Journal September 25, 2026 5 min read

How does insulin sensitivity work?

Insulin sensitivity is the efficiency with which cells respond to insulin. This page outlines the mechanisms, research models, and clinical populations in which it has been studied.

peptides-pro Editorial

Insulin sensitivity: definition and scope

Insulin sensitivity refers to the responsiveness of target tissues—primarily skeletal muscle, liver, and adipose tissue—to insulin signalling. It is not a single molecule but a physiological state, quantified in research by metrics such as the estimated glucose disposal rate (eGDR) or by hyperinsulinaemic-euglycaemic clamp studies. The term is often used interchangeably with insulin action, though sensitivity specifically denotes the concentration of insulin required to produce a half-maximal effect. No single sequence, formula, or molecular weight applies, as insulin sensitivity is an emergent property of multiple pathways.

The work centres on the insulin receptor tyrosine kinase family and its downstream phosphatidylinositol 3-kinase (PI3K)/Akt signalling cascade, which mediates glucose uptake and metabolic regulation.

Research Studies

Vildagliptin and insulin sensitivity in polycystic ovary syndrome

In polycystic ovary syndrome (PCOS), insulin resistance is a central pathophysiological feature. Hyperinsulinaemia can enhance ovarian androgen production and reduce hepatic sex hormone-binding globulin synthesis, aggravating hyperandrogenism and reproductive abnormalities. Vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, enhances endogenous incretin activity and may improve insulin sensitivity and glucose homeostasis. A clinical trial is comparing vildagliptin versus metformin in patients with PCOS, with emerging evidence suggesting that DPP-4 inhibition may also influence body weight, androgen excess, and inflammation [1].

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. The secondary objective includes brain insulin sensitivity after intranasal insulin delivery, vascular function, and metabolic health markers. The study plans to enrol 34 men and women aged 40–75 years [2].

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). Spexin and galanin are neuropeptides involved in glucose homeostasis, insulin sensitivity, appetite, and energy metabolism. The meta-analysis included observational studies reporting circulating levels in adults with T2DM and non-diabetic controls, calculating pooled standardised mean differences [3].

Estimated glucose disposal rate and endometrial cancer

A cross-sectional study from NHANES 1999–2018 evaluated whether eGDR—a non-invasive insulin resistance metric—is associated with self-reported endometrial cancer. The analytical sample consisted of 31,666 female respondents, including 248 endometrial cancer cases. The eGDR was significantly lower in the endometrial cancer group (6.84 ± 2.76) than in controls (7.51 ± 2.66; P = 0.004) after propensity score matching [4].

Sulforaphane and insulin resistance in obesity

A narrative review evaluated sulforaphane, a bioactive isothiocyanate derived primarily from broccoli and other cruciferous vegetables, in obesity and obesity-related metabolic dysfunction. The review focused on mechanistic insights, preclinical evidence, and clinical perspectives, noting that obesity is characterised by adipose tissue dysfunction, insulin resistance, chronic low-grade inflammation, oxidative stress, and mitochondrial dysfunction [5].

Mitochondria-targeted agents in MASLD

A study in aged female C57BL/6 mice (12–14 months) compared MitoQ and SS-31 (elamipretide) for effects on mitochondrial function, oxidative stress, apoptosis, and inflammation in metabolic dysfunction-associated steatotic liver disease (MASLD). Mice were fed a high-fat, high-fructose diet for 16 weeks to induce MASLD and randomised into four groups, including MASLD + MitoQ (25 mg/kg/day). This evidence is animal-only [6].

Estrogen and exercise training effects on glycaemic control

Previous research has found that males and females respond differently to exercise training, particularly regarding improvements in blood sugar control and immune system health. Females appear to benefit less from exercise compared to men, and investigators believe this difference might be due to estrogen, which helps regulate blood sugar and reduce inflammation. A clinical trial is investigating whether estrogen blunts the effects of exercise training on glycaemic control in people with insulin resistance [7].

Sleep, muscle metabolism, and Alzheimer's disease vulnerability

A review advanced 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. Sleep disruption is a hallmark of aging and a plausible driver of Alzheimer's disease vulnerability, with reduced slow-wave sleep and increased fragmentation potentially facilitating amyloid-β accumulation and neuroinflammation [8].

Autophagy in hypothalamic neurons and obesity

Obesity is increasingly recognised as a disorder involving impaired central endocrine regulation, in which hypothalamic nutrient sensing, leptin responsiveness, and intracellular quality control are closely intertwined. Within the arcuate nucleus, autophagy exerts divergent metabolic effects in the two principal appetite-regulating neuronal populations [9].

Insulin sensitivity in polyendocrine metabolic ovarian syndrome

A cross-sectional study evaluated bone mineral density, body composition, sex hormone levels, and insulin sensitivity in women with polyendocrine metabolic ovarian syndrome (PMOS) compared with women without the syndrome. The study included 51 women with PMOS [10].

Senescent cells and age-related metabolic dysfunction

Senescent cells, which are normally cleared by the immune system but accumulate with age, contribute to multiple disorders including metabolic dysfunction and impaired fitness. Blocking programmed cell death ligand 2 (PD-L2) prevented senescent cell accumulation and age-related dysfunction in a non-cancerous, age-related context [11].

Proinsulin processing and glucose-lowering in type 2 diabetes

In type 2 diabetes, glucose-lowering is typically achieved by enhancing the capacity of pancreatic beta-cells to compensate for ambient insulin resistance. Impaired processing of proinsulin, reflected by an elevated ratio of fasting serum proinsulin to C-peptide (PI:C), is a marker of beta-cell stress. Glucose-lowering may be mediated by improved proinsulin processing without better beta-cell compensation [12].

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