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Weight & Metabolicapproved

CCK-8

Cholecystokinin Octapeptide
Weight & Metabolic
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Category
Weight & Metabolic
Evidence grade
A
PubMed records
32,441
Female-tagged
6,446
Sex-analysis
13
CAS
—
A
Evidence grade A, Approved indication with 6446 indexed studies that included female subjects. How grades work →
Female evidence: Extrapolated
CCK-8: of 32,441 PubMed records, 6,446 are tagged as including female subjects and 13 carry a sex-analysis tag.Counts reflect PubMed records as of 2026-07-21. “Female” uses the Female MeSH filter and “sex-analysis” the Sex Factors MeSH filter, automated proxies pending manual study-level review. Methodology →

Overview

Cholecystokinin-8, or CCK-8, is the biologically active C-terminal octapeptide of cholecystokinin, one of the classical gut hormones. Because this short fragment carries most of the parent hormone's signaling activity, it has long served as a practical research material in appetite and gut-brain studies.

In research models, CCK-8 has been studied for its association with satiety signaling, gastrointestinal function, and gut-brain communication through CCK receptor subtypes. Investigators examining feeding behavior and digestive physiology have used it as a reference peptide for probing satiety mechanisms.

For a metabolic research catalog, CCK-8 is notable as a well-characterized endogenous satiety signal, which makes it a useful comparator in appetite studies. Whether these mechanisms translate the same way across female physiology remains an open research question; our evidence review tracks how many of the underlying studies included women.

Summary

CCK-8 is the active octapeptide of cholecystokinin, a gut hormone central to satiety and digestion. Its synthetic form (sincalide) is FDA-approved as a diagnostic agent for gallbladder and pancreatic function; the broader satiety literature is not analyzed for female-specific therapeutic outcomes.

Evidence in women

Menstrual cycle
Unstudied
Appetite and satiety shift across the cycle, but CCK-8 response has not been mapped by cycle phase in controlled study.
Pregnancy & lactation
Contraindicated
Diagnostic labeling cautions against use in pregnancy due to possible uterine stimulation; lactation effects not established.
Hormonal interactions
Unstudied
No controlled data on interactions with reproductive or thyroid hormones.
Perimenopause & menopause
Unstudied
No perimenopause- or menopause-specific analyses.
Sex differences
Unstudied
Women are included in the satiety and diagnostic literature, but therapeutic outcomes are not systematically analyzed by sex.

Mechanism

Activates CCK1/CCK2 receptors to stimulate gallbladder contraction, pancreatic secretion, and satiety signaling.

Reported dosing & routes

◐

We don't give dosing or medical advice. The figures below describe what was used in published research, not a recommendation. Decide with your clinician.

Reported range (literature)Sincalide is given by weight-based intravenous infusion for diagnostic gallbladder testing per its approved label.
Routesintravenous
Female-specific dosingNot established

Contraindications: gallstones with obstruction; pregnancy (may stimulate uterine contraction, per diagnostic labeling caution)

Side effects

Reported in the research literature. Sex-specific incidence has not been separately analysed in the available records.

abdominal crampingnauseaurge to defecate

CCK-8 reconstitution calculator

Enter this vial's amount, the bacteriostatic water you add, and a target amount to get the concentration and the U-100 syringe units to draw. Handling arithmetic for research use, not a dose recommendation.

Reconstitution

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Draw for CCK-8

5
units on a U-100 insulin syringe
020406080100
U-100 insulin syringe — 1 mL = 100 units
That's 0.05 mL drawn to the 5-unit mark.
Concentration5 mg/mL (5,000 mcg/mL)
Volume to draw0.05 mL
Doses per vial40

Reference chart at 5 mg/mL

Target amountVolume (mL)U-100 units
100 mcg0.02 mL2
250 mcg0.05 mL5
500 mcg0.1 mL10
750 mcg0.15 mL15
1000 mcg0.2 mL20

Research-use arithmetic only. This tool converts a vial amount, diluent volume, and a target amount into a concentration and syringe draw for laboratory handling. It is not dosing guidance, a recommendation, or a claim of safety or efficacy, and it does not account for overfill, dead space, or peptide purity. Nothing here is medical advice. “U-100” means 100 units = 1 mL; confirm your syringe graduation before measuring. See the reconstitution & storage handbook for handling detail.

Frequently asked questions

Answers drawn only from CCK-8's research facts and, where reviewed, its sex-disaggregated evidence. Nothing here is medical advice, dosing, or a claim of safety or efficacy.

What is CCK-8?

CCK-8, also known as Cholecystokinin Octapeptide, is a research compound in our weight metabolic category. CCK-8 is the active octapeptide of cholecystokinin, a gut hormone central to satiety and digestion.

Is CCK-8 studied in women?

CCK-8: of 32,441 PubMed records, 6,446 are tagged as including female subjects and 13 carry a sex-analysis tag. We grade this extrapolated: women appear in the record, but no study is tagged for a sex-specific analysis, so female-relevant conclusions are inferred from mixed or male data rather than measured in women. See our methodology.

Has CCK-8 been studied during pregnancy or breastfeeding?

Contraindicated. Diagnostic labeling cautions against use in pregnancy due to possible uterine stimulation; lactation effects not established. This is not a safety clearance or a recommendation. Vera, our research chat, deliberately hard-stops on pregnancy, breastfeeding, and trying-to-conceive questions rather than answer them.

What evidence grade does CCK-8 have, and why?

CCK-8 carries evidence grade A. Approved indication with 6446 indexed studies that included female subjects.. Grades are derived from the research record, never hand-assigned; see how grades work.

Is there a female-specific dose for CCK-8?

No. A female-specific dose for CCK-8 is not established, and this site does not provide dosing or medical advice. Any figures we show describe what published research used, not a recommendation. Decide anything about use with a qualified clinician.

How is CCK-8 administered in research?

In the published literature, CCK-8 is administered via intravenous. Reported dose ranges on the Dosing tab describe what studies used for laboratory research, not a protocol for people. We don't provide dosing.

What side effects have been reported for CCK-8?

Effects reported in the research literature include abdominal cramping, nausea, urge to defecate. Sex-specific incidence has not been separately analysed in the available records, so these are not broken out for women.

How should CCK-8 be stored and handled?

CCK-8 sold for research is supplied as a lyophilized (freeze-dried) powder. Lyophilized peptides are generally kept cold and dry, at roughly -20°C for longer-term storage and 2-8°C short-term, protected from light. Once reconstituted they are typically refrigerated and used within a short window, avoiding repeated freeze-thaw cycles. This is general laboratory handling for research use only, not a directive for human use. Always follow the handling and purity details on the product's Certificate of Analysis.

Where can I buy CCK-8 for research?

CCK-8 is not currently listed by our research-use partner, Aurevena Research, but their catalog carries related compounds. Code research15 applies 15% off. We may earn a commission when you purchase through this link, at no extra cost to you. Products are for laboratory research use only.

Browse the Aurevena catalog
Research-use supplier: CCK-8 isn't currently listed by our research-use vendor. Their catalog carries related compounds. Code research15 for 15% off, applied automatically at checkout. We may earn a commission when you purchase through this link, at no extra cost to you. Products are for laboratory research use only.
Browse the catalog →

Citations (PMID)

29999817 · 18582529

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Educational information for laboratory and research use only. Not medical advice, a recommendation, or a claim of safety or efficacy; no personal dosing. “Unstudied” means no qualifying study was found, not that a compound is safe or unsafe.