How a Single Underline Lifted Response by 38 Percent

The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing · Jun 17, 2026 · 8m · transcript

In this episode of The Copywriting Podcast, Lucas and Luna explore a surprising direct mail test: why underlining a single word in a headline lifted response by 38 percent. They break down the psychology behind emphasis in copy, how the brain processes underlined text differently, and how to apply this tiny but powerful technique to emails, landing pages, and even social media posts. Plus, they share a real-world example from a charity fundraising letter that doubled donations with just one underline. If you write anything persuasive, this episode will change how you think about formatting…