See how [Company] cut churn by 30%, free webinar inside
When you reveal a 30% reduction in churn, you ground your promise in data. Adding “Free Webinar Inside” clarifies the cost and channel.
Type: Case Study Webinar
Tone: Data‑driven, persuasive
How [Client] Achieved [Result]: Real Case Study Enclosed
Type:
Case Study, Follow-up, Marketing
Tone:
Direct, Professional, Trustworthy
I use this case study email subject line when I want to make a clear promise about what’s inside.
Use it when attaching a PDF or linking to a blog. Keep the result specific to avoid misunderstandings and include “Enclosed” to make it feel more tangible.
Case Study Email Example
Subject: How Acme Corp Achieved a 45% Reduction in Churn: Real Case Study Enclosed
Hi [Name],
I wanted to share a quick case study where Acme Corp cut churn by 45% in just three months using our retention toolkit.
Inside the attached PDF you’ll find step-by-step tactics, metrics, and a clear timeline.
I think you’ll find the strategies immediately actionable.
Feel free to reach out with any questions,
[Your Name]
Your Peer [Client] Increased [Metric] with [Solution]
I love this subject line because social proof is a powerful motivator.
It targets your reader by implying that a peer did it, too. Be sure to replace [Client] and [Solution] with the correct information.
This Subject Line Can Also Be:
- Your Peer [Client] Saw [Metric] Growth Fast
- How [Client] Leveraged [Solution] for [Metric] Gain
- [Solution] in Action: [Client]’s [Metric] Success
How [Client] boosted [Metric] by [%] in [Time]
Type: Results-Driven, B2B, SaaS
Tone: Clear, Curious, Achievable
I recommend this subject line to clients who value hard numbers. It includes three key elements: a recognizable client, a tangible metric (such as “conversions” or “ROI”), and a timeframe.
For instance, “How Shopify Scaled Support Capacity by 40% in 6 Months” immediately signals relevance to eCommerce brands.
When to Use It
It’s perfect for cold outreach or nurturing leads familiar with your product. Avoid using it if the metric isn’t impressive or verifiable.
Inside [Industry]’s win against [Pain Point]
Type: Storytelling, B2C, Education
Tone: Relatable, Empathetic, Narrative
This frames the case study as a battle story. Words like “win” and “against” add a touch of drama without exaggeration. For example, “slow refunds” or “patient no-shows.”
It works because it mirrors the reader’s daily struggles.
Note: Keep the pain point specific and avoid generic terms like “challenges.”
When to Use It
It’s ideal for re-engagement campaigns or industries where emotions drive decisions, such as healthcare and nonprofits. Skip it if the pain point isn’t universally hated.
[Client]’s secret to [Achievement] (Spoiler: It’s Simple)
Type: Curiosity, Marketing, SMB
Tone: Playful, Intriguing, Human
The “spoiler” hook evokes the feeling of gossip and taps into FOMO. It’s ideal for sharing surprising or counterintuitive results. For example, consider the headline, “Local bakery’s secret to 90% repeat customers.”
When to Use It
It’s great for newsletters or loyal audiences. Avoid using it in formal industries, such as law or banking.
Potential Pitfalls
Many of us hate “clickbait.” Counter this by providing immediate value in the first line of the email.
Can we collaborate? Guest post that drives 7k visits
You start by offering a partnership, then provide a concrete metric: 7,000 visits. This makes the promise feel measurable, not like hype.
Numbers in the subject lines help you push email open rates.
When to Use
I reserve this line for sites with high domain authority. Show a quick case study in the body; link to analytics screenshots.
Type
Partnership Outreach, SEO‑Focused
Tone
Data‑backed, ambitious, energizing
This Subject Line Can Also Be:
- Guest post idea: 7 k‑visit case study for you
- Proven topic that pulls 7 k readers
Real story: how [customer name] saved 40 hours with us
You tap human curiosity here. Readers love specifics, so “40 hours” feels concrete, not hype.
Social proof lifts open rates because 89% of people trust recommendations from people they know.
Schedule this line inside a weekly customer‑story drip, right after onboarding finishes, when fresh users still compare options.
Inside the email I suggest adding a:
- Three‑step timeline
- One hero quote
- A prominent “Try the shortcut” button.
Clear number, clear outcome, clear next move, and customers will appreciate that.
Type
Social Proof, Case Study
Tone
Inspiring, data‑driven, matter‑of‑fact
Example Email
Hi [first name],
Remember those late nights juggling reports?
Alex from FintechCo shaved two full workdays each month after switching to our template.
Tap to watch the two‑minute walk‑through.
Show me the workflow
Talk soon,
Customer Success Team
See why 1,203 users just rated us five stars
Big, round numbers inspire trust, but the word “just” indicates new information, which is better than stale praise.
Automated flows that feature social proof outperform bulk campaigns.
Use this subject line after a feature release so the new score feels earned.
Inside, embed a scrolling marquee of snippets, each limited to 120 characters for fast scanning.
A final CTA nudges readers to “Browse all reviews” which keeps compliance teams happy by avoiding cherry‑picking only glowing lines.
Type
Review Highlight, Community Proof
Tone
Excited, evidence‑based, upbeat
Before and after: watch revenue climb 32% for Sarah’s shop
Type
Success Snapshot, Storytelling
Tone
Narrative, motivating, friendly
Readers lean in when they spot a friendly name. Consumers (around 30%) trust reviews as much as personal recommendations from friends and family, so pairing a percentage with a relatable owner amplifies credibility.
Pair the subject line with a 30‑second GIF showing Sarah’s dashboard tick upward.
Beneath, keep the prose plain: what problem she faced, what action she tried, what result emerged.
A single “Replicate Sarah’s playbook” button to drive clicks.
