Insulin sensitivity / HOMA-IR
Reads: Insulin sensitivity
You want it high: strong insulin sensitivity is central to weight, energy and longevity.
What this marker reads
Insulin sensitivity — how readily cells respond to insulin, the linchpin of metabolic health.
What a named body publishes
Each line below is the sentence the issuing body wrote, carried with its own identifier. Nothing here interprets your result — it states what was published, for whom, and by whom.
HOMA-IR
“In 1,167 healthy adults from the population-based FINRISK/DILGOM cohort the upper 95th percentile of HOMA-IR was 1.9 (90% CI 1.8-2.0).”
Use of HOMA-IR to diagnose non-alcoholic fatty liver disease: a population-based and inter-laboratory study · Diabetologia · 2017 DOI 10.1007/s00125-017-4340-1
“In 459 healthy adults from the population-based FIN-D2D cohort the upper 95th percentile of HOMA-IR was 2.0 (90% CI 1.9-2.2).”
Use of HOMA-IR to diagnose non-alcoholic fatty liver disease: a population-based and inter-laboratory study · Diabetologia · 2017 DOI 10.1007/s00125-017-4340-1
Your laboratory reads your result against its own assay, and this page does not do that for it. What is above is what a named body published and for whom; what is below is the machinery the marker reads and the formulas witnessed on it.
What moves it
Visceral fat lowers it.
Pooling observational studies, visceral fat mass showed the strongest correlation with HOMA-IR of any fat depot or anthropometric measure (r = 0.570, 95% CI 0.424-0.687), ahead of total fat, BMI and waist circumference, so greater visceral fat tracks with lower insulin sensitivity. doi 10.1038/srep18495 · PMID 26686961
Fasting metabolic hormone raises it.
Kharitonenkov 2005, J Clin Invest 115:1627 — FGF21 improves glucose and insulin; transgenic FGF21 yields a lean, insulin-sensitive phenotype. PMID 15902306. Gain-of-function in vivo: liver-directed FGF21 transgenic mice (ApoE promoter, ~50-fold higher hepatic FGF21 than fasted wild-type) showed significant reductions in serum cholesterol, glucose and insulin — lower insulin at lower glucose is the signature of improved sensitivity rather than suppressed secretion. Independently replicated by a second group generating FGF21 transgenics with the same promoter. Mechanism is partly central, not purely hepatic: beta-Klotho is expressed in discrete hypothalamic areas whose deletion abrogates FGF21's metabolic effects, and central FGF21 requires intact sympathetic tone to act at the periphery. PMID 15902306
Training load raises it.
Regular aerobic and resistance training improve insulin sensitivity and glycemia in type 2 diabetes — meta-analyses show 0.5-0.7% HbA1c reductions, with resistance training giving 10-15% improvements in insulin sensitivity. PMC8802999
Fasting response raises it.
Caloric restriction improves insulin sensitivity — a core, repeatedly reviewed metabolic effect of CR (Calorie restriction, SIRT1 and metabolism, Nat Rev Mol Cell Biol 2005). The 2-year human calerie trial confirmed the underlying program in skeletal muscle: sirtuin signaling, mitochondrial biogenesis, enhanced autophagy and reduced inflammation (doi 10.1111/acel.13963). Intermittent fasting consistently improves insulin sensitivity, lipid profiles and body composition by promoting fat oxidation while maintaining lean mass — the lean-mass clause matters, because it separates fasting from simple energy deficit. Leptin sensitivity improves alongside insulin sensitivity. The reviewers themselves state the limit: most data come from animal studies OR short-term human trials, raising questions about generalisability to long-term clinical outcomes, and the degree to which autophagy induction produces observable improvement in human metabolic health is still not fully understood. doi 10.1111/acel.13963
Ceramide load lowers it.
Holland 2007, Cell Metab 5:167 — the sphingolipid ceramide is the common intermediate linking saturated fat and glucocorticoids to insulin resistance; inhibiting ceramide synthesis restores glucose tolerance. PMID 17339025. Two independent and fully separable mechanisms, named to the residue: ceramides block AKT by (1) PP2A dephosphorylating its activating residues, and (2) PKC-zeta phosphorylating an inactivating T34 residue inside the AKT PH domain, which blocks AKT translocation rather than its phosphorylation. Downstream, GLUT4 translocation fails in muscle and adipose and hepatic gluconeogenesis is inadequately suppressed. Human, with clamp: in visceral and subcutaneous adipose from 439 subjects, CerS6 expression correlated positively with BMI, body fat and hyperglycemia and inversely with insulin sensitivity measured by EUGLYCAEMIC-HYPERINSULINAEMIC clamp — the reference method, not a surrogate index. Three limits that the sources state themselves. (1) much of the mechanism rests on artefact-prone tools: the early cultured-cell work used cell-permeable short-chain ceramides with cytotoxic properties, often at unphysiologic concentrations. (2) the PP2A arm fails its in-vivo test: pharmacological inhibition of PP2A in rats paradoxically worsened hepatic insulin resistance despite activating AKT — the opposite of what the model predicts. (3) which arm dominates depends on the cell: the PKC-zeta route predominates in L6 myotubes and in primary human muscle cells, whereas PP2A predominates in C2C12. And the causal link is explicitly unsettled: an enzyme generating ceramide close enough to the insulin receptor to suppress it directly has not yet been identified. Chain length decides the sign: long-chain C16:0/C18:0 ceramides track myocardial infarction, heart failure and cardiovascular mortality, while very-long-chain C22:0/C24:0 are neutral OR potentially protective. 'Ceramide' is not one thing. PMID 17339025
Calms inflammation lowers it.
Hotamisligil 1993, Science 259:87 — adipose TNF-α (an NF-κB-driven inflammatory cytokine) blocks insulin action; neutralizing TNF-α restores insulin-stimulated glucose uptake. doi:10.1126/science.7678183. The demonstration is loss-of-function and that is its strength: TNF-alpha mRNA was induced in adipose tissue across four different rodent obesity/diabetes models, protein rose locally and systemically, and neutralizing TNF-alpha in obese fa/fa rats caused a significant increase in peripheral glucose uptake in response to insulin. Species — the landmark paper is entirely rodent. The human counterpart is a separate, later study (Hotamisligil 1995, PMID 7738205): adipose TNF-alpha mRNA in 18 control vs 19 obese premenopausal women, and that paper states plainly that the mechanisms linking obesity to insulin resistance and diabetes in humans remain largely unknown. And the review found disconfirming human evidence that must travel with this edge: subcutaneous adipose tissue was shown to release interleukin-6 but not TNF-alpha in vivo in humans (Mohamed-Ali 1997, J Clin Endocrinol Metab 82:4196-4200). If adipose TNF-alpha is not exported systemically in people, its action is LOCAL/PARACRINE and the systemic rodent story does not transfer intact. The edge stands on the rodent loss-of-function; the human systemic route is contested. doi 10.1126/science.7678183. · PMID 7738205
Slows carb absorption raises it.
By decreasing postprandial hyperglycemia and improving insulin sensitivity, acarbose therapy reduces fasting and postprandial serum insulin, fasting plasma glucose and HbA1c (PMID 12086760; doi 10.1016/S0140-6736(02)08905-5; PMID 14703948; doi 10.1002/14651858.CD005061.pub2; PMC8771266). doi 10.1016/S0140-6736(02 · PMID 12086760 · PMC8771266
Appetite & sugar hormone raises it.
Drucker 2006, Cell Metab 3:153 — GLP-1 stimulates glucose-dependent insulin secretion from pancreatic β-cells.
Fat-burning hormone raises it.
Yamauchi 2001, Nat Med 7:941 — adiponectin reverses insulin resistance by lowering muscle and liver triglyceride. doi 10.1038/90984
Blocks new fat cells raises it.
PPARγ–adiponectin review 2005 — PPARγ activation improves insulin sensitivity, largely via adiponectin. PMID 15711577
What it moves
It lowers Type 2 diabetes.
Insulin resistance is the major pathophysiological feature of type 2 diabetes; obesity-driven release of non-esterified fatty acids, glycerol, hormones and pro-inflammatory cytokines from adipose tissue is what produces it. PMID 17167471
It lowers PCOS.
Insulin resistance with compensatory hyperinsulinemia is present in 65-95% of women with PCOS and is considered a major driver of its pathophysiology — it participates directly in the development of hyperandrogenemia and reproductive dysfunction, and insulin-sensitizing treatment is an established therapeutic route. PMC9832677
It lowers Fasting insulin.
As insulin sensitivity falls, the pancreas compensates by secreting more — which is why fasting insulin rises long before fasting glucose does, and why it is the earlier warning (PMC11906131, PMC9255858). Note, and it matters: the arrow is not settled in one direction. Hyperinsulinemia is conventionally read as the compensation for resistance, but evidence shows chronically elevated insulin can itself drive resistance — fasting insulin correlates negatively with insulin-receptor mRNA in human skeletal muscle across >450 samples, and prolonged insulin exposure attenuates AKT and ERK signaling in myotubes. Treat this as a reinforcing loop, not a one-way street. PMC11906131
It raises Reproductive trigger hormone.
Kisspeptin neurons are influenced by leptin and insulin (excitatory) and by ghrelin and adiponectin (inhibitory) — this is the junction where metabolic state reaches the reproductive axis, and it explains why obesity and metabolic disease suppress the axis centrally rather than at the testis (PMC8482951). stated as a regulatory influence on these neurons; the quantitative contribution relative to sex-steroid feedback is not established in the sources read here. PMC8482951
It raises Cardiac output.
In the early stages of diabetic cardiomyopathy, metabolic disturbances such as defective insulin signaling, excessive circulating insulin, impaired glucose uptake, elevations in myocardial fatty acid uptake, and mitochondrial dysfunction promote cardiac morphological and functional changes. The route is specified three ways: hyperglycemia, insulin resistance, and hyperinsulinemia have all been associated with calcium overload; insulin resistance is detrimental to mitochondria via excessive ROS production and altered cardiomyocyte calcium handling; and it can increase FFA flux through CD36. This is heart disease that begins before any coronary narrowing, which is precisely what a map built around atherosclerosis alone would miss. doi 10.1016/j.jacc.2006.07.007 · PMC10932393
It raises Memory & focus.
Brain insulin resistance sits at the CROSSROAD between metabolic and neurodegenerative disease. Insulin acts on the hippocampus, a brain area playing a pivotal role in learning and memory and primarily affected in Alzheimer’s disease. A named molecular step: insulin induces phosphorylation of GSK3-beta on the inhibitory serine 9 residue, thus reducing its enzymatic activity. doi 10.1007/s10522-025-10300-4 · PMC6685093
It raises Brain adaptability.
Molecular evidence links alteration of hippocampal insulin sensitivity with changes of both adult neurogenesis and synaptic plasticity, with crosstalk between insulin and neurotrophin signaling - which is BDNF, already drawn into this pathway. doi 10.1007/s10522-025-10300-4 · PMC6685093
It raises Muscle.
Insulin, another important anabolic hormone, is also involved through a similar pathway. However, myocyte sensitivity to insulin is significantly reduced during aging, which may be related to the deposition of ectopic lipids such as ceramides in muscle, impaired mitochondrial function, and decreased endothelial function. Three named causes of the resistance, and all three are nodes here. doi 10.3390/ijms26146740 · PMC13074595
It raises Kidney.
The reviewers say this has been missed: the impact of insulin resistance and compensatory hyperinsulinemia on kidney function, and their contribution to CKD, have largely been overlooked in people with OR without diabetes. And the kidney is an insulin target organ in its own right: beyond its classical metabolic targets - muscle, liver and adipocytes - insulin has an essential role in kidney metabolism and physiology, regulating podocyte integrity, tubular sodium handling and gluconeogenesis. In resistance these are disrupted, leading to glomerular hyperfiltration, proteinuria, sodium retention, progressive kidney injury. doi 10.1038/s41581-026-01066-0 · PMC11725408
It lowers Clears liver fat.
Named across five reviews of the cardiovascular-renal-hepatic-metabolic syndrome as part of the shared mechanism set: ectopic fat accumulation triggered by metabolic reprogramming, oxidative stress and inflammation induced by energy overload, modified lipids, UREMIC toxins, and senescence, as well as insulin resistance pathways activated by pro-inflammatory factors and lipotoxic products, collectively exacerbate simultaneous hepatic and renal injury. doi 10.1038/s41581-026-01066-0 · PMC11725408
Formulas that modulate it
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