Effect of short-term tirzepatide treatment on mean platelet volume in patients with obesity: a retrospective controlled study

In adults with obesity, two months of tirzepatide treatment was associated with a significant drop in mean platelet volume (MPV) and in body mass index compared with untreated controls. The authors describe the findings as hypothesis-generating rather than proof of a direct platelet-modulating effect.

Journal article — Retrospective controlled study. Population: Adults with obesity whose data were obtained from electronic medical records. Sample size: 60 adults. Follow-up: 2 months. Interventions: Tirzepatide.

Baseline BMI and MPV were comparable between groups (BMI 40.22 ± 4.10 vs. 39.86 ± 3.49 kg/m², p = 0.713; MPV 10.65 ± 0.87 vs. 10.18 ± 1.30 fL, p = 0.105). In the tirzepatide group, BMI fell from 40.22 ± 4.10 to 36.30 ± 3.90 kg/m² (mean change -3.92 kg/m², 95% CI -5.93 to -1.91; p < 0.001) and MPV fell from 10.65 ± 0.87 to 9.72 ± 1.17 fL (mean change -0.94 fL, 95% CI -1.44 to -0.44; p < 0.001). The between-group difference in MPV change was -1.35 fL (95% CI -2.22 to -0.48; p = 0.003). After adjustment for baseline BMI, baseline MPV, age, and sex, tirzepatide treatment remained independently associated with greater MPV reduction (beta -1.13, 95% CI -1.97 to -0.29; p = 0.009).

For researchers studying tirzepatide, this paper provides early, hypothesis-generating evidence that short-term treatment is associated with a lower mean platelet volume, a marker linked to platelet activation and inflammatory burden, in people with obesity. It does not establish a direct platelet-modulating effect, because inflammatory and platelet-function biomarkers were not measured and the design was observational and short-term. The findings do not support clinical or dosing recommendations.

Key findings

After two months of tirzepatide, MPV fell from 10.65 ± 0.87 to 9.72 ± 1.17 fL (mean change -0.94 fL, 95% CI -1.44 to -0.44; p < 0.001).
The between-group difference in MPV change was -1.35 fL (95% CI -2.22 to -0.48; p = 0.003), in favor of the tirzepatide group.
In adjusted regression, tirzepatide treatment remained independently associated with greater MPV reduction (beta -1.13, 95% CI -1.97 to -0.29; p = 0.009).
BMI in the tirzepatide group decreased from 40.22 ± 4.10 to 36.30 ± 3.90 kg/m² (mean change -3.92 kg/m², 95% CI -5.93 to -1.91; p < 0.001).
Baseline BMI and MPV were comparable between the tirzepatide and control groups (BMI p = 0.713; MPV p = 0.105).

Limitations

Retrospective design (stated by the authors)
Short two-month follow-up (stated by the authors)
No direct inflammatory or platelet-function biomarkers were measured (stated by the authors)
As an observational non-randomised design, residual confounding cannot be excluded and causality should not be inferred

The record

Journal: BMC endocrine disorders 26(1): 210
Published: 2026-07-16
PMID: 42464179 — DOI: 10.1186/s12902-026-02422-8
MeSH terms: Humans, Obesity, Body Mass Index, Case-Control Studies, Retrospective Studies, Follow-Up Studies, Adult, Middle Aged, Female, Male, Mean Platelet Volume, Tirzepatide
Author countries: Turkey

Peptide profiles: Tirzepatide.

All indexed evidence: Tirzepatide trials & papers.