Glucose Metabolism Blood Markers

Fragment cleaved from proinsulin and released into the blood in equal (equimolar) amounts with endogenous insulin. Reflects how much insulin the pancreatic beta cells are actually producing and, unlike injected insulin, is not present in pharmaceutical insulin.

PED: Strong PED relevance. Because injected (exogenous) insulin contains no C-peptide, this test separates the body's own insulin output from injected insulin: a bodybuilder using exogenous insulin will show high blood insulin but low or suppressed C-peptide, whereas insulin resistance from GH or MK-677 drives high endogenous insulin AND high C-peptide. C-peptide is the better gauge of true beta-cell output and is more stable than insulin (longer half-life, no first-pass liver clearance). Use it alongside fasting insulin, glucose, and HOMA-IR when screening for the insulin resistance that accompanies growth hormone, MK-677, and high-calorie growth phases.

Blood sugar level. Elevated levels indicate diabetes risk.

PED: GH use can elevate fasting glucose and potentially cause insulin resistance. Important to monitor on GH, especially at higher doses. High carb diets can affect non-fasting values.

Average blood sugar over 2-3 months. Best marker for long-term glucose control.

PED: GH use can worsen HbA1c over time, indicating insulin resistance. More reliable than single glucose readings as it reflects 2-3 months average. High haematocrit from AAS can affect accuracy of some HbA1c assays. Target <5.5% for optimal metabolic health.

IFCC-standardised HbA1c measurement. Same marker as HbA1c % but in SI units. Normal: <42 mmol/mol. Pre-diabetes: 42-47. Diabetes: >=48. Conversion: mmol/mol = (% - 2.15) x 10.929.

PED: Equivalent to HbA1c % — same clinical significance. GH use can worsen HbA1c over time, indicating insulin resistance. High haematocrit from AAS can affect accuracy of some HbA1c assays. Australian labs report both units; mmol/mol is the IFCC standard.

Hormone that controls blood sugar. High levels indicate insulin resistance.

PED: GH use increases insulin resistance, requiring more insulin to control blood sugar. Some athletes use exogenous insulin (extremely dangerous -- can cause fatal hypoglycaemia). Low fasting insulin with normal glucose is optimal and indicates good insulin sensitivity.

Calculated index of insulin resistance derived from fasting glucose and fasting insulin. Lower values indicate better insulin sensitivity. The most practical tool for detecting early GH/peptide-induced metabolic dysfunction.

PED: Auto-calculated when both Fasting Glucose and Fasting Insulin are present in a blood test. Formula: (Glucose mmol/L x Insulin mIU/L) / 22.5. Lean, muscular athletes typically have lower baseline HOMA-IR (0.5-1.0) than sedentary adults. This means even 'normal' values (1.5-2.0) can represent a meaningful shift on GH or MK-677. Track the trend, not just the absolute number. A HOMA-IR that doubles from 0.8 to 1.6 over a GH cycle is a stronger signal than a single reading of 1.6 in isolation. GH, MK-677, and other GH-releasing peptides are the primary drivers of HOMA-IR elevation in this population. The index catches insulin resistance weeks before fasting glucose alone would flag a problem.