Fasting insulin

Reference ranges

Optimal ranges are tighter than standard lab ranges and reflect functional-medicine targets, not the populations they were derived from. Reference bands depend on sex, age, and circumstance — Juno's lab analysis layers your profile context onto the printed range when you paste a value.

Peptide relevance

Fasting insulin paired with fasting glucose is the most sensitive readout for insulin resistance (HOMA-IR derived = fasting insulin × fasting glucose / 405). GLP-1 agonists (tirzepatide, semaglutide) typically lower fasting insulin within 8-12 weeks as insulin sensitivity improves. GH-axis peptides (CJC-1295, ipamorelin, tesamorelin, MK-677): GH transiently increases insulin resistance, so fasting insulin can RISE while on these — opposite direction of GLP-1s. 5-amino-1MQ may improve insulin sensitivity in animal models; no consistent human data. KEY CAVEATS: fast 10-12h before draw, no exercise in prior 24h (transient insulin sensitivity drop), and recent illness skews readings.

Peptides that influence this marker

Documented to affect this marker. Click through for the full evidence-tiered profile.

• CJC-1295
  GHRH analog

  GH-axis activation transiently raises fasting insulin (first 4-8 weeks)

• Ipamorelin
  GHRP / ghrelin mimetic

  GH-axis activation transiently raises fasting insulin (first 4-8 weeks)

• MK-677 (Ibutamoren)
  Non-peptide ghrelin mimetic (small molecule)

  Raises fasting insulin meaningfully within weeks — flag for impaired tolerance

• Tier 1 — Human RCTSemaglutide↓· by 12 weeks
  GLP-1 receptor agonist

  Lowers fasting insulin via improved insulin sensitivity

• Tesamorelin
  GHRH analog

  Modest transient insulin resistance during GH-axis activation

• Tier 1 — Human RCTTirzepatide↓· 12 weeks
  GLP-1 / GIP dual agonist

  Lowers fasting insulin via improved insulin sensitivity