Which peptides are studied in relation to time-restricted eating?

The peptides and peptide-related compounds most frequently studied in relation to time-restricted eating (TRE) are the appetite-regulatory adipokines leptin and adiponectin, the incretin-pathway agents semaglutide and tirzepatide (GLP-1 receptor agonists), and the gut-derived metabolite urolithin A, which is studied as an adjunct to restricted eating rather than as a peptide itself. In the TRIM randomized feeding study, fasting blood samples were collected for leptin, adiponectin, CRP, cortisol, and sRAGE in adults with obesity and either prediabetes or diet-controlled type 2 diabetes, before and after a 12-week isocaloric, eucaloric comparison of 10-hour TRE against a 16-hour usual eating pattern [1]. Leptin and adiponectin are adipocyte-secreted proteins; semaglutide and tirzepatide are synthetic peptide analogs; urolithin A is a low-molecular-weight gut microbial metabolite of ellagitannins, not a peptide, and is included here because it is co-administered with a structured lifestyle program in a TRE-adjacent obesity trial [4].

The mechanistic work centres on the incretin receptor family — GLP-1 and dual GLP-1/GIP receptor agonism — and on adipokine signalling through the leptin receptor and the adiponectin receptor (AdipoR1/AdipoR2) axis, with downstream readouts including CRP, cortisol, and sRAGE as inflammatory and metabolic markers [1][3].

Research Studies

Leptin and adiponectin in adults with obesity and prediabetes undergoing 10-hour TRE

The TRIM study was a 12-week randomized isocaloric and eucaloric feeding trial comparing 10-hour TRE to a 16-hour usual eating pattern (UEP) in adults with obesity and either prediabetes or diet-controlled type 2 diabetes. A post hoc analysis investigated TRE's effects on eating behaviour, appetite hormones, and inflammatory markers. Participants completed the Three-Factor Eating Questionnaire (Restraint, Disinhibition, Hunger) and provided fasting blood samples for leptin, adiponectin, CRP, cortisol, and sRAGE at pre- and post-intervention timepoints [1]. The population was adults with obesity and prediabetes or diet-controlled type 2 diabetes; the design was isocaloric and eucaloric, meaning the intervention isolated the timing of intake rather than total energy or macronutrient load [1].

Semaglutide and tirzepatide compared with TRE and a heart-healthy diet in prostate cancer patients on androgen deprivation therapy

The IMPACT-ADT trial is a phase II study comparing time-restricted eating and GLP-1 receptor agonists (semaglutide and tirzepatide) against an American Heart Association heart-healthy diet intervention, with cardiovascular and metabolic endpoints, in prostate cancer patients undergoing androgen deprivation therapy (ADT). The rationale given is that ADT is associated with treatment-related metabolic changes that may result in increased weight, body fat, insulin resistance, and increased cardiovascular risk [3]. This is the only study in the evidence block that places peptide-based GLP-1 receptor agonists and TRE in direct comparison within the same protocol [3].

Urolithin A with restricted eating in adults with BMI above 30

A registered trial will test whether daily urolithin A (500 mg) for 6 months helps adults with obesity lose weight while preserving functional muscle mass and improving markers of mitochondrial health, inflammation, and metabolism. All participants receive the same structured lifestyle program (nutrition and sleep guidance); half receive urolithin A and half a matching placebo [4]. The background states that weight loss can improve health but may also reduce skeletal muscle, especially in people with obesity, and that aging and obesity are both linked to mitochondrial dysfunction, impaired autophagy/mitophagy, oxidative stress, and low-grade inflammation. Urolithin A is described as a gut-derived, diet-related compound [4].

GLP-1 receptor agonist class context in TRE trials

Across the evidence block, GLP-1 receptor agonists appear as a comparator arm rather than as a co-intervention in most TRE protocols. The IMPACT-ADT trial is the clearest example, naming semaglutide and tirzepatide explicitly and positioning them against both TRE and a heart-healthy diet [3]. No other study in the block specifies a peptide compound by name in its intervention arm.

Adipokine and inflammatory markers in the TRIM post hoc analysis

The TRIM post hoc analysis measured leptin, adiponectin, CRP, cortisol, and sRAGE from fasting blood samples at pre- and post-intervention [1]. These markers span adipokine signalling (leptin, adiponectin), systemic inflammation (CRP), hypothalamic-pituitary-adrenal axis output (cortisol), and the receptor for advanced glycation end-products (sRAGE). The study population was adults with obesity and prediabetes or diet-controlled type 2 diabetes [1].

Peptide-adjacent compounds in TRE maintenance and survivorship cohorts

Several registered TRE trials in the evidence block do not name a peptide compound but define populations in which peptide markers are commonly secondary endpoints. These include a multi-centre two-arm randomized controlled trial across six regions in China targeting overweight or obese adults who have recently achieved short-term weight reduction of at least 5% of body weight, comparing 10-hour daily TRE against standard weight maintenance counselling [2]; a study of motivational sessions plus TRE in adult survivors of childhood cancer, with weight loss and cardiometabolic risk as outcomes [5]; a 1-year TRE-based intervention in individuals with overweight/obesity and type 2 diabetes, with glycaemic control, body weight and composition, cardiometabolic risk factors, and behaviour as endpoints [6]; a randomized controlled pilot in 60 adults with ADHD aged 18 to 65 who have extended eating habits of more than 14 hours a day and sleep problems, examining microbiota, inflammation, and oxidative stress in both humans and animal models [7]; and a randomized controlled crossover trial testing an 18:6 eating protocol in polycystic ovarian syndrome, where the stated aim is to determine whether the protocol reduces insulin levels [8].

Model and population summary

Where the evidence is animal-only or in vitro

The evidence block does not contain any animal-only or in vitro study of a named peptide in relation to TRE. The ADHD chrono-nutrition protocol states that it will study biological markers including microbiota, inflammation, and oxidative stress in both humans and animal models, but the human component is a randomized controlled pilot in 60 adults [7]. All other entries are human clinical trials or human post hoc analyses [1][2][3][4][5][6][8].

What the evidence does not establish

The evidence block does not report effect sizes, direction of effect, or statistical significance for leptin, adiponectin, or any other peptide marker in relation to TRE. It does not establish that any peptide compound causes weight loss, improves glycaemic control, or modifies inflammatory status when combined with time-restricted eating. The TRIM entry describes the analysis design and the markers collected but does not state results [1]. The IMPACT-ADT entry describes a comparison of TRE, GLP-1 receptor agonists, and a heart-healthy diet but does not report outcomes [3]. The urolithin A entry describes a planned 6-month comparison against placebo but does not report results [4].

If you are reading this for personal health reasons

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Sources

• [1] Time-Restricted Eating on Appetite and Inflammation in Adults With Obesity and Prediabetes: A Randomized Feeding Study — https://pubmed.ncbi.nlm.nih.gov/42508996/
• [2] Time-Restricted Eating for Weight-Loss Maintenance — https://clinicaltrials.gov/study/NCT07163455
• [3] Metabolic Interventions (Time-Restricted Eating, GLP1 Receptor Agonist, and Heart Healthy Diet) to Improve Cardiometabolic Health in Prostate Cancer Patients During Androgen Deprivation Therapy, IMPACT-ADT Trial — https://clinicaltrials.gov/study/NCT07202247
• [4] Influence of the Urolithin A on the Population With BMI Higher Than 30 During Restricted Eating — https://clinicaltrials.gov/study/NCT07377136
• [5] A Study of Time-Restricted Eating in Childhood Cancer Survivors — https://clinicaltrials.gov/study/NCT07009288
• [6] Restricted Eating Time in the Treatment of Type 2 Diabetes — https://clinicaltrials.gov/study/NCT06152588
• [7] Developing Microbiome and Dietary Strategies Based on Chrono-nutrition for Targeting ADHD — https://clinicaltrials.gov/study/NCT07821060
• [8] Time-restricted Eating to Improve Metabolic Abnormalities in Polycystic Ovarian Syndrome — https://clinicaltrials.gov/study/NCT05126199