TyG-BMI Index Calculator
TyG-BMI Index Calculator
Combine the TyG index with body mass index for a closer surrogate of clamp-measured insulin resistance than TyG alone.
TyG-BMI Index
TyG × BMIFasting triglycerides 150 mg/dL, fasting glucose 95 mg/dL, BMI 28 kg/m²
Formula
- TG, G₀
- fasting triglycerides and fasting glucose, mg/dL
- BMI
- body mass index, kg/m²
- why multiply
- BMI is added as a linear multiplier rather than combined by regression — a deliberately simple construction
Worked example
Fasting triglycerides 150 mg/dL, fasting glucose 95 mg/dL, BMI 28 kg/m²
TyG = ln(150 × 95 ÷ 2) = ln(7,125) = 8.871
TyG-BMI = 8.871 × 28 = 248.4
TyG-BMI compared with TyG alone
| TyG | TyG-BMI | |
|---|---|---|
| Inputs | Triglycerides, glucose | Triglycerides, glucose, BMI |
| Correlation with clamp IR | Moderate | Generally stronger |
| What it mostly reflects | Dysglycaemia and dyslipidaemia | The above, plus adiposity |
| Interpretation | Population-specific | Population-specific |
What adding BMI buys, and what it costs
TyG-BMI is exactly what its name says: the TyG index multiplied by body mass index. The construction is deliberately simple — no separate regression coefficients, just a product — and several validation studies have found that this simple combination correlates more closely with insulin resistance measured by the euglycaemic-hyperinsulinaemic clamp than TyG alone. The improvement makes physiological sense, since adiposity, particularly visceral fat, is itself a major driver of insulin resistance and adds information that triglycerides and glucose alone do not fully capture.
The cost of that improvement is conceptual. Once BMI is folded in, TyG-BMI is substantially an adiposity measure with a metabolic adjustment, rather than a purely metabolic index. A very high BMI will push the score up even in someone whose glucose and triglycerides are unremarkable, and a lean patient with genuinely poor insulin sensitivity may score lower than the biology would suggest. It is best read as a composite screening tool rather than as a pure measure of insulin action, and its value is in identifying people worth investigating further rather than in replacing a clamp or an OGTT-based index.
As with TyG, thresholds are cohort-specific rather than fixed. The bands used here follow the ranges most often reported in Asian and North American validation cohorts, but treat them as a general guide rather than a diagnostic cut-off for an individual patient.
Frequently asked questions
How is TyG-BMI calculated?
Multiply the TyG index (the natural log of triglycerides times glucose, divided by two) by body mass index in kg/m².
Is TyG-BMI more accurate than TyG alone?
It generally correlates more closely with clamp-measured insulin resistance, because adiposity is itself a driver of resistance and adds information TyG alone does not capture.
Is TyG-BMI mainly a measure of insulin resistance or of body weight?
Both, and that is its main limitation. Adding BMI improves the statistical fit but makes the score substantially reflect adiposity as well as glycaemic and lipid status.
What TyG-BMI value suggests insulin resistance?
Values above roughly 200 to 250 are commonly used, but the threshold is cohort-specific and has not been standardised across populations.
Related calculators
References
- Er LK et al. Triglyceride glucose-body mass index is a simple and clinically useful surrogate marker for insulin resistance in nondiabetic individuals. PLoS One. 2016;11(3):e0149731.
- Guerrero-Romero F et al. The product of triglycerides and glucose, a simple measure of insulin sensitivity: comparison with the euglycemic-hyperinsulinemic clamp. J Clin Endocrinol Metab. 2010;95(7):3347–51.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.