How We Checked the Data: Why 274 Candidate Records Became 60 Patients

Last updated: September 17, 2026

Written by: Jay Hastings, CEO of PlexusDx, and Jayden Lee, PharmD, EMBA, PlexusDx Medical Director

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Director, with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on Peptides & GLP-1. Browse all Peptides & GLP-1 education

Small studies earn trust by showing their work. This article shows ours. It walks through how the PlexusDx microdose tirzepatide study went from 274 candidate records to 60 patients, step by step, and how weights were chosen for analysis. Microdosing is not a medical term. In the PlexusDx study it meant a total weekly dose of 1 or 2 mg of injectable tirzepatide, below the usual 2.5 mg starting dose. The medication was compounded injectable tirzepatide with vitamin B12 at a total weekly dose of 1 to 2 mg.

From 274 to 220: was this really a new start?

We began with 274 adult candidate cases from the care program. Fifty-three were removed because the record showed prior GLP-1 exposure, a transfer from another program, a restart after a break, or an uncertain new-start status. The study was about people new to these medicines, so anyone who might not be new was removed rather than guessed at. One more record was removed because its baseline weight was unusable. That left 220 documented new starts with acceptable baselines.

From 220 to 127: was there a follow-up we could trust?

A start with no follow-up weight tells you nothing about change. Of the 220, 127 had at least one follow-up weight that passed audit. The rest did not, and they were not counted. Nothing was estimated for them.

From 127 to 73: did they meet the BMI rule?

The study asked about adults with a starting BMI of 27 kg/m² or higher. Seventy-three of the 127 met that rule.

From 73 to 60: did they have a qualifying observation?

Thirteen more left here. One patient had no treatment start date that could be established. Twelve had no observation that met the study’s three rules together: at least 14 days of adjudicated exposure, continuous treatment, and a weekly total of 2 mg or less. In detail: 10 had no follow-up reaching 14 days of exposure, 1 had a documented interruption of two weeks or more, and 1 had an otherwise eligible observation only after moving above 2 mg a week. That left 60 patients in the final analytic cohort.

From 93 weights to 84 window records

Those 60 patients contributed 93 eligible follow-up weights. The study sorted them into windows by days since the first dose: 14–35, 36–59, and 60–89. Eligible weights by window were 63, 21, and 9. When a patient had more than one weight in the same window, the study kept the latest one for the main tables. That gave 84 patient-window records: 57, 19, and 8 patients. The 9 extra same-window weights were not thrown away. They stayed in the statistical model that used all 93 observations. No weight reached 90 days, so there is no 90-day result.

What was never done

No missing weight was filled in by arithmetic. No patient was assumed to have kept losing. No comparison group was borrowed from a trial. Weights were self-reported at routine check-ins, and the study says so. Side-effect answers came from those same check-ins, matched for 58 of 60 patients; the 2 unmatched were treated as unknown, not as symptom-free.

How the rules were stress-tested

The authors re-ran the numbers three ways: using each patient’s first eligible weight instead of the latest; assuming treatment actually began three days after the recorded start; and assuming it began seven days after. Each version changes which weights land in which window and who stays eligible, so each gives slightly different numbers. The point was to see whether the rules drove the picture. These checks do not prove the results are free of dropout effects or confounding. They only show what happens when the timing rules move. The numbers themselves are on the study page and in results at 3, 7 and 9 weeks.

Why show all this

Because a reader deserves to know that 214 records were set aside, and why. Because “60 patients” means something different when you know how they were chosen. And because the next step, a prospective study with a comparison group and measured weights, will need these same rules written down in advance. To our knowledge (as of September 2026), the first published patient cohort reporting outcomes for injectable tirzepatide started at 1 to 2 mg a week.

About the PlexusDx study

A retrospective, single-organization observational study of adults documented as new to GLP-1 medicines with BMI ≥27 kg/m²; no comparison group; self-reported weights; not a clinical trial; preprint not yet peer reviewed. The records came from the commercial care program that PlexusDx operates. Care was delivered by an independent network of U.S.-licensed clinicians through a state-licensed telehealth platform. The medication was compounded injectable tirzepatide with vitamin B12 at a total weekly dose of 1 to 2 mg, prepared by state-licensed compounding pharmacies operating in FDA-registered facilities. The study was written by Jay Hastings (PlexusDx CEO) and Jayden Lee, PharmD, EMBA (PlexusDx Medical Director). See the PlexusDx microdose tirzepatide study (60 patients, 2026).

The authors’ conclusion, in their words: “These hypothesis-generating observations support prospective comparative study, not conclusions about causality, equivalent dosing, or long-term safety.” The full preprint is on medRxiv: Weight Loss With Microdose Tirzepatide: Real-World Outcomes in Patients Initiating Treatment Below 2.5 mg Weekly (doi:10.64898/2026.09.15.26363172; posted September 17, 2026; CC BY 4.0). It has not yet been peer reviewed.

Where PlexusDx fits

PlexusDx offers compounded tirzepatide through its Weight Management Protocols, including the entry-tier Microdose GLP-1 Protocol. You fill out a short intake. A licensed clinician reviews it and decides what, if anything, fits you. The study described here looked back at records. It is not a promise of any result.

This article is educational. PlexusDx offers compounded tirzepatide through its Weight Management Protocols. The GLP-1 & Peptide Pathways Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol. Compounded tirzepatide is not an FDA-approved drug product. It is prepared by state-licensed compounding pharmacies under federal compounding rules and is not the same as Zepbound® or Mounjaro®. Zepbound® and Mounjaro® are registered trademarks of Eli Lilly and Company. PlexusDx is not affiliated with or endorsed by Eli Lilly and Company.

Frequently Asked Questions

Why did 274 candidate records become 60 patients?

Fifty-three were removed for prior GLP-1 exposure, transfer, restart, or uncertain new-start status, and 1 for an unusable baseline, leaving 220. Of those, 127 had audited follow-up, 73 had BMI 27 or higher, and 60 had a qualifying observation under the timing, continuous-exposure and 2 mg/week rules.

Why did 93 weights become 84 records?

Sixty patients had 93 eligible follow-up weights. When one patient had more than one weight in the same window, the main tables kept the latest, giving 84 patient-window records: 57, 19 and 8. The 9 extra same-window weights stayed in the model that used all 93 observations.

Were any missing weights estimated?

No. Nothing was imputed or calculated to fill a gap. If a patient had no qualifying weight in a window, they simply do not appear in that window. That is why the later windows have fewer patients: 57 in the first, then 19, then 8 in the last.

Why is there no 90-day result?

Because no eligible observation reached 90 days. The study only reports what the records contained. The latest window is 60–89 days, with 8 patients and a median exposure of 65.5 days. Anything beyond that would be a guess, and the study does not guess.

What are the sensitivity analyses?

Re-runs of the analysis under different rules: first eligible weight instead of latest, and start dates shifted by three and seven days. They test whether the timing rules drive the results. They do not prove the findings are robust to dropout or confounding, and the authors say so plainly.

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Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.