write subject lines that sound like blog post titles, newsletter headers, or corporate memos. And those are the exact subject lines that get ignored.
Boring subject lines sound like this:
- Monthly Update
- Tips for Better Health
- My Top 5 Strategies for Weight Loss
- Weekly Newsletter: April Edition
- Important Information About Our Services
Do you feel compelled to open any of those? Me neither.
Compelling subject lines sound like this:
- what does a unicorn have to do with your sex drive?
- i effed up
- the one thing destroying your thyroid… not what you think
- did you get this?
- when I did this, everything changed
See the difference?
Compelling subject lines feel personal. They feel like a text from a friend. They’re a cliffhanger. They make you raise an eyebrow and think, “wait, what?”
They create what we call an open loop in the reader’s brain. Something that can only be closed by clicking to read the email.
The Best Test I Know for Your Subject Lines
Before you hit send on an email, ask yourself this one question:
Would I open this if it landed in my inbox?
And be honest. Like, really honest. Not “well my audience will probably open it because they love me.” But actually… would YOU click?
Because that’s your reader’s experience too.
Start paying attention to what you open in your own inbox. When you click an email, ask yourself why you clicked. Was it curiosity? A specific name you recognize? A one-word subject that felt weirdly personal? An urgent-sounding ask?
Your own behavior is data. Use it.
The 5 Types of Email Subject Lines That Get Opened
Okay, now let’s get into the actual strategies. These are the five types of subject lines I rotate through in my own email marketing, and they’re the same five types I teach inside HCA.
1. Curiosity Subject Lines
These are probably the most effective of the bunch. They present an intriguing question or statement and leave a knowledge gap the reader needs to close.
Examples:
- the one thing destroying your thyroid… not what you think
- what no one told you about your morning coffee
- why most coaches quit in year two (and what they miss)
The key with curiosity subject lines is they need to be relevant to the email content. Clickbait is fine. Clickbait is actually great. But bait-and-switch is gross. Don’t promise a unicorn and deliver a donkey.
Also… if you want to see masters of the curiosity subject line, go look at the Weather Network app. Their article headlines are clickbait gold. I get sucked in every single time. Learn from them.
2. Story Tease Subject Lines
These hint at a story inside the email without giving away the ending.
Examples:
- when I did this, everything changed
- I hit rock bottom and was blown away by what happened next
- how a single note led to an epic adventure
- the unexpected visitor that turned my world upside down
The biggest mistake I see with story emails is coaches giving away the lesson in the subject line.
Bad: “not detoxing is wrecking your thyroid” Better: “this simple thing is wrecking your thyroid”
The first one tells me the answer. There’s no reason to click. The second one makes me want to know what the simple thing is.
3. Organic Subject Lines
These look like they came from a friend or a family member. Native. Casual. Like a personal text, not a marketing email.
Examples:
- did you get this?
- oops, I made a mistake
- hey, can I ask you something?
- quick question
- this you?
Use these sparingly. Like… very sparingly. Maybe once every 2-3 weeks max. Because when you overuse them, people catch on and start ignoring them. They become ineffective fast.
I use these strategically when I really want someone to open an email. A good example is my post-launch “why didn’t you buy” survey. I usually just write “quick question” as the subject line and the email is literally one sentence asking why they didn’t buy. Works every time.
4. Personalized Subject Lines
These use the subscriber’s first name in the subject line.
Examples:
- Jane, I made this for you
- Jane, did you forget this?
- Jane’s worst mistake
- hey Jane, this reminded me of you
Effective in small doses. Overuse makes them feel robotic and fake. Nobody believes you wrote them a personal email when every single subject line starts with their name.
During a launch, I might use personalized subject lines more often. In weekly nurture? Maybe once or twice a month, max.
5. Authority Subject Lines
These lead with your credibility, proof, or expertise.
Examples:
- how I helped Chloe rid herself of eczema without drugs
- my 5 years as a weight loss coach taught me this
- 5 proven strategies to help you lose weight
- how dozens of my clients became success stories
These work best when you have a specific result or outcome to anchor to. Vague authority (“I’m an expert in health!”) falls flat. Specific authority (“how my client Sarah dropped 40 pounds without cutting carbs”) lands.
I use authority subject lines more during launches. In my weekly emails, I’m mostly leaning on curiosity and story tease.
Email Subject Line Don’ts
Okay, now let’s talk about what NOT to do. Because most coaches are doing at least two of these things right now without realizing it.
Don’t Use ALL CAPS
Using all caps in your subject line is a one-way ticket to the Gmail Promotions tab. It also feels like you’re yelling at people, which… not the vibe we’re going for.
Don’t Use Title Case for Every Word
You know what I’m talking about. The “My Top 5 Tips For Better Digestion” treatment. Title case signals “this is a blog post” or “this is a newsletter from a brand.” It doesn’t feel human. It doesn’t feel like something a friend would send you.
Capitalize the first word if you want. Or don’t capitalize anything at all. Sentence case and lowercase both work great. I tend to lean into lowercase because it feels more casual and conversational.
Don’t Overuse Emojis
Emojis are great for punctuating a joke or adding a little personality. But when you stack three or four of them at the start of a subject line, two things happen:
- Spam filters flag your email as low quality
- Your readers assume it’s AI-generated (because AI loves to overuse emojis)
One emoji max. Sometimes zero is better. Be strategic.
Don’t Write Subject Lines Like Blog Post Titles
Blog post titles are for Google. They’re for SEO. They’re for search engines that need clear keyword-based signals.
Subject lines are for humans. They’re for inboxes crammed with 200 other emails competing for attention. Different job. Different rules.
Don’t Over-Rely on Personalization
If every single email you send starts with “Jane, …” it stops feeling personal fast. It starts feeling automated. And automated is the opposite of what personalization is supposed to achieve.
Don’t Use Vague Filler
“Check this out”
“You won’t want to miss this”
“Something important inside”
These say literally nothing. They don’t create curiosity. They don’t promise value. They don’t give the reader any reason to click. Skip them.
Don’t Do Bait and Switch
If your subject line promises one thing and your email delivers something completely different, your open rate might spike once. But your trust with that reader is gone. And your future open rates will drop because they learned you can’t be trusted.
Clickbait is fine. Bait and switch is not. Know the difference.
The Research That Costs You Nothing
Want to know the best way to get better at writing subject lines?
Pay attention to your own inbox.
I’m serious. This is free research and it’s better than any copywriting course you could buy.
Start noticing which emails you open and which ones you delete without a second thought. When you click an email, ask yourself: “why did I click this one?” Was it the name of the sender? The curiosity in the subject? A specific phrase that caught your eye?
Screenshot the ones that make you stop scrolling. Build a swipe file. Study them.
Your own clicking behavior is the best data you’ll ever have on what works.
How to A/B Test Your Subject Lines
Most email marketing platforms (ConvertKit, ActiveCampaign, FG Funnels, and others) let you run A/B split tests on your subject lines. And honestly, this is one of the best habits you can build.
Here’s how it works:
You write two different subject lines for the same email. Your platform sends Subject Line A to 5% of your list and Subject Line B to another 5%. After a few hours, it picks the winner based on which got the higher open rate. Then it sends the rest of your list the winning subject line.
This is genius because it gives you two chances to hit a great open rate. And over time, you start learning what YOUR specific audience responds to.
I recommend A/B testing your weekly emails every single time.
The only time I don’t A/B test is during launches with tight time constraints, like reminder emails that need to go out at exactly 10am Pacific. In those cases, the split test takes too long and I just pick my best subject line and send.
But for your regular weekly nurture? Test every time.
Resending to Unopens (The Lazy Genius Strategy)
This is one of my favorite open rate hacks.
When you send a weekly email, after 48-72 hours you can resend that same email to everyone who didn’t open it… with a different subject line.
The email body stays the same. Only the subject line changes.
This alone can bump a 30% open rate up to 40% effectively. Because the people who didn’t open it the first time just missed it or the subject didn’t catch them. A different angle might land better.
A few rules:
- Wait at least 48-72 hours before resending
- Change only the subject line, not the email content
- Don’t resend more than once (twice max, and rarely)
- This is best for weekly nurture, not launch reminder sequences
Easy win. Almost no effort. Double your open rate potential.
Don’t Sleep on Your Preview Text
Quick note before we wrap up…
Preview text is that second line of text you see next to the subject line in most email inboxes. And most coaches totally ignore it.
Which is wild because preview text is basically a second subject line.
If you don’t write preview text, your email client just pulls the first line of your email body. Which usually ends up being something useless like “Hey Jane,” or “Can you see this email?”
Use your preview text strategically. Think of it as an extension of your subject line. Tease more. Add intrigue. Give a second hook.
I always write preview text for my emails. You should too.
The AI Hack I Use to Write Better Subject Lines
Okay, here’s a little trick I use that I’m pretty sure no one else is teaching.
When I’m working with a student whose open rates are inconsistent, I ask them to send me all their subject lines from the last 90 days along with their open rates. I dump the whole list into Claude and ask it to analyze the patterns.
And nine times out of ten, there’s a clear pattern.
The top performers are all curiosity-based. The bottom performers all sound like blog posts. Or the top performers are all one-word subject lines while the flops are all longer and more descriptive.
AI is wildly good at this kind of pattern recognition. Way better than staring at a spreadsheet yourself.
Here’s what you can do:
- Export your last 90 days of subject lines and open rates
- Paste them into Claude or ChatGPT
- Ask: “Can you analyze the commonalities between my top 20% and bottom 20% performing subject lines?”
- Take what it tells you and apply those patterns going forward
You can even take it a step further. Feed the AI your top-performing subject lines and ask it to write instructions for a custom GPT based on your personal winning patterns. Then anytime you write a new email, that custom GPT can pump out 10 subject line options based on what your specific list responds to.
That’s not magic. That’s just using tools smart.
What to Do Right Now
If you’ve made it this far, here’s what I want you to do this week:
First, pull up your last 10 weekly emails and check the open rates. If any are below 25%, make a note. Those are the ones we need to learn from.
Second, look at the subject lines of your top 3 and bottom 3 performers. What do the top ones have in common? What do the flops share?
Third, write your next email with one of the five subject line types in mind. Pick the one that feels most natural to start with… probably curiosity or story tease. Write two versions. A/B test them.
Fourth, bookmark this post so you can come back to it when you’re drafting.
And fifth, start paying attention to your own inbox. You are your own best research subject.
One Last Thing Before You Go
If you’re a health coach or wellness practitioner in the first 0-3 years of your business and you’re realizing your email marketing has been leaving money on the table… this is exactly the kind of stuff we work on inside HCA.
Not just subject lines. The whole system. Your email nurture sequence. Your weekly emails. Your sales emails. Your launch emails. The tech that makes sure all of it actually lands in the inbox.
Because an email list that converts is one of the biggest leverage points in your entire business. And most coaches are massively underusing theirs.
If that’s you, and you want help building an email system that actually brings in clients on repeat… the door to HCA is open.
Go apply. Let’s build you a business that doesn’t live or die by the Instagram algorithm.
Your future self (and your open rates) will thank you.
