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Research Only Metabolic & Weight Loss

Cholecystokinin

also known as: CCK, CCK-8, CCK-33, CCK-58, Pancreozymin

The original satiety signal — a gut-brain peptide that tells you to stop eating, stimulates digestion, and modulates anxiety and pain in the CNS.

A family of gut-brain peptides (CCK-8 through CCK-58) released by I-cells of the duodenum after a meal that reduce food intake via vagal CCK1 receptors, stimulate gallbladder contraction and pancreatic enzyme secretion, and act as an anxiogenic neuropeptide in the brain via CCK2 receptors.

Mechanism of action

Binds CCK1R (peripheral gut — mediates satiety, gallbladder contraction, pancreatic enzyme secretion) and CCK2R (primarily CNS — modulates anxiety, pain perception, and memory). CCK1R activation on vagal afferents transmits the satiety signal to the nucleus tractus solitarius.

Primary uses

  • Endogenous post-meal satiety signaling
  • Gallbladder contraction and pancreatic enzyme secretion
  • CNS neuropeptide (anxiety modulation, pain perception)
  • Diagnostic use: sincalide for gallbladder function testing

Typical dosing

0.02 mcg/kg single diagnostic dose (IV (sincalide only))

Sincalide 0.02 mcg/kg IV is used diagnostically for cholecystography. Not used therapeutically for satiety.

Regulatory status

Sincalide (Kinevac, a synthetic CCK-8 analog) is FDA-approved as a diagnostic agent for gallbladder contraction studies and pancreatic function testing, but not as a therapeutic.

References

  1. [pubmed] Gibbs J, Young RC, Smith GP. "Cholecystokinin decreases food intake in rats." J Comp Physiol Psychol. 1973;84(3):488-495.
  2. [review] Rehfeld JF. "Cholecystokinin -- from local gut hormone to ubiquitous messenger." Front Endocrinol. 2017;8:47.

Related peptides

Peptide YY

The postprandial 'stop eating' signal — an endogenous satiety peptide that reduces appetite via the Y2 receptor, and a pharmacological target for next-generation obesity drugs.

Ghrelin

The 'hunger hormone' — the only known circulating appetite stimulant, and the endogenous ligand that GHRP-2, GHRP-6, and MK-677 were designed to mimic.

Neuropeptide Y

The brain's most abundant neuropeptide — a 36-amino-acid master regulator of appetite, stress resilience, and anxiety that connects metabolic and cognitive peptide networks.

GLP-2

GLP-1's sibling hormone — a potent intestinal growth factor that drives gut epithelial repair, and the native molecule behind teduglutide (Gattex).

Semaglutide

A once-weekly GLP-1 receptor agonist FDA-approved for type 2 diabetes and chronic weight management.
Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.