9 B2B Subject Line Strategies That Actually Work

The average business professional today sends and receives 116 business emails every single day. Email marketing NEEDS to be strategic if it wants to stand out from the noise – so I have compiled a few simple B2B subject line strategies for you to get those emails opened.

According to Chadwick Martin Bailey, 64% of the time people open emails because of the subject line. What you decide to use here could be the deciding factor in whether or not your email gets opened, and indeed, what type of response you will receive.

There are a lot of articles about subject lines out there so instead of giving you a few tips and tricks of the trade, I have compiled a series of tried and tested strategies I have used over the years, and explained a little of the scientific theory behind why they work.

Now, without further ado, 9 scientifically-backed pearls of wisdom to help your B2B email campaigns get the open rate they deserve:

1. Keep Your Subject Lines Short

B2B Subject Line Strategies - Yoda of subject lines

Human beings lack patience. Though the Microsoft Goldfish Study showing the human attention span to be less than a goldfish’s has been widely criticized, studies continue to show that due to the way we consume information in an era of new technology, the way the mind absorbs information has dramatically changed. With the world wide web at our fingertips, we are less likely to ‘deep read’ and more likely, according the University of London, to ‘power browse’ – skipping from one source of information to another. To adapt to this marketers have to write shorter and sharper, facilitating speed reading.

Total Send found in their AB tests that subject lines that were less than 5 words long beat subject lines longer than 8 words long 65% of the time. This makes complete sense when you consider the increasing use of mobile. 66% of all emails are opened on mobile devices which have much smaller screens. This means that subject lines longer than 50 characters (4-7 words) are cut short.

This doesn’t just go for the subject line. MailChimp found in their study of 200 million emails that emails that were a total of 28-39 characters generated the highest click rates – that is 50 words or less.

The Key Learnings:

  • Keep your subject lines under 8 lines long.
  • Think about being direct and precise in your copy – try your message in 50 words or less.
  • Test for yourself whether shorter copy is working for your services or products. There is no one size fits all email marketing strategy. Think about your audience and what they value.

2. Be Honest: Don’t Make Promises You Can’t Keep

B2B Subject Line Strategies - Honest Subject Lines

Human beings are suspicious creatures. We judge whether anyone we meet is ‘trustworthy’ in a tenth of a second or less. Because the average business professional is now exposed to  4,000 – 10,000 messages a day, the natural reaction to receiving anything expressly selling a product or service is distrust. According to research done by Adobe, 53% of prospects feel that marketing messages are always ‘a bunch of B.S’.

Not only are people wary of sales emails, they are wary of emails altogether. According to Verizon’s 2017 Data Breach Investigations Report, two-thirds of all malware businesses receive is installed via email attachments. This adds an extra level of scrutiny and needs to be considered when you select your B2B subject line strategy.

Cohn&Wolfe study shows that for the modern consumer the most valued characteristic in a brand is honesty in communicating products and services. Consumers distrust larger corporations and capitalist ventures – just 3% of American, British, Italian, Swedish, Spanish, and French consumers believe “big businesses are very honest and transparent.” In Germany, the number is as low as 1%. With a growing distrust of information in a post-truth era, B2B marketers must work twice as hard to earn credibility with their prospects.

The Key Learnings: 

  • Do not over-promise in your subject line. You only have one chance to make a ‘trustworthy’ first impression – it is more important you focus on your prospect’s pain points than exaggerating your services or products.
  • Avoid salesy language. This will make you seem more ‘corporate’ than ‘human’. People want to buy from people, specifically people that they trust.
  • Design the body of your message to be clean-cut and professional. Sloppy design or typos make you look unprofessional, and may even lead someone to believe you are impersonating your company to infiltrate theirs.

3. Tailor Your Subject Line To Each Recipient

B2B Subject Line Strategies - Beyonce

Imagine you are at a cocktail party and many people are talking to you at once. There are so many people talking that their voices are indistinguishable and all you hear is noise. However, if someone says your name, or something important to you, you are suddenly able to focus in. And that is something you can leverage in your B2B subject line strategies…

The Cocktail Party phenomenon demonstrates selective attention. There is a structure within our brains, the reticular activating system (RAS), that is responsible for orientation and attention – i.e. who you listen to at that crowded cocktail party. When presented with many options or distractions we naturally orientate towards information or ideas that we are invested in. Our brain is biologically designed to filter out what doesn’t interest us or what doesn’t benefit us.

Let’s apply this to email marketing. You need to reach out through the noise in your prospect’s inbox with something that will interest them, and motivate them to focus in. A report by Silverpop has found that 50% of recipients unsubscribe because the emails they are being sent are not relevant to them, and they don’t have any interest.

So you have to keep your email relevant to your prospect. Simple enough, right? Wrong. The DMA reports that 42% of marketers have admitted only some of the emails they send are relevant, and 10% have said that their emails aren’t relevant at all. You could even be losing relevancy by accident if you haven’t thought out your ideal buyer profiles or aren’t expressly operating with a customer-focus. ALWAYS know your audience.

Three key rules for this:

  1. Create a prospect profile to better understand who you are selling to.
  2. Create a prospect map to better understand where you should be selling.
  3. Segment your contacts and lists to reflect what you have learnt from 1 and 2. Tailor your messaging to suit your contact and your method of reaching out.

3. Use Ego To Your Advantage – We All Have One!

B2B Subject Line Strategies - Kardashian

People prefer talking about themselves than listening to others – that is why you always lead with their problems NOT your product. If you are in sales or marketing this is nothing new.

However, this is not just sales jargon. The Harvard University Social Cognitive and Affective Neuroscience Lab found that self-disclosure – a.k.a. talking about yourself and your problems – stimulates the same areas of the brain as sex, cocaine and good food. Talking about yourself activates a reward system which suggests that self-disclosure, more than any other stimuli tested, may be inherently pleasurable. We are motivated to talk about ourselves more than any other topic area.

Use this to your advantage in your B2B subject line strategies. Ask people personal questions about themselves and their businesses. Write a subject line that encourages them to respond and clearly signals your interest in what they have to say. People are more likely to open an email that allows them to self-disclose.

Here are a few examples:

  • “Feeling [insert emotion]? Let me help” – show that you understand your prospect’s emotional state and they will believe more in your ability to help them.
  • “Your annual goal” – centre your subject around your prospect and what they want to achieve, rather than what you are selling.
  • “Ever Had This Problem? Tell me about it”– show an interest in your prospect’s problems and they will be more inclined to open a dialogue with you.

4. Personalise Your Subject Line

B2B Subject Line Strategies - Pesonalisation

Personalisation is the latest email marketing craze. A report from Adestra cites that if you personalise your subject line there is a 22.2% higher chance of your prospect opening your email. But does science back this up?

The concept of implicit egoism states that because human beings tend to have positive associations about themselves, they naturally prefer things that are connected to themselves in some way.  SUNYAB conducted a series of studies measuring how implicit egoism could affect life decisions like where you live and what career you end up in. They found that people are disproportionately likely to live in places that resemble their own first or last names – so Louis is likely to live in St. Louis. They also found that people choose careers which resemble their names –  people named Dennis or Denise are overrepresented among dentists.

So how can we apply implicit egoism to our subject line? The answer is simple. Use the prospect’s name. Knowing someone’s name establishes an immediate connection with them, a connection that in social terms is incredibly powerful. As principle 3 in Dale Carnegie’s How to Win Friends and Influence People states, “Remember that a man’s name is to him the sweetest and most important sound in the English language.”

Some things you could try:

  • Add your prospect’s name into your subject line – either as part of the offer or as part of a question you may be asking.
  • Mention things specific and personal to your prospect in the subject line – like where they work, or their specific role.
  • Tailor your subject line to reflect what interests your prospect – using your prospect profile and prospect map to inform your copy.

5. Don’t Use Salesy Language (Yes It Is Possible)

B2B Subject Line Strategies - Bargains and Deals

Business professionals receive an overwhelming amount of messaging, and because sales messaging can be used as a vehicle for cyber criminals, your prospects distrust emails, particularly sales emails. You need to use language that doesn’t just sell your product but also paints you as reputable and credible. This isn’t just a B2B subject line strategy, this is B2B copywriting basics.

The other reason not to use salesy language is technological – spam filters. Using words like “free” or “open now” can trigger your recipient’s filter, and your beautifully crafted subject line will end up in the depths of their spam folder – never to be seen again. Adestra found that the word “free” lowers email open rates.

The Key Learnings:

  • Check whether the copy you are using, particularly in your subject line, contains any words that would trigger a spam filter.
  • Hubspot and Automational both provide in-depth lists, although Googling a list specific to your industry could be more helpful.
  • You can use tools such as ISnotSPAM to check your copy once written.

6. Try Referrals In Your Subject Lines


One of the biggest decision-factors over the modern consumer’s buying process, particularly if they are millennial or Gen X, is what other people think of the product. The Social Times reports that 92% of consumers trust recommendations from others, even people they don’t know, over branded content. 70% say that online reviews are their second-most-trusted source, and almost half of U.S. readers consult blogs regularly to keep up with trends and ideas.

So why does the influencer strategy work? Social Proof or Social Influence refers to the way human beings observe the behavior of others and use this to inform their actions in specific social situations. Social Proof is why companies purchase ghost followers for their social media accounts, why brands are paying YouTubers for product placement and why brands are now incorporating user-generated content. People trust other people.

Referrals also trigger social proof. According to NoMoreColdCalling.com, referred prospects have an enormous 50% close rate.  If someone you know thinks you’d be interested or has referred something on to you, the proposition is more likely to seem a reputable solution. As referral sales expert Bill Cates puts it, new prospects “borrow trust” from the referral source, turning a cold email into a ‘warm’ introduction.

Referral grants the sender automatic credibility. It leverages an existing connection within the copy of the subject line, creating familiarity and putting the prospect at ease. A name will also stand out from the marketing buzzwords and salesy subject lines.

Here are some examples:

  • “I found you through [referral name]” – LeadGenius found that this line earned them an incredible 86.6% open rate for B2B sales, and it can easily work for you too.
  • “[referral name] recommended I get in touch” – this plays on the referral ‘trust’ effect and communicates clearly that you are reputable and credible.
  • “[referral name] from X company told me to talk to you” – being specific about both who is referring you and where they work gives the prospect a clear idea where you can help – particularly if they are from similar industries and have similar pain points.
  • “[referral name]” – this surprisingly works. Just a name, particularly the name of someone they know, piques the prospect’s curiosity and stands out in the inbox.

7. Let Them Know What You Are Bringing To The Table

B2B Subject Line Strategies - Gatsby

One B2B subject line strategy that helps both your appearance as credible and trustworthy, and helps with standing out in your prospect’s inbox, is to state clearly and concisely what you can achieve for your prospect. Remember to keep this centred on their pain points – your business is solving their problem.

“10x [prospect’s company]’s traction in 10 minutes” gained Salesfolk 16 new B2B customers because it states such an impressive set of figures in a short, engaging way. They appear credible, they state their value early on, and the potential for the prospect is clear right there in the subject line. Can you summarise your service and its benefits into one key sentence?

Here are some examples of other ways to immediately communicate value:

  • “How [a competitor] gains [high-level benefit]” – tailored to your prospect’s interest (their competitor) and immediately indicating the value of the content of the email.
  • “Idea for [business you are contacting]” – tailored to the specifics of your prospect’s business and indicating that contents is strongly in their interest immediately.
  • “A better way to [insert your service here]” – demonstrates an understanding of the prospect’s business and creates paints you as an authority worth reading more from.

8. Use Your Subject Line To Build Up Suspense


Curiosity is a well-known motivator of human behaviour – although exactly how it influences how we behave has been the subject of decades of debate. Here is how you channel two of the better known and more recent theories of curiosity into your B2B subject line strategies.

Curiosity Drive

One theory behind why human beings are driven by curiosity is that we are afraid of uncertainty. The absence of knowledge or understanding makes us feel anxious and uncomfortable. Relieving uncertainty is associated with reward. Because uncertainty induces negative feelings and relieving uncertainty induces positive feelings, humans find satisfying their curiosity rewarding and will actively seek to learn new things.

Here are a couple examples:

  • “Quick question” – this gives nothing away to your prospect so will stimulate that need to fill an information gap.
  • “Have you heard?” – this creates the sense that there is something important that your prospect doesn’t know, which will motivate them to click-through and open the email.

Information Gap

Recent research points to the absence of information as the main stimulus of curiosity. Human beings are motivated to fill gaps in their own knowledge, and the absence of information can, therefore, have a larger pull over a prospect than supplying them with enough information to click.

Here are a couple examples:

  • [no subject line] – the absence of a subject line has had surprisingly positive results. Hubspot’s  analysis of 6.4 million emails showed that messages with a blank subject line were opened 8% more often than those with subject lines.
  • “Amazing list of awesome — one more time!”– MarketingProfs found this subject line had a surprisingly high open rate given there is no mention of what the list is of.

9. Always Test Everything

Email Testing

So this strategy is a little different because it is an absolute NECESSITY. You need to test everything, and keep a sharp eye on what is working and what isn’t throughout your campaign process. This is how you determine which B2B subject line strategies work for which campaigns and which segments.

As Parry Malm from Econsultancy.com observes, “There are limitless possible emotional combinations of language available. Knowing which works best for your audience is impossible without testing. The opportunity is to quantify emotion … then optimize based on the results … then profit from better subject lines.”

There is no one-size fits all strategy for email marketing – we know this for a fact because we work with over 100 companies, each needing a different approach.

Here at Growthonics we focus our optimisation around two key tactics:

  • A/B testing – subject lines but also introductions, copy, formulas, messaging, primary offerings and sign-offs.
  • Monitoring responses – our account managers monitor both negative and postitive responses to help inform what strategy and messaging will be used in future campaigns. Because we built highly targeted lists to our client’s specifications, this can provide very valuable insight into target markets and target audiences.

If you want to talk to either myself or the team, get in contact and we will respond as soon as possible to help you get the most out of your outbound strategy.

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