How Sigma Beauty Grew Flow Revenue 24% by Sending Fewer Emails

Direct answer: A retention program with high unsubscribe rates and deliverability problems isn't a volume problem — it's a quality problem. Sending more emails into a degraded list makes it worse. Sigma Beauty came to Sticky Digital in January 2024 wanting a partner who could think alongside them, not just execute. What that partnership produced was a counterintuitive intervention: a deliberate reduction in flow deliveries to fix the underlying list health, resulting in a 24% increase in total flow revenue and $25K in additional flow revenue. The emails that stopped sending were the ones that were actively working against the program.

What Sigma Beauty Was Looking For

Sigma Beauty is a professional makeup tools brand — the 3DHD Blender, precision brush collections, and a skincare line built around the same exacting standards as their tools. Founded by Simone Xavier, the brand has a reputation built on product quality and a loyal customer base that takes its application technique seriously. A blender with patented 3DHD edges and an air-tight hygiene seal isn't an impulse purchase — it's a considered buy from someone who cares about the result.

The brief going into the engagement reflected that sophistication. Sigma didn't need an agency to run their email program. They needed a partner who could think alongside them — someone who would bring a point of view, not just a campaign calendar. Simone X., CEO and Co-Founder, described what they found: "Working with the Sticky Digital team has been a genuinely positive experience."

The word "genuinely" is doing work in that sentence. Genuinely positive, from a founder, after a partnership that included deliberately reducing delivery volume — that's a grade earned by being right about something counterintuitive, explaining it clearly, and then being proven right by the numbers.

The Problem With Sending Too Much

High unsubscribe rates and unhealthy deliverability are symptoms, not root causes. They're signals that the program is reaching people who don't want to be reached — either because the segmentation logic is too broad, the send frequency is too high for the engagement level of the list, or both. Left unaddressed, these symptoms compound: every unsubscribe shrinks the list, every deliverability hit reduces inbox placement, and every email landing in spam is being counted as "delivered" while actively damaging sender reputation.

The temptation in this situation is to address it with content improvements — better subject lines, sharper creative, stronger offers. Sometimes that's the right move. But when the underlying issue is that the flows are reaching too many disengaged or mismatched contacts, creative improvements can only do so much. You can write the best email in the history of Sigma Beauty's program and it won't convert a subscriber who joined four years ago, hasn't opened in eighteen months, and is one more send away from hitting "unsubscribe" or marking it as spam.

The correct intervention is surgical: identify which contacts the flows are reaching who shouldn't be receiving them, tighten the entry criteria, adjust the frequency logic, and accept that a smaller, healthier audience will outperform a larger, degraded one. That's what Sticky recommended and what Sigma agreed to test.

What a 5% Decrease in Deliveries Looks Like in Practice

A 5% reduction in flow deliveries sounds small. In practice, it means that 5% of the contacts who were previously entering flow sequences — triggering welcome emails, post-purchase sequences, replenishment reminders, loyalty onboarding — were removed from those paths because they were the wrong contacts, at the wrong time, with the wrong engagement history to justify the send.

That 5% wasn't random. It was the segment of the flow audience that was most likely to unsubscribe, least likely to convert, and most capable of damaging deliverability for the remaining 95%. Removing them from the flow audience doesn't just stop the damage they were causing — it improves the signal for every metric the remaining audience generates. Open rates improve because the denominator is healthier. Click rates improve for the same reason. Deliverability improves because the program is no longer training ISPs to expect low engagement on Sigma's sending domain.

The 24% increase in total flow revenue on a 5% smaller delivery base is the clearest possible statement of what list health actually means for a program's economics. Revenue went up because quality went up. The math of fewer-but-better is not subtle here.

$25K in Additional Flow Revenue From a Healthier Program

The $25K in additional flow revenue is the concrete return on the list health investment. It's not theoretical. It's the revenue the program generated above what it had been generating before the intervention — with fewer emails sent.

For a brand like Sigma with a high-consideration product and a customer who repurchases on a meaningful timeline, the compounding effect of this matters. A loyalty program member who receives the right onboarding email at the right moment and converts to their second purchase is worth more than the $25K figure captures, because that second purchase is the beginning of a retention pattern, not a one-time transaction. The rewards program creative — "Welcome to Sigma Beauty Rewards," earn points across purchase, upload receipt, and subscribe to texts — is the kind of multi-channel engagement sequence that works when the underlying audience is healthy enough to receive it. It doesn't work when the list is so degraded that the email lands in spam or triggers an unsubscribe before the customer can read the offer.

What "Thinking Alongside" Actually Requires

Simone's brief — needing a partner who could think alongside them, not just execute — is a high bar. It means the agency has to be willing to recommend things the client might initially push back on, and be right enough about the reasoning that the pushback becomes buy-in.

Recommending a deliberate reduction in email volume to a brand that's looking for growth is one of those recommendations. The instinct on the client side is often the opposite: if the program isn't performing, send more. If open rates are low, try harder subject lines. If revenue is flat, run a promotion. These moves can work. They're also the moves an order-taking agency makes without questioning whether the underlying list health supports them.

A partner who thinks alongside a brand asks first: is the audience we're sending to the right audience for this message? Is the frequency we're running healthy for this list's engagement profile? Are the metrics we're optimizing for the right ones, or are we chasing volume at the expense of quality? These are harder questions to answer and harder recommendations to make. They're also the questions that produced a 24% flow revenue increase on a smaller delivery base for Sigma Beauty.

The Loyalty Layer and What It Signals

The Sigma Beauty Rewards onboarding creative is prominent in the results slide for a reason. A loyalty program is one of the highest-leverage retention mechanics available to a brand with Sigma's customer profile — professional-quality tools and skincare with a real repurchase pattern — but it only produces that leverage when the audience receiving the onboarding is qualified and engaged enough to act on it.

A loyalty welcome email landing in a disengaged contact's inbox doesn't just fail to convert. It consumes deliverability budget, contributes to the unsubscribe and spam signal, and represents a missed opportunity to build the relationship with a customer who might have been a genuine loyalty program participant if the email had reached them at a better moment, with better segmentation, on a healthier list.

The list health work Sticky did for Sigma isn't separate from the loyalty program — it's the prerequisite for it. A loyalty onboarding sequence that runs on a healthy, engaged audience converts. The same sequence on a degraded list doesn't. The order of operations matters: fix the list, then run the loyalty flow. Sigma's $25K in additional flow revenue reflects what happens when that sequence is followed correctly.

What an Ongoing Partnership Produces That a Project Can't

Sigma's engagement is listed as January 2024 to present — ongoing. That's a different relationship than a fixed-term engagement, and it produces a different kind of value.

List health isn't a one-time fix. Subscriber behavior changes, new contacts enter the list with varying engagement profiles, seasonal send patterns affect deliverability, and the segmentation logic that was right when it was built needs review as the program evolves. An ongoing partner reviews these things continuously — not as a project deliverable, but as standard operating practice.

A 24% flow revenue increase and $25K in additional revenue are the results of the first intervention. What an ongoing partnership compounds on top of that is the sustained discipline of keeping the list healthy, the flows relevant, and the sending patterns calibrated to what the audience will actually respond to. That compounding is what a partner relationship produces and a project-based engagement can't.

Frequently Asked Questions

Why would deliberately sending fewer emails increase revenue?

Because email revenue is a function of audience quality as much as volume. A disengaged subscriber who unsubscribes after receiving a flow email was never going to generate revenue — but they were generating unsubscribe signal and deliverability cost. Removing them from the flow audience improves the engagement metrics for the remaining audience, which improves deliverability, which improves inbox placement, which means more of the emails that do go out actually reach and convert active customers. The 24% flow revenue increase on a 5% smaller delivery base is the math of quality winning over volume.

How do you identify which flow contacts should be removed?

Through engagement history and behavioral segmentation. Contacts who haven't opened or clicked in a defined window, contacts who have repeatedly received a specific flow without converting, contacts whose entry criteria suggest they're a poor match for the sequence they've entered — all of these can be identified through Klaviyo's segmentation tools and used to build exclusion logic for flow entry conditions. The specific thresholds depend on the brand's list composition, send frequency, and the individual flow's conversion baseline.

What does an unhealthy deliverability signal look like in Klaviyo?

The clearest signals are increasing bounce rates, increasing spam complaint rates, and declining open rates that don't correspond to a change in creative quality or send timing. Deliverability problems that originate in list health tend to develop gradually — a single send with high spam complaints, followed by a slight inbox placement decline, followed by a gradual open rate erosion. By the time the numbers are obviously bad, the sender reputation damage has been accumulating for months. Weekly deliverability monitoring is the practice that catches these signals early.

How does loyalty program performance depend on list health?

Directly. A loyalty onboarding email that lands in a disengaged contact's inbox doesn't convert them into a loyalty program participant — it consumes deliverability budget and contributes to unsubscribe signal. Loyalty flows produce the best results when the audience receiving them is engaged, has recent purchase history, and is at a lifecycle stage where loyalty program participation is relevant. List health work creates the conditions for loyalty flows to perform. Without it, the loyalty investment underproduces regardless of how good the onboarding creative is.