What the TG/HDL ratio shows
The triglyceride to HDL ratio divides triglycerides by HDL cholesterol. When triglycerides rise and HDL falls, the liver makes more triglyceride-rich particles and LDL tends to become small and dense — a pattern common in insulin resistance. That is why the ratio is used as an indirect marker of insulin resistance1,2 and it was associated with myocardial infarction in a classic case-control study.4
mg/dL vs mmol/L: careful
Unlike the Castelli index, the TG/HDL ratio depends on the unit. The conversion factors differ (triglycerides: ÷ 88.57; HDL: ÷ 38.67), so the same person has a ratio about 2.3 times smaller in mmol/L.
| Example | mg/dL | mmol/L |
|---|---|---|
| Triglycerides | 180 | 2,03 |
| HDL | 42 | 1,09 |
| TG/HDL | 4,29 | 1,87 |
| AIP | 0,27 (same in both units) | |
Cut-offs
| Group | Cut-off in mg/dL | ≈ in mmol/L | Study |
|---|---|---|---|
| Overweight adults | ≥ 3,0 | ≥ 1,3 | McLaughlin 20031 |
| Women | ≥ 2,5 | ≥ 1,1 | Salazar 20122 |
| Men | ≥ 3,5 | ≥ 1,5 | Salazar 20122 |
These cut-offs come from specific populations and may vary with ethnicity and age. They help raise suspicion of insulin resistance; they are not diagnostic.
AIP
O atherogenic index of plasma (AIP) is log₁₀ of the TG/HDL ratio in mmol/L. Dobiášová and Frohlich proposed it because it correlates with LDL particle size.3 Ranges used: below 0.11 low; 0.11–0.21 intermediate; above 0.21 high.
Limitations
The ratio does not replace cardiovascular risk scores or guideline LDL and non-HDL targets.6,7,8 Triglycerides vary a lot with food, alcohol and fasting; above 400 mg/dL (4.5 mmol/L), repeat the test and talk to your doctor. For the full picture, also use the Castelli index.
Frequently asked questions
What is a good triglyceride to HDL ratio?
There is no single ideal value. In studies using mg/dL, ratios below 2.5 were the most favorable; insulin-resistance cut-offs were around 2.5 in women and 3.5 in men (about 3.0 in overweight adults).
Does the TG/HDL ratio change in mmol/L?
Yes. Because the conversion factors for triglycerides (88.57) and HDL (38.67) differ, the mmol/L ratio is about 2.3 times smaller. The calculator shows both and applies the right cut-offs.
What is AIP?
The atherogenic index of plasma: the logarithm of the TG/HDL ratio in mmol/L. It correlates with LDL particle size — higher values mean more small, dense particles.
Does a high TG/HDL mean diabetes?
No. It is an indirect marker of insulin resistance and must be read together with glucose, HbA1c, waist, blood pressure and clinical history.
Can I improve this ratio?
Usually, losing abdominal fat, regular exercise, less sugar and alcohol and better sleep lower triglycerides and may raise HDL. The right plan is individual.
Read also
- Castelli indexTC/HDL, LDL/HDL and non-HDL cholesterol
- Chromium picolinateEvidence on glucose and body composition
- Metformin and inflammationWhat the studies say
- Losing fat, not muscleProtein, training and pace of loss
- Obesity and inflammationHow excess fat affects health
- ApoB or total cholesterol?The best particle marker
References
- McLaughlin T, Abbasi F, Cheal K, et al. Use of metabolic markers to identify overweight individuals who are insulin resistant. Ann Intern Med. 2003;139:802-9. doi:10.7326/0003-4819-139-10-200311180-00007
- Salazar MR, Carbajal HA, Espeche WG, et al. Relation among the plasma triglyceride/high-density lipoprotein cholesterol concentration ratio, insulin resistance, and associated cardio-metabolic risk factors in men and women. Am J Cardiol. 2012;109:1749-53. doi:10.1016/j.amjcard.2012.02.016
- Dobiášová M, Frohlich J. The plasma parameter log(TG/HDL-C) as an atherogenic index: correlation with lipoprotein particle size and esterification rate in apoB-lipoprotein-depleted plasma (FERHDL). Clin Biochem. 2001;34:583-8. doi:10.1016/S0009-9120(01)00263-6
- Gaziano JM, Hennekens CH, O’Donnell CJ, et al. Fasting triglycerides, high-density lipoprotein, and risk of myocardial infarction. Circulation. 1997;96:2520-5. doi:10.1161/01.CIR.96.8.2520
- Millán J, Pintó X, Muñoz A, et al. Lipoprotein ratios: physiological significance and clinical usefulness in cardiovascular prevention. Vasc Health Risk Manag. 2009;5:757-65. doi:10.2147/vhrm.s6269
- Rached FH, et al. Diretriz Brasileira de Dislipidemias e Prevenção da Aterosclerose – 2025. Arq Bras Cardiol. 2025. doi:10.36660/abc.20250640
- Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias. Eur Heart J. 2020;41:111-88. doi:10.1093/eurheartj/ehz455
- 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia. Circulation. 2026. doi:10.1161/CIR.0000000000001423
Want help reading your lab results?
Online consultation for patients in Brazil and abroad.
Book a teleconsultationWhat the TG/HDL ratio shows
The triglyceride to HDL ratio divides triglycerides by HDL cholesterol. When triglycerides rise and HDL falls, the liver makes more triglyceride-rich particles and LDL tends to become small and dense — a pattern common in insulin resistance. That is why the ratio is used as an indirect marker of insulin resistance1,2, and it was associated with myocardial infarction in a classic case-control study.4
mg/dL vs mmol/L: careful
Unlike the Castelli index, the TG/HDL ratio depends on the unit. The conversion factors differ (triglycerides: ÷ 88.57; HDL: ÷ 38.67), so the same person has a ratio about 2.3 times smaller in mmol/L.
| Example | mg/dL | mmol/L |
|---|---|---|
| Triglycerides | 180 | 2.03 |
| HDL | 42 | 1.09 |
| TG/HDL | 4.29 | 1.87 |
| AIP | 0.27 (same in both units) | |
Cut-offs
| Group | Cut-off in mg/dL | ≈ in mmol/L | Study |
|---|---|---|---|
| Overweight adults | ≥ 3.0 | ≥ 1.3 | McLaughlin 20031 |
| Women | ≥ 2.5 | ≥ 1.1 | Salazar 20122 |
| Men | ≥ 3.5 | ≥ 1.5 | Salazar 20122 |
These cut-offs come from specific populations and may vary with ethnicity and age. They help raise suspicion of insulin resistance; they are not diagnostic.
AIP
The atherogenic index of plasma (AIP) is log₁₀ of the TG/HDL ratio in mmol/L. Dobiášová and Frohlich proposed it because it correlates with LDL particle size.3 Ranges used: below 0.11 low; 0.11–0.21 intermediate; above 0.21 high.
Limitations
The ratio does not replace cardiovascular risk scores or guideline LDL and non-HDL targets.6,7,8 Triglycerides vary a lot with food, alcohol and fasting; above 400 mg/dL (4.5 mmol/L), repeat the test and talk to your doctor. For the full picture, also use the Castelli index.
FAQ
What is a good triglyceride to HDL ratio?
There is no single ideal value. In studies using mg/dL, ratios below 2.5 were the most favorable; insulin-resistance cut-offs were around 2.5 in women and 3.5 in men (about 3.0 in overweight adults).
Does the TG/HDL ratio change in mmol/L?
Yes. Because the conversion factors for triglycerides (88.57) and HDL (38.67) differ, the mmol/L ratio is about 2.3 times smaller. The calculator shows both and applies the right cut-offs.
What is AIP?
The atherogenic index of plasma: the logarithm of the TG/HDL ratio in mmol/L. It correlates with LDL particle size — higher values mean more small, dense particles.
Does a high TG/HDL mean diabetes?
No. It is an indirect marker of insulin resistance and must be read together with glucose, HbA1c, waist, blood pressure and clinical history.
Can I improve this ratio?
Usually, losing abdominal fat, regular exercise, less sugar and alcohol and better sleep lower triglycerides and may raise HDL. The right plan is individual.
Read also
- Castelli risk indexTC/HDL, LDL/HDL and non-HDL cholesterol
- Semaglutide dose calculatorClicks, mL and cost per pen
- Losing fat, not muscleProtein, training and pace · in Portuguese
- ApoB or total cholesterol?The best particle marker · in Portuguese
References
- McLaughlin T, Abbasi F, Cheal K, et al. Use of metabolic markers to identify overweight individuals who are insulin resistant. Ann Intern Med. 2003;139:802-9. doi:10.7326/0003-4819-139-10-200311180-00007
- Salazar MR, Carbajal HA, Espeche WG, et al. Relation among the plasma triglyceride/high-density lipoprotein cholesterol concentration ratio, insulin resistance, and associated cardio-metabolic risk factors in men and women. Am J Cardiol. 2012;109:1749-53. doi:10.1016/j.amjcard.2012.02.016
- Dobiášová M, Frohlich J. The plasma parameter log(TG/HDL-C) as an atherogenic index: correlation with lipoprotein particle size and esterification rate in apoB-lipoprotein-depleted plasma (FERHDL). Clin Biochem. 2001;34:583-8. doi:10.1016/S0009-9120(01)00263-6
- Gaziano JM, Hennekens CH, O’Donnell CJ, et al. Fasting triglycerides, high-density lipoprotein, and risk of myocardial infarction. Circulation. 1997;96:2520-5. doi:10.1161/01.CIR.96.8.2520
- Millán J, Pintó X, Muñoz A, et al. Lipoprotein ratios: physiological significance and clinical usefulness in cardiovascular prevention. Vasc Health Risk Manag. 2009;5:757-65. doi:10.2147/vhrm.s6269
- Rached FH, et al. Diretriz Brasileira de Dislipidemias e Prevenção da Aterosclerose – 2025. Arq Bras Cardiol. 2025. doi:10.36660/abc.20250640
- Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias. Eur Heart J. 2020;41:111-88. doi:10.1093/eurheartj/ehz455
- 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia. Circulation. 2026. doi:10.1161/CIR.0000000000001423
Want help reading your lab results?
Online consultations (in Portuguese, English or Spanish) for patients in Brazil and abroad.
Book a teleconsultationWhat the TG/HDL ratio shows
The triglyceride to HDL ratio divides triglycerides by HDL cholesterol. When triglycerides rise and HDL falls, the liver makes more triglyceride-rich particles and LDL tends to become small and dense — a pattern common in insulin resistance. That is why the ratio is used as an indirect marker of insulin resistance1,2 and it was associated with myocardial infarction in a classic case-control study.4
mg/dL vs mmol/L: careful
Unlike the Castelli index, the TG/HDL ratio depends on the unit. The conversion factors differ (triglycerides: ÷ 88.57; HDL: ÷ 38.67), so the same person has a ratio about 2.3 times smaller in mmol/L.
| Example | mg/dL | mmol/L |
|---|---|---|
| Triglycerides | 180 | 2,03 |
| HDL | 42 | 1,09 |
| TG/HDL | 4,29 | 1,87 |
| AIP | 0,27 (same in both units) | |
Cut-offs
| Group | Cut-off in mg/dL | ≈ in mmol/L | Study |
|---|---|---|---|
| Overweight adults | ≥ 3,0 | ≥ 1,3 | McLaughlin 20031 |
| Women | ≥ 2,5 | ≥ 1,1 | Salazar 20122 |
| Men | ≥ 3,5 | ≥ 1,5 | Salazar 20122 |
These cut-offs come from specific populations and may vary with ethnicity and age. They help raise suspicion of insulin resistance; they are not diagnostic.
AIP
The atherogenic index of plasma (AIP) is log₁₀ of the TG/HDL ratio in mmol/L. Dobiášová and Frohlich proposed it because it correlates with LDL particle size.3 Ranges used: below 0.11 low; 0.11–0.21 intermediate; above 0.21 high.
Limitations
The ratio does not replace cardiovascular risk scores or guideline LDL and non-HDL targets.6,7,8 Triglycerides vary a lot with food, alcohol and fasting; above 400 mg/dL (4.5 mmol/L), repeat the test and talk to your doctor. For the full picture, also use the Castelli index.
Frequently asked questions
What is a good triglyceride to HDL ratio?
There is no single ideal value. In studies using mg/dL, ratios below 2.5 were the most favorable; insulin-resistance cut-offs were around 2.5 in women and 3.5 in men (about 3.0 in overweight adults).
Does the TG/HDL ratio change in mmol/L?
Yes. Because the conversion factors for triglycerides (88.57) and HDL (38.67) differ, the mmol/L ratio is about 2.3 times smaller. The calculator shows both and applies the right cut-offs.
What is AIP?
The atherogenic index of plasma: the logarithm of the TG/HDL ratio in mmol/L. It correlates with LDL particle size — higher values mean more small, dense particles.
Does a high TG/HDL mean diabetes?
No. It is an indirect marker of insulin resistance and must be read together with glucose, HbA1c, waist, blood pressure and clinical history.
Can I improve this ratio?
Usually, losing abdominal fat, regular exercise, less sugar and alcohol and better sleep lower triglycerides and may raise HDL. The right plan is individual.
Read also
- Castelli indexTC/HDL, LDL/HDL and non-HDL cholesterol
- Semaglutide dose calculatorClicks, mL and cost per pen
- Losing fat, not muscleProtein, training and pace of loss
- ApoB or total cholesterol?The best particle marker · in Portuguese
References
- McLaughlin T, Abbasi F, Cheal K, et al. Use of metabolic markers to identify overweight individuals who are insulin resistant. Ann Intern Med. 2003;139:802-9. doi:10.7326/0003-4819-139-10-200311180-00007
- Salazar MR, Carbajal HA, Espeche WG, et al. Relation among the plasma triglyceride/high-density lipoprotein cholesterol concentration ratio, insulin resistance, and associated cardio-metabolic risk factors in men and women. Am J Cardiol. 2012;109:1749-53. doi:10.1016/j.amjcard.2012.02.016
- Dobiášová M, Frohlich J. The plasma parameter log(TG/HDL-C) as an atherogenic index: correlation with lipoprotein particle size and esterification rate in apoB-lipoprotein-depleted plasma (FERHDL). Clin Biochem. 2001;34:583-8. doi:10.1016/S0009-9120(01)00263-6
- Gaziano JM, Hennekens CH, O’Donnell CJ, et al. Fasting triglycerides, high-density lipoprotein, and risk of myocardial infarction. Circulation. 1997;96:2520-5. doi:10.1161/01.CIR.96.8.2520
- Millán J, Pintó X, Muñoz A, et al. Lipoprotein ratios: physiological significance and clinical usefulness in cardiovascular prevention. Vasc Health Risk Manag. 2009;5:757-65. doi:10.2147/vhrm.s6269
- Rached FH, et al. Diretriz Brasileira de Dislipidemias e Prevenção da Aterosclerose – 2025. Arq Bras Cardiol. 2025. doi:10.36660/abc.20250640
- Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias. Eur Heart J. 2020;41:111-88. doi:10.1093/eurheartj/ehz455
- 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia. Circulation. 2026. doi:10.1161/CIR.0000000000001423
Want help reading your lab results?
Online consultation for patients in Brazil and abroad.
Book a teleconsultation