Cold email outreach Guide

40+ Powerful Email Subject Lines, Essential to Successful Email outreach

Published , Updated 6 mn
Profile picture for Hugo Lebras

Hugo Lebras

Expert Growth B2B

Hugo is head of growth at Octolis, a new generation CDP. With solid experience on all B2B growth drivers, Hugo regularly shares best practices and hot takes on Salesdorado

Before you start diving into each and every detail of your cold emails, your emails will need to make it to your targets’ eyes. Subject lines are one of those things we all tend to overlook, but make no mistake, they’re probably the most important part of your email outreach campaigns.

The sole purpose of the email subject line is to entice the recipient to open the email. It should attract attention, arouse interest and make the recipient want to know more. There are a few techniques for creating effective email subject lines: formulate a question, create a state of urgency, play on emotion, integrate elements of personalisation, etc.

Before we dive in

Here’s a simple brutal fact: no trick in the world can offset irrelevance. All of these examples are meant as optimisation tricks and tips, and they do not replace, in any way, solid research and targeting. If you get this sort of right, your baseline should be around 70% open rates. Anywhere short of that, none of the tips in this post will help. You’ll need to go back to the drawing board, and think long and hard about who you’re reaching out to, why, and what’s in it for them.

We’ll cover all of these techniques by showing you over 40 successful examples of email subject lines. The article is divided into three sections, with each section corresponding to a particular type of email:

  • first contact emails
  • follow-up emails
  • and finally breakup emails

A final note: no matter how relevant, optimised and researched your emails are, do not forget to follow-up. Setting up automated follow-ups is a great way to ensure you cover at least 2 or 3 touch-points. Provided your outreach is relevant, there are millions of reasons for your prospects not to open your email. Cover your bases with a few follow-ups. Ideally, add value each time, but a simple 2 liner can get you an incremental 20% open rate easily.

15+ examples of first contact email subject lines

When you’re reaching out to someone for the first time, you really have to work on the subject line of the email, find a striking subject line that your prospect will not be able to ignore. Again, relevance beats any hack here. The best way to get your email open is for your recipient to feel like he knows you.

For a first contact email, questions are usually fairly effective. Here are some examples:

  • #1 Are you the right person to discuss XYZ?
  • #2 Are you in the market for XYZ?
    Note that you should only send this if you know for a fact that they are…
  • #3 Could you point me in the right direction?

According to a report by Adestra, personalised subject lines (in any way, by mentioning the prospect’s name for example) increase the chances of your email being opened by 22.2%.

  • #4 Martin, any advice?
  • #5 Martin, could you help me?
  • #6 Eric (M.) thought we should talk
  • #7 Eric thought I should reach out
  • #8 Trying to get to the person in charge of XYZ at CompanyName
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Referrals offer a huge advantage when reaching out for the first time. If you have a contact in common with the prospect, mentioning them in the subject line will add credibility to your message and significantly increase the chances of your email being opened.

Further readingFind out how to find the right email address for your contacts to ensure you get an open every time!

Try to highlight the concrete benefits of your offer, your product or your services in the subject line. Here are a few ideas:

  • #9 How [Competitor] earned [Amount] with [Product]
  • #10 How [Competitor] achieved [Challenge] with [Product]
  • #11 Bug report.
  • Again, this has to be an actual bug report or nothing good will come out of it…

  • #12 A more effective way to [Benefit from your product].

Another effective technique is to pique your prospect’s curiosity by not telling them what’s in the email but making them want to know. Here are two examples of objects that exploit this technique very well:

  • #13 Do not open this email.
    This is a classic example of reverse psychology. Telling your prospect not to do something will cause them to do the exact opposite.
  • #14 You are not alone.
    This rather original email subject line works on several levels. It is very intriguing, and therefore hard to ignore. In addition, it allows you to highlight a pain point in your email, which is an excellent approach for a first contact. For example, you can tell the story of some of your customers in the email, explaining how they managed to overcome obstacles thanks to your product.

You can also include a time variable in the subject line of your email to create a sense of urgency. This is a great technique to get your prospects to click on the email right away, without waiting:

  • #15 Martin, are you free on [Date close to date of email]?
  • #16 15 minutes on [Date] ?
  • #17 10 x [desired result] in 10 minutes?

Note that asking directly for time to your prospects only works if they have made some sort of commitment beforehand. These work great for prospects that signed up for a webinar or signed up to a SaaS product, but they’ll dramatically fail if you’re just reaching out to people who have never heard of you or your company.

Pro tip

Tired of Excel files? Reliable and easy to use CRM software is the cornerstone to effective outreach. Check out our selection of the best free CRM software

10+ examples of follow-up email subject lines

The subject lines examples in this section can be applied to emails sent after the prospect has responded to an initial email or after an initial sales meeting. Follow-up emails can be sent to prospects who need a little push to move up the conversion funnel or to those you haven’t heard from for some time.

There are several possible approaches. The first possibility is to send a friendly reminder. In the best case, your prospect will be happy to hear from you and will come back to you. The subject line of the first reminder email should be light and friendly. It should not put pressure on the prospect, the last thing you want is to make them feel guilty for not replying earlier.

  • #18 Next steps?
  • #19 Summary
  • #20 Following up
  • #21 Thank you

Another option is to link the subject line of the email directly to a topic you discussed with the prospect in the last meeting (either on the phone or face-to-face).

For example, if your prospect asked you a question and you were not able to answer it accurately at the time, you can use the follow-up email to answer the question in depth. More generally, you can take advantage of follow-up emails to deliver more value to your prospect:

  • #22 I was wrong!
  • #23 Here is the article we discussed at our last meeting

If you are using the phone to contact your prospects and the messages you leave on the answering machine are not being answered, you may want to consider sending a follow-up email. Here are some ideas for email subject lines:

  • #24 Sorry I missed you today
  • #25 Is everything ok?
  • #26 Are we still on track?
  • #27 Availabilities
Pro tip

Tired of Excel files? A good CRM software allows you to take your prospecting to the next level. Discover our selection of the best free CRM software

10+ examples of breakup email objects

Haven’t heard from your prospect in a while? Followed up several times, without success?

At some point, after 3 or 4 reminders, it’s basically useless to persist. Worse, it affects your pipeline speed to keep leads in the pipe too long. It’s time to move on to another approach: send them a breakup email, and call it “Closed Lost” for now.

A breakup email is not quite the same as a final reminder email. The aim is merely to let them know that you won’t be following up, and any next step would have to come from them. You’re effectively putting the ball in their court, and letting them know. That’s it.

Don’t ask what happened, they probably won’t want to tell you if they haven’t. Don’t blame them. Don’t take anything personally. Things happen, companies move fast, priorities change, and people have personal lives too. All you’re trying to do here is let them know the door’s open in case this comes back into their priorities.

Here are some examples of subject lines for these emails. First of all, you can play on the emotion:

  • #29 Looks like this isn’t a priority anymore?
  • #30 Did things change?
  • #31 I’ll be available if you need me

Including thank-you notes in a follow-up email or breakup email helps to arouse the prospect’s curiosity. Thank you formulas are rarely found in prospecting emails. Putting them in an email distinguishes you from other messages received by your prospect. If the prospect does not know why you are thanking them, they will be encouraged to click on the email to find out.

  • #32 Thanks for the chat Martin
  • #33 Loved our chat, hope you did too!
  • #34 Guessing you went another way, thanks for chatting with me
Further reading

Check out our complete guide to the art of setting up effective sales processes.

Another approach is to take open another communication channel, for example by offering to connect on Linkedin or Twitter. You’re basically acknowledging that this isn’t the right time or topic for conversation, but you’re also saying you enjoyed the conversations and would like to stay in touch. It’s a great way of defusing the situation, and create a more human and hopefully durable relationship.

  • #35 Let’s stay in touch
  • #36 Sent you a request on Linkedin
  • #37 Hope it’s not something I did!

Another approach: saying goodbye in the subject line. FOMO is a powerful tool. :

  • #38 Closing this thread for now
  • #39 Marking this read
  • #40 A final note

I hope that these different examples of email subject lines and approaches will help you to improve the open rate of your cold emails. If you still have low open rates, consider checking your email lists and using spam-testing tools to make sure deliverability is not the problem!

About the author

Profile picture for Hugo Lebras

Hugo Lebras

Hugo is head of growth at Octolis, a new generation CDP. With solid experience on all B2B growth drivers, Hugo regularly shares best practices and hot takes on Salesdorado