Bombesin
A 14-amino-acid peptide from toad skin that became a classic research tool: it curbs eating, acts on the stomach and body temperature, and gave its name to a family of mammalian gut-brain peptides and their receptors
Bombesin was pulled from the skin of a European toad in 1970 and turned out to be a remarkably active little peptide. Injected into animals, it is one of the most potent known suppressors of eating, it changes how the stomach secretes acid and protects its lining, and it lowers body temperature. Those effects made it a workhorse for studying how the gut talks to the brain. Bombesin itself is an amphibian peptide, but the body makes close mammalian relatives — gastrin-releasing peptide and neuromedin B — that act on the same receptors, now called the bombesin receptors. Because one of those receptors is heavily overproduced by prostate and breast cancers, radioactively tagged bombesin analogs are being developed to image those tumors. Bombesin is a research peptide and pharmacological probe — it is not an approved medicine, and it has been given to people only as a brief research infusion in appetite experiments, never as a treatment.
No established human dose Details ↓
Recommended Dosing
No established human dose
Bombesin is an amphibian research peptide, not a treatment, and no therapeutic dose exists. It has been given to people only as a brief intravenous infusion in controlled appetite experiments (for example to study satiety), not to treat any condition, and no regulator has approved a dose.
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What is it?
In 1970 the Italian pharmacologists Anastasi and Erspamer, who made a career of finding active peptides in frog and toad skin, isolated a 14-amino-acid peptide from the European fire-bellied toad Bombina bombina and named it bombesin. It proved to be strikingly potent across several systems, and it became one of the most studied peptides in the physiology of the gut and brain.
Its most famous action is on appetite. Given to animals — and, in a few careful studies, to people — bombesin produces satiety: it ends a meal early and brings on the normal behavioural signs of fullness. In sham-feeding rats, where food drains away before it can be absorbed, bombesin still suppressed eating, showing it acts as a genuine satiety signal rather than by filling the gut. In lean human volunteers, an infusion of bombesin reduced how much of a meal they ate and lowered their hunger, and did so independently of the other satiety hormone cholecystokinin.
Bombesin does much more than curb eating. In the stomach it regulates acid and gastrin release and, injected into the brain's fluid, it is the most potent peptide known to inhibit acid secretion while making the stomach lining more resistant to injury — a gastroprotective effect carried through sensory nerves, nitric oxide and increased mucosal blood flow. It lowers body temperature, especially in fasted or cold-exposed animals, and it influences grooming, memory and stress behaviour through receptors in the hypothalamus and amygdala.
Bombesin itself is not found in mammals; it is the amphibian prototype of a family. Humans make two close relatives, gastrin-releasing peptide (GRP) and neuromedin B (NMB), which carry out the family's actions through the bombesin receptors — GRP-receptor (BB2), NMB-receptor (BB1) and the orphan receptor BRS-3 (BB3). Because of the shared pharmacology, bombesin is used in the laboratory as a convenient probe for all of them.
The receptor link has become clinically important. The gastrin-releasing-peptide receptor is produced in large amounts by common cancers, notably prostate and breast cancer, so synthetic bombesin analogs carrying a radioactive tag are being developed to find those tumors on PET scans and, potentially, to deliver radiation to them. Earlier agonist tracers caused gut side effects, and the field has shifted to receptor antagonists that are better tolerated.
Bombesin is a research peptide and a pharmacological tool, not a medicine. It has been given to people only as a brief infusion in appetite experiments, it is approved nowhere, and material sold online as ‘bombesin’ is an unregulated research chemical. Nothing here is a dose or a therapy; this page records what the published science says about a peptide that shaped the study of gut-brain signalling.
Mechanism of Action
Bombesin works through the bombesin receptors — the same receptors the body's own GRP and neuromedin B use. Acting in the gut and brain, it signals satiety, shapes gastric function and body temperature, and, through one of those receptors, marks certain cancers.
Satiety signalling
Bombesin is a potent satiety agent: it ends meals early and brings on the behaviour of fullness in animals (PMID 7243611) and reduces food intake in people independently of cholecystokinin (PMID 8501156), acting through bombesin receptors in the gut-brain axis.
Gastric function and protection
Acting centrally it regulates gastric acid and gastrin and renders the stomach lining resistant to injury through sensory nerves, nitric oxide and increased mucosal blood flow (PMID 11090915), and it influences body temperature via the hypothalamus (PMID 2623011).
GRP-receptor and cancer
The family's GRP-receptor is overproduced by prostate and breast cancers, so radiolabeled bombesin analogs are built to image and potentially treat those tumors (PMID 34830920) — the main translational use of bombesin pharmacology.
Published Research
These are studies of bombesin read from their PubMed abstracts on November 5, 2026. The feeding work spans a small human infusion trial and classic rat studies of satiety and thermoregulation; the reviews cover the bombesin receptors and ligands, the brain-gut axis, and the radiolabeled bombesin analogs now used to image cancer. Bombesin has been given to people only as a research infusion, never as a treatment.
Bombesin reduces food intake in lean men
A double-blind study in nine lean healthy volunteers infused bombesin or saline before a carbohydrate-rich meal. During bombesin the amount eaten fell significantly (482 vs 602 g) and subjective satiety rose. Giving the cholecystokinin-receptor antagonist loxiglumide did not block the effect, showing bombesin curbs human food intake by a cholecystokinin-independent mechanism — a short research infusion, not a treatment.
Satiety in sham-feeding rats
In rats with gastric cannulas, intraperitoneal bombesin produced potent, dose-related suppression of both sham feeding (food draining away before absorption) and normal feeding, and elicited the behavioural sequence of normal satiety. Because sham feeding minimises gastric and post-absorptive signals, the result showed bombesin acts as a genuine satiety signal — a foundational finding in appetite research.
Bombesin-induced hypothermia
In food-deprived rats, bombesin lowered core body temperature, an effect potentiated by cold exposure and produced when bombesin was microinfused into the preoptic area of the anterior hypothalamus; it occurred in fasted and insulin-treated but not food-satiated rats. The study mapped bombesin's thermoregulatory action to a specific brain region and to the fasting state.
Radiolabeled bombesin analogs for cancer
A review of using the gastrin-releasing-peptide receptor — overproduced by prostate and breast cancers — as a target for radiolabeled bombesin analogs in cancer imaging and therapy. It traces the shift from agonist tracers, which caused abdominal side effects and poor clearance, to better-tolerated antagonists, and surveys the clinical progress and remaining limitations.
Bombesin receptors and ligands
An authoritative overview of the bombesin peptide and receptor field since bombesin's 1970 isolation from frog skin: the mammalian ligands GRP and NMB, the receptors (GRP-receptor, NMB-receptor and the orphan BRS-3), and their roles across physiology and disease including obesity and pruritus.
Bombesin and the brain-gut axis
A review of bombesin as the first peptide shown to act in the brain to influence gastric function and the most potent known inhibitor of acid secretion when given into the cerebrospinal fluid. It describes the hypothalamic, brainstem and spinal sites involved and the integrated, gastroprotective gastric response bombesin drives through autonomic pathways.
No Established Human Dose
Bombesin is an amphibian research peptide, not a treatment, and no therapeutic dose exists. It has been given to people only as a brief intravenous infusion in controlled appetite experiments (for example to study satiety), not to treat any condition, and no regulator has approved a dose. Animal studies used it by injection or brain infusion at microgram amounts that do not carry over to people, so no amount is printed here.
What this rests on: PMID 8501156, PMID 7243611, PMID 2623011.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Bombesin is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
Unknown: no human dose of Bombesin has been established (see No Established Human Dose below), so there is no amount to work out. The reconstitution calculator does the arithmetic for any vial, water and dose.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Bombesin, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Bombesin stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Bombesin. What the human studies gave and how is set out under No Established Human Dose.
What to expect, and when
How long it stays in the body: a half-life of short-acting; given by continuous infusion in human research studies. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Bombesin. Results reported in the studies are under Published Research.
Source: half-life: PMID 8501156.
Side effects, and when to stop or get help
From the Side Effects section: No therapeutic human safety data exist; human use has been short research infusions only (PMID 8501156); As a satiety agent it reduces food intake and hunger during infusion (PMID 8501156); In animals it lowers body temperature, especially when fasted or cold-exposed (PMID 2623011); Agonist radiolabeled bombesin analogs caused abdominal side effects, prompting a shift to antagonists (PMID 34830920). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Bombesin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Bombesin is a research peptide given to people only briefly in experiments, so there is no treatment safety profile; the points below reflect that research status”).
Interactions
Unknown: a PubMed search for human interaction studies of Bombesin (reviewed 2026-11-05) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Bombesin products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Research Chemical (Not a drug: Drugs@FDA and the openFDA label endpoint hold no record for bombesin (searched November 5, 2026)). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
Bombesin is a research peptide given to people only briefly in experiments, so there is no treatment safety profile; the points below reflect that research status.
Contraindications & Cautions
Bombesin has no approved use and no label. These points reflect its research-only status.
Legal Status
Bombesin is an amphibian research peptide studied as a pharmacological probe; it is not a drug and is not approved in any country.
Frequently Asked Questions
?What is bombesin?
A 14-amino-acid peptide first isolated from the skin of a European toad in 1970. It is the prototype of a family whose human members are gastrin-releasing peptide and neuromedin B, all acting on the bombesin receptors. It is best known as a potent satiety signal and a research tool.
?What does it do?
In animals and in a small human study it curbs eating and brings on satiety (PMIDs 7243611, 8501156); it regulates gastric acid and protects the stomach lining (PMID 11090915) and lowers body temperature (PMID 2623011). Its receptor is a target for cancer imaging (PMID 34830920).
?Has it been given to people?
Only as a brief research infusion. In lean volunteers, infused bombesin reduced food intake and hunger (PMID 8501156). It has never been used as a treatment, and radiolabeled bombesin analogs — not bombesin itself — are what is being tested clinically for cancer imaging.
?Is it approved or available to buy?
No. Bombesin is not a medicine, has no FDA application or label, and is approved nowhere. Material sold online as bombesin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [rct] Lieverse RJ, et al. "Bombesin reduces food intake in lean man by a cholecystokinin-independent mechanism." J Clin Endocrinol Metab, 1993;76(6):1495-8. PMID: 8501156.
- [animal] Martin CF, et al. "Bombesin elicits satiety in sham feeding rats." Peptides, 1980;1(2):131-4. PMID: 7243611.
- [animal] Babcock AM, et al. "Bombesin-induced hypothermia in food-deprived rats." Pharmacol Biochem Behav, 1989;34(3):539-44. PMID: 2623011.
- [review] Mansi R, et al. "Radiolabeled Bombesin Analogs." Cancers (Basel), 2021;13(22). PMID: 34830920.
- [review] Ramos-Álvarez I, et al. "Insights into bombesin receptors and ligands: Highlighting recent advances." Peptides, 2015;72:128-44. PMID: 25976083.
- [review] Martinez V, et al. "Bombesin and the brain-gut axis." Peptides, 2000;21(11):1617-25. PMID: 11090915.
- [other] PubChem, read November 5, 2026: bombesin, CID 16201612, C71H110N24O18S, MW 1619.9, CAS 31362-50-2; a 14-amino-acid amidated peptide, pGlu-Gln-Arg-Leu-Gly-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2. https://pubchem.ncbi.nlm.nih.gov/compound/16201612
- [other] Bombesin was isolated from the skin of the European fire-bellied toad (Bombina bombina) and named in 1970; it is the prototype of the bombesin-like peptide family, whose mammalian members are gastrin-releasing peptide (GRP) and neuromedin B (NMB), acting on the bombesin receptors (reviewed in the receptor review carded on this page, read November 5, 2026).
- [other] US FDA, Drugs@FDA and the drug label endpoint (openFDA), searched November 5, 2026: no application and no label record for bombesin. It is an amphibian research peptide, not a registered drug; it has been given to people only as a short research infusion in physiology experiments.
Sources & Citations
The six studies carded above were read from their PubMed records on November 5, 2026. Structure and identifiers come from PubChem (CID 16201612); bombesin's 1970 isolation and its place in the bombesin-peptide family are from the receptor review carded here; the absence of US approval and of a drug record from Drugs@FDA and openFDA was checked the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.