B2B Email Subject Lines:Which Words Work and Which Don’t

B2B Email Subject Lines:Which Words Work and Which Don’t

As B2B companies, we want people to open the emails we send out in our B2B email marketing campaigns. More than that we want people to click on those emails and participate in our surveys, engage with our landing pages, explore our B2B websites, and purchase our products and services. The problem is that there are a lot of things that affect whether people open our emails or not: the time of day, the weather, and, yes, the subject line.

While we can’t control the weather, we can control what we put in the subject line. This is why the email marketing company Adestra researched more than 300 keywords and how they affected the open, click, and unsubscribe rates of over 125,000 email campaigns across four different industries. Doing so they were able to determine which words resulted in  higher open and click rates and which words caused more unsubscribes.

 B2B email

Which Words Work

The overall top performing keywords are words like:

  • Thank You
  • Thanks
  • Bulletin
  • Monthly
  • Golden
  • iPhone
  • Breaking

Thank You and Thanks are usually used in automated transactional messages. Normally when people purchase something online, they expect to be emailed a receipt, so it makes sense that these words would have phenomenal open rates.

Which Words Don’t

The worst overall performing keywords all warn against the dangers of dull and boring content. The worst performing keywords are words like:

  • Journal
  • Forecast
  • Training
  • Whitepaper
  • Learn
  • Intelligence
  • Report

Content is the lifeblood of any inbound marketing campaign, but that content needs to be engaging, relative, and useful. Truth is you may have put a lot of work into your B2B emails, but if your subject lines sound boring, your contacts won’t see those emails. If contacts suspect that an email is not worth their time, it’ll end up in the junk folder.

B2B Subject Lines

In this study, Adestra focused on four different industries:

  • Retail/B2C
  • Conferences/Events
  • Media/Publishing
  • B2B/Professional Services/Financial

Since we are a B2B inbound marketing agency, we will be focusing on the results for the final industry. If you are interested in findings related to the other fields then follow this link and download Adestra’s awesome whitepaper.

A B2B inbound marketing campaign can be a lot like dating. You’re fighting for contact’s attention while trying to nurture them into a long term relationship. You also want to be sure that you look more intelligent than your competitor. For this reason, the email can be considered the love letter of the B2B company. It takes time to nurture a lead, but if they get too many emails that they deem junk, they’ll unsubscribe. Once they unsubscribe: that’s it! They’re gone! This is why it’s so important not to treat the subject line as a last minute chore and take a little extra time to think about the words we use.

For higher open and click rates, the keyword news is always safe, but do not touch with a nine foot poll the word whitepaper which had an open rate of -208% and a click rate of -402%. Also stay away from :

  • Alert
  • Download
  • Forecast
  • Report

To help reduce the number of unsubscribes use words like:

  • Update
  • Bulletin
  • Industry
  • Interview
  • LinkedIn

Avoid the words:

  • Asset
  • Discount
  • Ipad


Now that you know the right and wrong words to use in your emails, how do you test these in your own email campaigns? Start with a look back at past campaigns. Do you have specific emails that have a higher open and/or click rate than others? Was there a specific email that triggered more unsubscribes? Can you find a reason in your headline or content?

After you’ve analyzed your past emails, choose one or two high performing words from the report. Reimagine your next email subject line with one of those words. From here you can test in a couple of ways. Split your list into two segments. Use the same email, but change the subject line so half of your list receives one subject and the other half receives the other subject line. You can also send the same email to all your contacts and change the keyword you use in next month’s email to compare two emails of different months.

We ran similar with one our clients and saw significantly higher opens when using the suggested keywords. We’d love to hear about your results or questions. Just leave it in the comments.