Who are Function of Beauty?
Function of Beauty is a DTC beauty brand built on personalization. Launched in 2015 by 2 MIT grads and a cosmetic chemist, the idea was simple: why should everyone use the same shampoo when no one has the same hair? So they flipped the script. You take a quick quiz, share your hair or skin type and goals, and they whip up a custom formula made just for you—freshly mixed in their U.S. lab. Everything’s vegan, cruelty-free, and free from all the usual bad stuff like sulfates and parabens.
What started as a niche online brand quickly became a cult favorite. Today, Function of Beauty offers custom hair, body, and skincare through their site and retail partners like Target. But even with that retail growth, they’ve stayed true to their DTC roots—letting customers co-create products that actually work for them.
Hair raising open rate
Function of Beauty faced a familiar challenge: a growing group of lapsed customers who had gone dark on digital. Despite trying all the usual re-engagement tactics, this segment stayed unresponsive—making it clear that a new approach was needed to win them back.
Knowing digital wasn’t cutting it, the team started exploring other ways to reconnect. They saw how Paper Run had helped brands like Twillory, Sunday, and Create, so they decided to give direct mail a shot and test it as part of their marketing mix.
Split (Ends) Test: Mail vs. No Mail
To measure the true impact of adding Direct Mail to their marketing stack, the team at Function of Beauty decided to run an incrementality test.
Thanks to Paper Run’s integration with Klaviyo, they set up automated Direct Mail flows aimed at “unreachable” churned customers—people who had fallen off the radar and weren’t responding to emails or ads. Using Paper Run’s built-in A/B testing tools, they easily launched an incrementality test to see just how much Direct Mail could move the needle.
Test Group: Received beautifully personalized mailers.
Control Group: Didn’t get the mailers—just the usual email flows and retargeting ads.
Lift That Turns Heads
The results of the split test showed just how powerful Paper Run can be in helping brands like Function of Beauty boost retention and grow their customer base—profitably.
Conversion Uplift: A 260% increase in repeat purchases compared to the control group.
Incremental ROAS: A 3.6X lift in incremental return on ad spend—beating out many digital channels.
This automated flow now runs daily for Function of Beauty, steadily improving retention and driving incremental profit with zero extra effort from their team.
Senior CRM & Retention Manager, Function of Beauty
More CASE STUDIES
Read more about how the world's best DTC brands are converting customers who don't open their emails.
