The company
ThirdLove is a women's intimates brand, founded by Heidi Zak and Ra'el Cohen, best known for pioneering half-cup bra sizing; its bestselling T-shirt bra has sold more than 10 million units. The brand built its business direct-to-consumer and has since begun expanding into wholesale, with retail partners including Nordstrom and Kohl's.
Where they started
Per Klaviyo's account, ThirdLove's Senior Director of Growth and Retention, Leanne Chan, identified three compounding problems with the brand's prior setup: its email platform made basic personalization (showing or hiding content blocks for different customer segments) hard enough that it required developer time for changes that should have been simple; email and SMS ran on separate platforms, which meant a customer's behavior on one channel couldn't trigger or inform a message on the other; and the brand's own customer account pages were difficult to drive meaningful traffic toward, leaving a self-service opportunity on the table.
What they did
ThirdLove consolidated both email and SMS onto Klaviyo's B2C CRM, which unlocked a few specific changes rather than just "the same emails on a new platform":
- Dynamic, show/hide content blocks that ThirdLove's team could build without developer involvement.
- Cross-channel flows — a behavior on SMS could now trigger or suppress an email, and vice versa, using Klaviyo's channel-affinity logic to decide which channel a given customer responds to best.
- Integrations with Digioh (bra-fit quiz data) and Yotpo (loyalty), so quiz answers and loyalty status could both feed segmentation, not just purchase history.
- A Customer Hub — a self-service account experience for order status, loyalty points, and support, replacing the underused legacy account pages.
The numbers
Klaviyo's case study reports H1 2025 SMS ROI of 15x, more than $200,000 in revenue attributed to the Customer Hub with over 40,000 self-service interactions, and a loyalty point redemption rate that hit an all-time high of 30% in the 30 days before the case study was published. Email, SMS, and flow revenue all grew quarter-over-quarter in Q2 2025.
Source: Klaviyo's ThirdLove case study. Customer Hub: $200K+ attributed revenue, 40K+ self-service interactions.
Why this worked
The headline number (15x SMS ROI) is easy to over-credit to "SMS is just a great channel." What Klaviyo's account actually describes is more specific: the ROI jump came from SMS and email being able to inform each other's timing and content once they ran on the same platform, plus segmentation getting sharper by pulling in data (quiz answers, loyalty status) that used to live in disconnected tools. A channel that already worked in isolation got meaningfully better once it stopped operating in isolation.
What to take from this if you're earlier in this path
If your email and SMS run on different platforms today, the ROI you're likely leaving on the table isn't really about either channel individually — it's the flows that should exist between them (an SMS follow-up to an unopened email, an email suppressed because SMS already converted the customer) and can't, structurally, until they share data. Start with Email Marketing Fundamentals and SMS Marketing for Ecommerce to get each channel's own fundamentals right before consolidating.
FAQ
Is a 15x ROI figure typical for SMS, or is ThirdLove an outlier? Treat it as a strong result from a mature, already-large SMS list rather than a typical starting point — this site's own Email & SMS Flow Revenue Share benchmark page gives a more representative range across brands of different sizes and list maturity.