Fasting Insulin

Advanced wellness

also insulin, fasting

What it isInsulin is the hormone the pancreas releases to push glucose into cells and shut down liver glucose output. Fasting insulin measures how much your pancreas is secreting at rest, when no food has arrived for at least 10–12 hours.

DoesDrives glucose uptake into muscle, fat, and liver; switches off fat burning; promotes growth and storage; regulates sodium retention.

GoodLow fasting insulin signals high insulin sensitivity — the metabolic substrate of lean physiology, durable energy, and a long healthspan.

BadHigh fasting insulin is the earliest fingerprint of insulin resistance, rising years before glucose or A1c move. Sustained hyperinsulinemia drives visceral fat, fatty liver, hypertension, cancer growth signals, polycystic ovaries, and brain atrophy.

Standard

2.6–24.9 µIU/mL.

Optimal

2–3 µIU/mL (lower is good)

Modifiers

Rises with weight gain, stress, poor sleep, late eating; suppressed by fasting and ketogenic diets.

How to optimize

Lifestyle: Resistance training is the single biggest lever — muscle is the largest insulin-sensitive tissue. Zone 2 cardio 150+ minutes/week. Sleep, walking after meals, and time-restricted eating compound.
Diet: Cut sugar, refined grains, and seed oils. Build meals on protein, fibrous vegetables, and whole-food fats. Most people drop fasting insulin by 30–50% within 6 weeks of low-carb whole food eating.
Supplements: Berberine (500mg 3×/day pre-meal), inositol (myo + d-chiro, 2g 2×/day), magnesium glycinate (300mg/day), alpha-lipoic acid (600mg/day).
Peptides: Tirzepatide and semaglutide cut fasting insulin sharply by improving sensitivity and reducing the demand. MOTS-c improves insulin signaling.
Drugs: Metformin, GLP-1 agonists (semaglutide, tirzepatide, retatrutide), SGLT2 inhibitors, pioglitazone.

within Blood Sugar & Metabolic