Direct-to-Consumer Telehealth Company

A Telehealth Brand's Open Rates Went From 13% to 73% and Held There for Seven Months

A 30x jump in send volume pushed a roughly 1-million-contact list into spam. An audit found the cause, and engagement-first sending brought it back.

Published October 19, 2026 by Truitt Dill

12.9% → 73.2%Broadcast open rate

0% → 100%Gmail inbox placement

0.53% → 0.05%Spam complaint rate

8 of 8Google sender requirements met

Client Snapshot

A direct-to-consumer telehealth company with roughly 1 million email contacts. Email is its main retention channel, and the marketing team sends from their email platform. They came to us in March 2026 after open rates fell by more than half in about six weeks and Gmail started filtering most of what they sent.

The Situation

Monthly send volume had run between about 38,000 and about 164,000 through the second half of 2025. It reached just over 1 million in January 2026 and nearly 4.9 million in February, nearly 30 times the old peak.

Google rate-limited a January 1 send. User-reported spam complaints averaged 0.53% against a 0.1% guideline and peaked at 4.0%. Account-wide open rates slid from 40-60% to about 20%. In February, broadcast sends to hundreds of thousands of recipients opened at 9% to 15%, and one send to about 700,000 recipients opened at 10.9%.

Our placement test showed 39.7% inbox placement overall and 0% at Gmail, Outlook, and Hotmail. Gmail and Microsoft consumer addresses made up 70% of the list, so 0% there covered most of the business. A flagged link-tracking domain triggered a Google "low reputation" warning on click. The unsubscribe flow was not one-click, marketing consent sat inside the Terms of Service, and the list carried at least 1,600 contacts at misspelled domains such as gmail.con and yahoo.con.

Authentication was clean. DMARC passed at 100%, and Google still rated the domain's reputation "High."

What We Did

We started by ruling out the usual suspects. SPF, DKIM, and DMARC all passed, and no blacklist listed the domain, so the problem was behavior. The volume spike lined up with every metric that broke, and the High domain reputation meant the damage could still be reversed.

Before the audit formally began, we told the team to cut volume and stop treating the full list as one audience. Sends would go by engagement tier, starting with contacts who had interacted in the last 14 days, and older tiers would come back only once open rates held above 40%. They acted on it right away. By late February, broadcast sends had dropped from as many as 700,000 recipients to about 150,000. On March 13, a send to about 84,000 engaged contacts opened at 74.1%, a week before the audit readout.

The audit then confirmed the cause and set out what had to change around it. We delivered a prioritized roadmap and implemented it:

A new link-tracking domain to replace the flagged one
True one-click unsubscribe
Explicit marketing consent at sign-up, separate from the Terms of Service
A reply-capable sender address in place of no-reply
Suppression rules for contacts inactive 120 days or more, hard bounces, role-based addresses, and misspelled domains
A move from DMARC quarantine to reject
A dedicated IP once reputation was repaired
Removal of unused DNS records for other sending platforms that left the domain open to spoofing

The Results

Reported open rate, 2026 year to date

Volume-weighted by delivered messages, by month

*Through Oct 18

Open rate is weighted by delivered volume from ESP broadcast campaign reports, January through October 2026 (October through the 18th). It excludes sends under 1,000 recipients, A/B test splits without a send date, tests, and in-progress sends. January is based on a partial export for that month. Open rates can be inflated by mail privacy features, so seed test placement is the primary measure. Sending also moved from full-audience sends in January and February to engaged segments from March onward, so the open rate reflects both placement and audience selection.

Broadcast open rates rose from 12.9% to 73.2%. February averaged 12.9% across 17 campaigns and 4.64 million delivered emails. From March 24 through October 18, 2026, the average was 73.2% across 102 campaigns and 4.68 million delivered emails.
Reach went up, not just the rate. September produced 624,000 opens, more than February's 599,000, while sending about one-sixth as much mail. Click rate rose from 0.30% in February to 1.37% across the recovery period.
The recovery held. Monthly averages ranged from 66.7% to 79.2% between April and October, and 81 of the 102 sends since March 24 opened at 70% or higher.
The comparison is stark at the send level. A February send to about 700,000 recipients opened at 10.9%. Recent sends to engaged segments of 27,000 to 72,000 recipients open at 70% to 82%.
Spam complaints dropped well below the threshold, though not in a straight line. Google Postmaster showed a 0.53% average and a 4.0% peak at the audit. In June and July, as older engagement tiers were tested back in, single days spiked as high as 2.06%, and those tiers were scaled back. Across 75 reporting days from August through October, the daily rate averaged 0.05%, and 70 of those days stayed under Google's 0.3% line.
Inbox placement reached 100% at every consumer mailbox provider tested, including Gmail, Outlook, and Yahoo, as of October 7, 2026, up from 0% at Gmail, Outlook, and Hotmail in the March audit.

0% to 100% inbox at Gmail and Outlook

Seed test results, March 2026 audit vs. October 7, 2026

March audit: 39.7% inbox placement across all providers tested. Gmail and Microsoft consumer addresses were 70% of the list.

Source: Formula Inbox seed tests

Google's Compliance status dashboard showed all eight sender requirements as Compliant on October 16, 2026, including one-click unsubscribe and user-reported spam rate, with user signals rated positive.

In Their Words

"When your list passes the million-mark in B2C health, a deliverability drop to 15% is a commercial crisis. The Formula Inbox team didn't just diagnose the bleeding, they completely rebuilt our domain health and sender architecture. Months later, our open rates still consistently sit above 70%. That’s not an incremental optimization; it completely transformed our retention revenue. If you have an enterprise list and deliverability is slipping, Formula Inbox is the only call you need to make."
Marketing executive, direct-to-consumer telehealth company

Results vary by sender. Formula Inbox does not guarantee inbox placement or any specific result.