Journal September 26, 2026 5 min read

Which peptides are studied in relation to insulin sensitivity?

A research-supply overview of peptides and related compounds investigated for insulin sensitivity, including spexin, galanin, SS-31, and DPP-4-related agents, with notes on model systems and evidence limits.

peptides-pro Editorial

In the research literature, the peptides most frequently studied in relation to insulin sensitivity include spexin and galanin, two neuropeptides involved in glucose homeostasis and energy metabolism [3]. Other compounds examined in this context include the mitochondria-targeted peptide SS-31 (elamipretide) [6], the dipeptidyl peptidase-4 (DPP-4) inhibitor vildagliptin [1], and nutritional agents such as sulforaphane [5] and hesperetin [9]. These substances are investigated across diverse models, from meta-analyses of human circulating levels to preclinical studies in aged mice.

The work centres on pathways regulating glucose uptake, insulin signalling, and metabolic homeostasis, with spexin and galanin specifically implicated in glucose homeostasis and insulin sensitivity [3].

Research Studies

Spexin and galanin in type 2 diabetes mellitus

A systematic review and meta-analysis synthesised evidence on circulating spexin and galanin concentrations in patients with type 2 diabetes mellitus (T2DM) compared to non-diabetic controls [3]. The analysis included observational studies reporting these neuropeptide levels in adults, with random-effects meta-analyses calculating pooled standardised mean differences [3]. The findings support the involvement of these neuropeptides in glucose homeostasis and insulin sensitivity, though the meta-analysis itself does not establish causality [3].

SS-31 (elamipretide) in aged female mice with MASLD

In a preclinical study, aged female C57BL/6 mice (12–14 months) were fed a high-fat, high-fructose diet for 16 weeks to induce metabolic dysfunction-associated steatotic liver disease (MASLD) [6]. Mice were randomised to control diet, MASLD, MASLD + MitoQ (25 mg/kg/day), or MASLD + SS-31 [6]. The study compared the mitochondria-targeted agents MitoQ and SS-31 for their effects on mitochondrial function, oxidative stress, apoptosis, and inflammation [6]. This evidence is animal-only and does not directly translate to human insulin sensitivity outcomes.

Vildagliptin and DPP-4 inhibition in polycystic ovary syndrome

Vildagliptin, a DPP-4 inhibitor, enhances endogenous incretin activity and may improve insulin sensitivity and glucose homeostasis [1]. A clinical trial is evaluating vildagliptin versus metformin in patients with polycystic ovary syndrome (PCOS), a condition where insulin resistance plays a central role in pathophysiology [1]. The trial investigates whether DPP-4 inhibition influences body weight, androgen excess, inflammation, and other metabolic parameters [1]. This work is in human subjects with PCOS, but results are not yet available.

Sulforaphane in obesity-related metabolic dysfunction

A narrative review evaluated sulforaphane, a bioactive isothiocyanate derived from broccoli and other cruciferous vegetables, for its antioxidant, anti-inflammatory, and metabolic regulatory properties [5]. The review critically assesses preclinical evidence and clinical perspectives in the context of obesity, adipose tissue dysfunction, insulin resistance, chronic low-grade inflammation, oxidative stress, and mitochondrial dysfunction [5]. The evidence includes mechanistic insights and preclinical data, with clinical perspectives noted but not yet definitive.

Hesperetin and gut microbial metabolism in aging mice

Dietary flavonoids often require microbial metabolism to generate bioactive metabolites that influence host physiology [9]. Hesperidin, a citrus flavanone glycoside, exhibits limited intestinal absorption and depends on gut microbial biotransformation to yield its active aglycone, hesperetin [9]. A probiotic Bifidobacterium pseudocatenulatum converts hesperidin to bioactive hesperetin and improves metabolic dysfunction in aging mice [9]. This evidence is animal-only and focuses on a specific microbial conversion pathway.

MitoQ and SS-31 comparison in aged female mice

In the same MASLD study described above, MitoQ and SS-31 were compared for their effects on mitochondrial function, oxidative stress, apoptosis, and inflammation in aged, nutritionally stressed mice [6]. The study design included four groups: control diet, MASLD, MASLD + MitoQ (25 mg/kg/day), and MASLD + SS-31 [6]. This head-to-head comparison provides preclinical data on mitochondria-targeted agents but remains animal-only.

Avocado consumption and brain insulin sensitivity in pre-diabetic individuals

A randomised crossover intervention study is assessing the effect of 12-week daily avocado consumption on cerebral blood flow and markers of cardio- and vascular health in pre-diabetic individuals with overweight or obesity [2]. The secondary objective includes assessing brain insulin sensitivity after intranasal insulin delivery, vascular function, markers of metabolic health, cognition, and psychological well-being [2]. A total of 34 men and women aged 40–75 years will participate [2]. This study is in humans but does not involve a peptide compound.

Estrogen and exercise training effects on glycemic control

Previous research has found that males and females respond differently to exercise training, particularly with respect to improvements in blood sugar control and immune system health [7]. Insulin resistance, which can lead to type 2 diabetes, affects millions of Canadians, and people with insulin resistance often have higher inflammation [7]. Exercise is known to improve insulin resistance and reduce inflammation, but females seem to benefit less from exercise compared to men [7]. Investigators believe this difference might be due to estrogen, a hormone that helps regulate blood sugar and reduce inflammation [7]. This study is in humans and focuses on exercise and estrogen, not a peptide.

Sleep-related Alzheimer's disease vulnerability and muscle-metabolic factors

A review advances a sleep-muscle-brain framework in which sarcopenia, sarcopenic obesity, and insulin resistance are conceptualised as modifiable muscle-metabolic conditions that may bias sleep continuity and shape the biological impact of sleep disruption [8]. Sleep disruption is a hallmark of aging and a plausible driver of Alzheimer's disease vulnerability, with reduced slow-wave sleep, increased fragmentation, and circadian instability potentially facilitating amyloid-β accumulation, tau propagation, neuroinflammation, oxidative stress, and impaired glymphatic clearance [8]. This review integrates insulin resistance into models of brain aging but does not study a specific peptide.

Estimated glucose disposal rate and endometrial cancer

A cross-sectional study from NHANES 1999–2018 evaluated whether the estimated glucose disposal rate (eGDR), a non-invasive insulin resistance metric, is associated with self-reported endometrial cancer [4]. The analytical sample consisted of 31,666 female respondents, including 248 endometrial cancer cases and 31,418 cancer-free comparators [4]. The eGDR was significantly lower in the endometrial cancer group (6.84 ± 2.76) than in the control group (7.51 ± 2.66) (P = 0.004) [4]. This study is observational and does not investigate a peptide intervention.

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