Fasting Insulin

Glucose Metabolism marker

Insulin

Fasting Insulin

Category: Glucose Metabolism
Unit: mIU/L

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

PED Notes

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.

When high

Supplements:

  • Berberine -- 500mg 2-3x/day (before carb meals)
  • Alpha-Lipoic Acid (ALA) -- 300-600mg/day

Medical:

  • Metformin -- 500-1000mg/day if supplements insufficient

Lifestyle:

  • Reduce refined carbs, increase fibre
  • If on GH, consider reducing dose
  • Fasting and time-restricted eating can improve insulin sensitivity

Pharmacological options (when fasting insulin remains elevated despite metformin):

  • Semaglutide / Tirzepatide / Retatrutide -- 0.25-2.4mg, 2.5-15mg, or investigational dose subQ weekly; reduce fasting insulin by 30-50% via insulin sensitisation and modest weight loss; first-line for GH-induced hyperinsulinaemia
  • Pioglitazone -- 15-30mg/day; PPAR-gamma agonist, direct insulin sensitiser; useful when GLP-1 or metformin is insufficient; weight gain and oedema are notable side effects
  • Acarbose -- 25-100mg with main carb meals; reduces postprandial glucose load and downstream insulin demand
  • Empagliflozin / Dapagliflozin (SGLT2 inhibitors) -- 10-25mg/day; cardiorenal protection in addition to glucose lowering
  • Reduce or pause exogenous GH -- GH directly antagonises insulin and is the dominant driver of elevated fasting insulin in this population; dose reduction is often the most effective single intervention
  • All require physician oversight; monitor renal function, glucose, and weight response

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Frequently Asked Questions

Reference Ranges

Standard Range

2 - 25 mIU/L

VitalMetrics Range

2 - 12 mIU/L

Statistics