Every supplement brand we’ve audited comes in convinced their email problem is creative. Wrong subject lines, tired templates, not enough discounts. It’s almost never that. When you pull a supplement brand’s Klaviyo account and look at what’s actually broken, the answer is nearly always structural: flows that don’t map to the reorder cycle, segments that treat a first-time buyer the same as someone on their eighth bottle, and replenishment timing based on guesswork instead of consumption data.
The case studies below are useful precisely because they’re specific. Nuun, The Collagen Co., Vital Nutritive, DY Nutrition, and Supplement Needs are real programs with public numbers attached, not composite examples built to make a point look tidier than it is. Read them the way you’d read a competitor’s playbook: not for the headline growth percentage, but for the mechanic underneath it that you can actually replicate in your own account.
Why supplement email economics work differently
Most ecommerce email benchmarks assume a purchase cycle measured in months or seasons. Supplements don’t work that way. A collagen powder, a pre-workout, a daily vitamin, these get consumed on a 30 to 60 day cycle, which means the customer is generating a predictable, recurring reason to hear from you again. That’s a structural advantage almost no other product category gets for free.
It also means the cost of getting retention wrong compounds faster. If a customer runs out of product and doesn’t hear from you at the right moment, they don’t wait around, they buy the next bottle from whoever shows up in their inbox or their Amazon “buy again” list. Retention Side’s own benchmark data on the category reflects this: winback flows that recover just 5 to 10 percent of lapsed supplement buyers each month represent meaningful incremental revenue, precisely because the repurchase window is so tight and so frequent.
This is also why flow architecture matters more in supplements than almost any other vertical. Klaviyo’s 2026 benchmark data across more than 183,000 brands shows flows generating roughly 41 percent of total email revenue from just 5.3 percent of total sends, with flow revenue per recipient running around 18 times higher than campaigns. In a category built on repeat consumption, that gap between automated and manual sending isn’t a nice-to-have efficiency stat. It’s the difference between a retention system and a newsletter.
Put differently, campaigns still matter, but the revenue engine of a mature email program is the automated layer that fires regardless of what’s on the campaign calendar.
What these case studies have in common
Before getting into each brand, it’s worth naming the pattern up front, because it repeats across every case study below almost word for word:
- Segmentation depth beat broad blasting every time revenue jumped meaningfully.
- SKU-level replenishment timing, not a generic 30-day timer, was the single most cited lever.
- Post-purchase flow coverage engineered the second purchase instead of hoping for it.
- List and deliverability hygiene underpinned every program that scaled sending without losing inbox placement.
None of these brands won by writing better subject lines. They won by rebuilding the underlying system. That distinction matters, because it’s the difference between a tactic you can copy for a week and a framework you can run for years.
Nuun: segmentation by product line drove an 820% jump in email revenue
Nuun makes hydration and vitamin tablets and had been on ExactTarget before making the move to Klaviyo. After the switch, email-channel revenue grew 820 percent year over year according to Klaviyo’s official case study, and email-driven site traffic rose more than 950 percent, and email came to represent roughly 40 percent of Nuun’s monthly revenue. Total company revenue grew 3x year over year over the same window.
The number that gets quoted is the 820 percent, but the driver behind it is less flashy and more instructive: Nuun segmented its list by product line rather than treating every subscriber as one undifferentiated audience. Endurance athletes buying electrolyte tablets for long runs got different messaging than customers buying the vitamin line for daily wellness, who got different messaging again from customers in a recovery-focused segment. Nuun also used timezone-based sending for its ambassador program, which alone lifted open rates by more than 10 percent.
The lesson here isn’t “segment your list,” which is advice every email vendor gives away for free. The lesson is that relevance architecture has to exist before volume does. Nuun didn’t grow revenue by sending more email. It grew revenue by making sure the right subset of its list received the message that actually applied to how they used the product.
The Collagen Co.: replenishment without forcing a subscription
The Collagen Co. sells premium collagen powders on Shopify Plus, and its Klaviyo case study reports 698 percent year-over-year total revenue growth, alongside more granular 2023 figures: campaign revenue up 67 percent year over year, flow revenue up 33 percent, and email subscriber count up 319 percent. Those component figures are separate confirmed metrics from the same year, not pieces that sum to the headline number, so don’t try to reconcile them into a single equation.
What matters more than any of those percentages is the mechanic The Collagen Co. built. Instead of pushing every customer into a locked subscription, the brand used Klaviyo’s predicted run-out data to trigger replenishment emails timed to when a customer was actually likely to be running low, with subscription offered as a convenience rather than a requirement. Back-in-stock alerts went out across both email and SMS to catch demand the moment inventory returned, and quiz data collected through Okendo fed personalization into the flow so messaging matched the customer’s original purchase reason.
This is the supplement category’s signature move: replenishment as an earned recommendation rather than a locked-in commitment. Customers who feel pushed into a subscription churn faster than customers who feel reminded at the right moment. The Collagen Co.’s numbers suggest the reminder-based approach scales better than the lock-in approach, at least when the underlying prediction data is accurate.
Vital Nutritive: the rebuild sequence that took email from 8.9% to 33% of revenue
Vital Nutritive is a Barcelona-based hair-loss and wellness supplement brand with a list of more than 40,000 subscribers. Starting an agency engagement in January 2023, the brand grew email revenue 368 percent in the first four months, with email’s share of total revenue climbing from 8.9 percent to 33 percent, per YOCTO’s published case study. Campaign revenue’s share of that email total went from 15 percent to 50 percent as sending scaled from a handful of campaigns per month to three per week, layered on top of tiered segmentation.
What makes Vital Nutritive worth studying isn’t the percentage, it’s the order of operations. The rebuild didn’t start with campaigns. It started with flows in the first 30 days, then added campaign cadence once the flow foundation was solid, then layered in SKU-based replenishment flows timed to send a subscription upsell a few days before a customer was projected to run out of their specific product. A Klaviyo-to-Yotpo integration handled loyalty enrollment on top of that structure.
This sequence mirrors the diagnostic order Retention Side runs on every new account: deliverability first, then list health, then flow coverage, then campaign strategy. Vital Nutritive didn’t jump straight to “send more campaigns,” because more campaigns sent through a broken flow foundation just accelerates unsubscribes and spam complaints. Fix the automated backbone first. Campaigns amplify a healthy system; they don’t fix a broken one.
DY Nutrition and Supplement Needs: retention outgrowing the store
Two UK sports nutrition brands illustrate the same pattern from different starting points. DY Nutrition, the Dorian Yates brand, reported 47 percent year-over-year Klaviyo-attributed revenue growth in eComOne’s case study, with email eventually responsible for 45.18 percent of total website revenue. Unsubscribe rate dropped 50.3 percent over the same period, even as overall online revenue grew 62.4 percent, meaning the email program grew faster than the store around it, not just alongside it. That growth happened despite intermittent stock availability, which the brand had to actively manage around in its messaging rather than treat as a side issue.
Supplement Needs, a UK evidence-based sports nutrition brand founded in 2016, ran a full Klaviyo overhaul that produced a 171 percent increase in email revenue year over year, a 117 percent increase in abandoned cart revenue, and a 95 percent increase in new subscribers.
The pattern connecting both brands is the real takeaway: email growing faster than the store itself is the clearest signal a retention system is actually working, as opposed to just riding the coattails of overall growth. When email’s share of revenue climbs while acquisition stays flat or grows more slowly, that’s retention doing the heavy lifting rather than new customer volume masking a flat or declining repeat-purchase engine.
The benchmark reality check
It’s worth grounding all of this against category-wide numbers before you go compare your own program to any single case study above. Across Klaviyo’s full benchmark cohort spanning all verticals, email typically represents around 27 percent of total store revenue. Third-party analysis built on top of Klaviyo’s data argues that high-repeat consumable categories like supplements can sustainably push that number to 30 to 45 percent, given how frequently the product needs to be repurchased. Treat that higher range as informed opinion rather than an official Klaviyo-published figure, but it lines up with what the case studies above actually show: Vital Nutritive landed at 33 percent, DY Nutrition at 45.18 percent.
Use this as a self-diagnostic, not a report card to feel good or bad about. If your supplement brand’s email revenue share sits meaningfully under 20 percent, the gap is very rarely a creative problem. It’s almost always flow coverage: no predicted replenishment logic, thin post-purchase sequencing, or a winback flow that either doesn’t exist or fires too late to catch a customer before they’ve already reordered somewhere else.
The before-and-after pattern behind those end-state numbers is consistent, too. When two programs that published both figures are lined up, one agency engagement with an unnamed collagen supplement brand took email’s share of total revenue from 20 to 30 percent, while Vital Nutritive climbed from 8.9 to 33 percent in four months.
What to copy and what to skip
Not everything in these case studies transfers cleanly to your brand, and treating a borrowed number as a target is a common way agencies and in-house teams waste a quarter chasing the wrong thing.
Transferable mechanics worth building regardless of your specific product:
- Replenishment flows timed to predicted run-out rather than a flat 30-day timer for every SKU
- Product-line or use-case segmentation, so a customer who bought for one reason doesn’t get messaging built for a different reason
- Reorder reminders framed as a convenience, not a forced subscription commitment
- Post-purchase sequencing built specifically to engineer the second purchase, since that’s the strongest predictor of long-term customer value
Non-transferable specifics to leave behind:
- Exact timing windows (Nuun’s timezone sends, Vital Nutritive’s “a few days before run-out” cadence) were tuned to those brands’ specific consumption data and audience behavior
- Headline growth percentages, since they reflect each brand’s starting baseline, not a universal ceiling or floor
- Specific offer structures and discount depths, which depend on your margin and category competitiveness, not on what worked for someone else’s collagen powder
One independent data point worth noting here: an 8-week, 50/50 A/B test on a Shopify supplement brand found that predicted run-out replenishment emails outperformed fixed 30-day timers by 27 percent in repeat-purchase revenue, with a 2.1x higher click-to-reorder rate. That’s a useful confirmation that the mechanic, not the specific brand story, is what’s doing the work.
Where this leaves your program
The honest read across every case study here is that none of these brands found a growth hack. They rebuilt the same four things in roughly the same order: deliverability, list quality, flow coverage, and campaign strategy, then let the supplement category’s short repurchase cycle do what it naturally does when the system underneath it is sound.
If you’re looking at your own email revenue share and it doesn’t resemble any of the numbers above, that gap is diagnosable. It usually traces back to a missing or poorly timed replenishment flow, segmentation that’s still treating your whole list as one audience, or deliverability issues quietly capping how much of your sending ever reaches an inbox in the first place. That’s the order we work through with every supplement and wellness brand we take on, and it’s the same order worth running on your own account before your next campaign calendar gets built.