Microdose Tirzepatide: New Study Reports 4.4- to 6.9-Pound Average Weight Loss by Day 59
Retrospective analysis of 60 adults on compounded tirzepatide, 1–2 mg weekly: 4.4 lb average among 57 at days 14–35,
Press Release Disclaimer: This is a press release distributed through the XPR Media network. It has not been independently verified by our newsroom.
ALPHARETTA, Ga., Sept. 21, 2026 (GLOBE NEWSWIRE) — A newly posted PlexusDx preprint documents average self-reported body-weight loss of 2.2%, or 4.4 pounds, among 57 adults with eligible measurements during days 14–35 of treatment, at a median of 21 days. Among 19 patients with measurements during days 36–59, the average loss was 3.6%, or 6.9 pounds. The 60-patient analysis evaluated compounded injectable tirzepatide initiated at 1 or 2 mg per week, below the usual 2.5 mg weekly starting dose.
The retrospective study, posted on medRxiv Sept. 17, has not been peer reviewed. It had no comparison group and cannot establish that treatment caused the observed weight changes.
The PlexusDx study page provides a plain-language summary, charts and study limitations.
Weight changes observed during low-dose treatment
The analysis incorporated 93 eligible follow-up measurements from 60 adults documented as newly initiated on GLP-1 treatment. Results from the Sept. 2 data freeze were:
- Days 14–35: 2.18% average body-weight loss, or 4.4 pounds, among 57 patients; median treatment exposure, 21 days.
- Days 36–59: 3.58% average loss, or 6.9 pounds, among 19 patients; median exposure, 48 days.
- Days 60–89: 6.10% average loss, or 12.2 pounds, among only eight patients; median exposure, 65.5 days. This small, selected subset warrants particular caution.
Patients could be included in multiple time windows. The later estimates do not represent all 60 patients, and no eligible observation reached 90 days. Measurements after escalation above 2 mg per week were excluded.
“A smaller dose still needs evidence. We observed early weight loss, but this study cannot establish that lower doses work as well as standard treatment or are safer. Those questions require prospective comparative research,” said Jayden Lee, PharmD, EMBA, medical director of PlexusDx and study co-author.
Limits of the evidence
Weights were self-reported, most treatment-start dates were estimated, and inclusion required documented follow-up, creating potential selection bias. Analysis decisions evolved during retrospective review. The study does not establish comparative safety, dose equivalence or long-term outcomes.
The formulation studied was compounded tirzepatide with vitamin B12, not an FDA-approved tirzepatide product. Compounded drugs are not FDA-approved; the FDA does not review them for safety, effectiveness, or quality before marketing. The preprint is not intended to and should not guide clinical practice or self-directed dose changes.
PlexusDx supplied internal resources and routine-care records; no external funding was received. Both authors hold leadership roles at PlexusDx, which operates the commercial program studied. These roles are disclosed as potential competing interests.
Read the full medRxiv preprint. De-identified data and analysis code can be provided upon reasonable request to the corresponding author.
About PlexusDx
PlexusDx is a precision-health company based in Alpharetta, Georgia. Its telehealth weight-management program supplied the routine-care records analyzed in this study.
A photo accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/dfcf7f07-449c-4555-a878-7edf4b67087c
Media contact: Jay Hastings, CEO, PlexusDx | info@plexusdx.com | 877-760-2333
