Peptide research roundup: 2 November 2026

This is the third edition of our weekly roundup of new peptide research. It covers papers indexed between 26 October and 2 November 2026 on the compounds in our catalogue, with what each study measured, in what model, and where it stops. Last week's edition is here.

It is a summary of published research, not medical advice and not a suggestion to use any compound on people or animals.

Tirzepatide: two animal studies and two records studies

Four new papers this week, two in animals and two drawn from health records.

• Diet timing and exercise in obese female mice (The Journal of Physiology, 30 October 2026). Macêdo and colleagues made female Swiss mice obese over 10 weeks, then gave them tirzepatide, time-restricted feeding (a 12-hour feeding window), stair-climbing resistance training, or combinations, for 8 weeks. Tirzepatide alone reduced weight gain. Adding time-restricted feeding and resistance training made weight fall faster, bringing body weight close to that of control mice, with less fat mass and smaller fat cells. Tirzepatide with time-restricted feeding improved glucose tolerance, and all the interventions reduced fat in the liver. This is a mouse study, and the authors note that how tirzepatide works in females had been unclear.
• A pulmonary hypertension model (Cells, 19 October 2026, indexed this week). Zhan and colleagues report that in a preclinical model of pulmonary arterial hypertension, tirzepatide was associated with better echocardiographic measures of the load on the lung vessels and less remodelling of the small lung arteries. In smooth muscle cells from those arteries, it reduced lactate build-up and a related histone mark (H4K12la), which the authors link to lower activity of the Jun gene through the AMPK and SIRT1 pathway. The authors describe it as a working model with preliminary translational implications.
• Gallbladder and pancreas events in health records (Journal of Clinical Medicine, 16 October 2026, indexed this week). Ghusn and colleagues used the TriNetX records network to compare adults with obesity and type 2 diabetes over one year, with 242,876 people in each matched tirzepatide and semaglutide group. Semaglutide use was associated with more gallstones (hazard ratio 1.11) and more gallbladder inflammation (hazard ratio 1.22) than tirzepatide use, while pancreatitis, bile duct infection and gallbladder removal did not differ significantly. GLP-1 receptor agonists as a group were associated with fewer of these events than DPP-4 inhibitors.
• Weight in insurance records (Diabetes, Obesity and Metabolism, 28 October 2026). Chinthammit and colleagues used US insurance claims data to follow adults without diabetes who kept filling tirzepatide prescriptions for 12 months and had weights recorded before and after. Mean weight fell by 19.3% in 230 people who had not used a GLP-1 receptor agonist before and by 13.1% in 123 people who had.

Both records studies are observational: they show associations, not cause and effect. The insurance study only counts people who stayed on treatment for a full year and had weights on file, so the figures do not describe everyone prescribed it.

Background: What is tirzepatide? and Retatrutide vs tirzepatide

MOTS-c: a pregnancy liver disorder model

In Cell Communication and Signaling (2026, indexed this week), Li and colleagues studied intrahepatic cholestasis of pregnancy, a liver disorder of pregnancy linked to problems in the placenta's blood vessels. They report that MOTS-c levels were lower in maternal blood and placental tissue from patients with the condition. In a mouse model, MOTS-c was associated with more blood vessel growth in the placenta, less death of its vessel-lining cells, and higher birth weight and newborn survival. In human umbilical vein cells, the authors found that MOTS-c binds a protein called BACH1 and speeds up its breakdown, which they link to more NAD+ being carried into mitochondria. Raising BACH1 in the cells removed the effect. The functional work is in mice and cells.

Background: What is MOTS-c?

NAD+: ageing hearts and immune memory

Two studies in mice look at what happens when NAD+ levels change.

• Ageing hearts (Cardiovascular Research, 30 October 2026). Huang and colleagues found lower NAD+ in the hearts of aged male mice, along with more senescent (aged, non-dividing) heart muscle cells, stiffer filling of the heart and more scarring. Two months of the NAD+ precursors nicotinamide riboside (NR) or dihydronicotinamide riboside (NRH) reduced senescence markers, improved how the heart filled and reduced thickening and scarring, which the authors trace to the SIRT1 and SIRT6 enzymes. Aged female mice also showed stiffer filling, but their heart NAD+ had not fallen and they did not respond to either precursor. The authors say this difference between the sexes needs to be taken into account in future work.
• Immune memory (Science Immunology, 30 October 2026). Jin and colleagues report that trained immunity, a form of memory in innate immune cells, raises NAD+ inside the cell nucleus. There it binds and blocks an enzyme called KDM5A, keeping inflammatory genes ready to respond. Blocking NAD+ production weakened this memory and its anti-tumour activity in mice, and the NAD+ precursor NMN restored it in mice lacking the enzyme NAMPT and in aged mice.

Background: NAD+ research

Nothing new this week

We found no new primary studies this week on retatrutide, BPC-157, TB-500 or thymosin β4, GHK-Cu, KPV, tesamorelin, Semax, Selank, ipamorelin, CJC-1295 or IGF-1 LR3. Retatrutide and GHK-Cu appeared only in review articles.

Compounds in this roundup

Certificates of analysis for each batch are on each product page once they are on file, and in the certificate library.

• Tirzepatide: the GIP and GLP-1 receptor dual agonist.
• MOTS-c, 10 mg: the 16-residue peptide encoded in the 12S rRNA gene.
• NAD+, 500 mg: nicotinamide adenine dinucleotide, the coenzyme found in every living cell.

Sources

• Macêdo A.P.A. et al. Combined time-restricted feeding and resistance training enhance tirzepatide-induced improvements in adiposity and whole-body insulin sensitivity in female mice. The Journal of Physiology, 2026
• Zhan S. et al. Tirzepatide Attenuates Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension: Association with the SIRT1/H4K12la/c-Jun Axis. Cells, 2026
• Ghusn W. et al. Biliary and Pancreatic Safety of Incretin-Based Therapies in Obesity and Type 2 Diabetes: A Propensity-Matched Real-World Comparison of Tirzepatide, Semaglutide, and DPP-4 Inhibitors. Journal of Clinical Medicine, 2026
• Chinthammit C. et al. Tirzepatide Use Resulted in Clinically Meaningful Weight Reduction in Individuals With Obesity or Overweight: 12-Month Real-World Results. Diabetes, Obesity and Metabolism, 2026
• Li S. et al. MOTS-c attenuates placental vascular endothelial cell apoptosis in intrahepatic cholestasis of pregnancy by inhibiting K33-linked deubiquitination of BACH1. Cell Communication and Signaling, 2026
• Huang Q. et al. NAD+ replenishment reduces cardiomyocyte senescence and improves diastolic function in the aged male heart. Cardiovascular Research, 2026
• Jin H. et al. Nuclear NAD+ promotes innate immune memory by inhibiting KDM5A-dependent histone demethylation. Science Immunology, 2026

For laboratory research use only. Nothing in this article is medical advice or a suggestion to use any compound on people or animals.