21 Cold Email Subject Lines to Boost Open Rates, Spark Curiosity, Stop Unsubscribes and Keep Your Communications Fresh | SizzleForce, Inc.

21 Cold Email Subject Lines to Boost Open Rates, Spark Curiosity, Stop Unsubscribes and Keep Your Communications Fresh

One pillar of modern marketing is emailing prospects, but you won’t get anywhere if your sales emails and cold email subject lines aren’t up to par. Subject lines are your first impression. Your chance to grab attention. And an opportunity to share that you know your stuff. Crafting a good one is part strategy, part creativity, with a dash of personality thrown in for good measure. When done well, your recipients can’t help but open the shiny new message waiting for them in their inbox. 

But what about emailing people you don’t really know or you’ve never connected with? Enter the well-written cold email subject line. 

Cold email subject lines have two jobs: 

  1. Grab attention
  2. Don’t be spammy

Here at SizzleForce Marketing, we like to run our recommendations through a five-step process for maximum clickability. Our process looks like this: keep it short and sweet, use personality, communicate a sense of urgency, add value, and avoid clickbait.

It almost becomes second nature once you practice it a few times, but to get you started, we’ve compiled 21 of our favorite cold email subject lines for you to test out the next time you need to make a connection.

21 Cold Email Subject Line Examples to Get You Started

  1. I could really use your help
  2. Only X spots left
  3. Doing a little experiment
  4. Do we have this in common?
  5. Quick questions about [industry]
  6. How can I help?
  7. I have an idea you might like…
  8. Can I get your feedback on this?
  9. How to start your [goal]
  10. Before it’s too late…
  11. Have you tried [popular item for industry]?
  12. [Industry] trends you’re going to hate
  13. [Industry] trends you’re going to love
  14. Almost all [profession/job title] get this wrong
  15. Are you making this mistake?
  16. Steal this idea (it’s our favorite!)
  17. Are we still on for 2 pm?
  18. Before you [typical industry task], read this
  19. You know you work in [industry] when…
  20. Let me tell you an embarrassing story
  21. The customer isn’t always right

I could really use your help

Usually, people like to be helpful (or at least rarely turn down an opportunity to show off their expertise!). This general cold email subject line works for just about any industry and any professional relationship. Add in a customized first name at the end of it, and the recipient might question, “How do they know me? And what do they need help with?”

Only X spots left

Perfect for increasing open rates and event attendance, a cold email subject line that shares how much availability is left taps into the recipient’s FOMO (fear of missing out) and creates urgency to take action. And you can modify it to fit just about any business need or event! Don’t believe me? Here are just a few examples:

  • Only 5 VIP tickets left
  • Only 2 spots left for February
  • Only 10 seats left for our beginner’s training
  • Only 3 slots left on our delivery route

Pro tip: If your digital event doesn’t technically have a limit, build one in and make those who sign up feel extra special for being a part of it.

Doing a little experiment

Appeal to your contact’s curiosity by teasing an experiment in your cold email subject line. And you don’t even have to be a scientist or like data to do this! After all, aren’t all cold emails an experiment to see who will open it and take action? Just make sure you mention what kind of experiment you’re doing in the body of your email for consistency. 

Some examples of experiments you can say you’re performing:

  • Testing who prefers cold emails vs. cold calls
  • Seeing who appreciates a follow-up because life is busy
  • Determining if you are doing the right kind of outreach

Do we have this in common?

Sometimes I like to think of my inbox as a cocktail party (if only to give me an excuse to put on cute shoes!). But, seriously, if you have my work email address, there’s a chance we have something in common. This cold email subject line is friendly and piques curiosity. It also gives you a foot in the door to understanding your prospect’s personality and interests. Inside the email, you can ask about location, approaches to work/life balance, or something general in their industry.

Quick questions about [industry]

This “quick question” approach appeals to that inner desire to help others we talked about earlier. Plus, it shows you’ve done your research about the person you’re contacting. Nothing adds credibility to a cold email quicker than proving you’re not mass emailing anyone you could connect with on LinkedIn. A word of warning though: don’t undo the goodwill you built in the subject line by getting their first name wrong in the body of your email.

How can I help?

Let’s flip the roles a bit and offer our help instead. Chances are you’re reaching out to them because you believe your product, service or expertise can make their lives easier. Creating a cold email subject line like this one gives you a chance to empathize with their situation and shows that you’re willing to listen. Consider pairing this one with a free consultation or resource if possible.

I have an idea you might like…

Similar to offering your help, this cold email subject line sets you up to offer insight or assistance. But it also appeals to the recipient’s curiosity. Think about your own relationships. Aren’t you the least bit curious when a friend texts you “So, I had an idea…”? Create the same excitement with this kind of broadly appealing intro.

Can I get your feedback on this?

You’ve probably figured out by now that people love to share their wisdom and expertise. This cold email subject line sets the recipient up to help, offer insight or be brutally honest. And, really, either of those options can give you something to go on to pitch your services or products.

How to start your [goal]

Many people are thinking about their progress at the beginning of a year, a quarter or a month, either professionally or personally. If your product or service helps people meet some sort of measurable goal, try using this cold email subject line during an optimistic time frame in the industry you serve. Here are a few ideas:

  • How to start your fitness routine (send at the beginning of the year)
  • How to keep better track of your tax documents (send around April 15)
  • How to build your social following (send at the beginning of any month)

Before it’s too late…

As I mentioned before, people do *not* like missing out on things. Sending out a “Before it’s too late…” email gives recipients a heads up to get in on the action and can often be seen as a kindness. But use it sparingly, with warmer leaders or with someone you’ve made previous contact with in some capacity as it’s right on the line of being spammy.

Have you tried [popular item for industry]?

Whether you’re selling products, services or just making connections, throwing out this cold email subject line can work for you in so many ways. First, it gives you an opportunity to show you know their industry. Second, it helps you make timely connections especially if you’re asking about a niche item or trend. Finally, it gives you a genuine way to talk about your business.

And if all else fails (and you have a budget!), you can send them the item as a gesture of goodwill.

[Industry] trends you’re going to hate

It’s not a scientific study, but in a cursory check-in with my team, I discovered that half of us would click on this kind of cold email subject line out of curiosity and half of us would click on it just to prove we don’t hate whatever trends are mentioned. Chances are, something like this will work for you, too. Either way, this gives you a way to add value by rounding up some trends for the industry you serve and start a conversation.

[Industry] trends you’re going to love

You saw this one coming, didn’t you? If your audience doesn’t respond well to a strong word like “hate,” pivot and offer trends that they won’t be able to resist. Plus, this approach will take a little less time to send out. You just have to round up a few trends that work but aren’t necessarily controversial. 

Almost all [profession/job title] get this wrong

Are you sensing a theme here? Curiosity marketing is a powerful player in getting you in front of the people who need you. And what better way to pique someone’s curiosity than to make them question if they’re getting something wrong in their job. I recommend keeping this email full of value and ways you can help course correct whatever flaw you’re pointing out.

Are you making this mistake?

Similar to the cold email subject line above, this one appeals to that fear of missing out. Since this one is less general, it could easily transition into feeling like you’re pointing fingers at someone for doing something wrong. Use caution and empathy if you choose an approach like this.

Steal this idea (it’s my favorite!)

Who doesn’t love someone who’s trying to make things easier?! This cold email subject line is one of my favorites because it’s all about adding value to the reader while building your credibility. And you can go as broad and general or as industry-specific as you want. Here are a few general ideas you can base your email around:

  • A social media caption prompt
  • A morning routine to try
  • An icebreaker game for new clients

Are we still on for 2 pm?

The whole point of this cold email subject line is to grab their attention, but you have to use the content of your email to keep it. They might stop and question if they have a meeting at 2 pm, then open your email. From there, you want to pack as much irresistible value into the first few lines that they can’t help but request a call.

Before you [typical industry task], read this

This option is what I like to think of as a shapeshifter. You can use it to pique curiosity, tap into FOMO, or add incredible value. It’s all in how you use it and how you position yourself. Here are a few ways you can use it:

  • Before you file your taxes, read this
  • Before you make your next hire, read this
  • Before you submit your next report, read this
  • Before you respond to that complaint, read this

You know you work in [industry] when…

Nothing quite compares to the feeling of being understood. That’s why I think meme accounts on Instagram are so successful. Everyone loves relatably and knowing they aren’t alone. That’s the inspiration behind this cold email subject line. You can spin the body of your email to be hilarious or empathetic, but either way, you will come across as relatable. That’s a win in my book.

Let me tell you an embarrassing story

Another way you can approach being relatable is by sharing an embarrassing story. Now, you don’t have to undermine your credibility, but this cold email subject line gives you an opportunity to build trust, display your determination and show you don’t take yourself too seriously all in one go.

The customer isn’t always right

My final suggestion for a subject line is to take a piece of well-known (and loved) advice and turn it on its head. This adds a friendly shock-and-awe factor that you can’t help but click to learn more. Here are some examples of other go-to advice you can flip:

  • You shouldn’t turn your passion into a business
  • It’s not always about the money
  • Don’t fake it until you make it

You can absolutely increase your open rates using these engaging cold email subject lines! But if you’d like some help with your overall email strategy, Team SizzleForce is happy to help. Schedule a free consultation with our email marketing team to start developing an email strategy that works for your business, no matter how hot or cold your leads are.

Scroll to Top

Leanne King

Digital Marketing Strategist & AI Content Specialist
Super Power: Transmutation: Turning Cool Ideas into Even Cooler Content

Sizzlin’ Fun Fact

Leanne is an actress as well as a writer, and one of her most cherished performances was getting an opportunity to play Captain Hook in a production of Peter Pan. Thanks to her theatrical training, she also does accents and can cry on cue (but would prefer not to, thanks). She’s also a D&D nerd to her core.


Let’s get this out of the way; Leanne is not a fan of writing about herself. She much prefers writing about others! With a background in theater and dialogue writing, Leanne has a special talent for capturing an audience’s attention while being hyper-aware of a brand’s voice. Good copy is, to her, a complex potion made of dialogue, poetry, visual art, psychology, and computer science. Luckily, these are some of her favorite subjects!

In addition to her love of storytelling, Leanne adores problem-solving. It is that problem-solving drive that makes her copy functional as well as entertaining. Whether it’s writing copy for your website, social media pages, a blog post, an email campaign, or a neat little lead magnet, Leanne excels at creating valuable content that draws eyeballs.

Every brand is a character with a unique personality: my job is to capture that personality, communicate its message and make people want more! Knowing that something I’ve written is helping a client while providing value to the readers is definitely the most satisfying part of my day!”


  • Generative AI
  • Copywriting
  • Strategic Planning
  • Social Media
  • Graphic Design

Achievements & Awards

  • Certified AI Marketing Strategy & Execution Specialist
  • B.F.A. Theater 
  • Copywriting Mastery Certification
  • Marketing Mastery Certification
  • SEO Certified