Apidaecin
A honeybee antimicrobial peptide that kills bacteria without bursting them — it jams the ribosome instead. A research compound, not a drug
Apidaecin is an antimicrobial peptide from the honeybee, and it works in a fundamentally different way from most of the peptides in this encyclopedia. Instead of punching holes in bacterial membranes, apidaecin is 'non-lytic': it is a short, proline- and arginine-rich peptide (a proline-rich antimicrobial peptide, or PrAMP) that bacteria actively import through their own transporters, after which it binds inside the ribosome — the cell's protein-making machine — and jams it. Specifically, apidaecin traps the release factors that normally let a finished protein be released, freezing ribosomes at stop codons and shutting down the completion of protein synthesis. Because it targets an internal machine rather than the membrane, apidaecin is mainly active against Gram-negative bacteria (which have the right transporters) and is gentle on host cells, a combination that makes it an attractive antibiotic lead. Synthetic apidaecin analogs are widely studied, and the natural peptide is used as a feed additive to improve gut health in poultry. Apidaecins are research peptides; they are not approved medicines and have not been given to people as a treatment.
No established human dose Details ↓
Recommended Dosing
No established human dose
Apidaecins are honeybee research peptides; none has been given to people as a treatment. The work is in bacteria, cultured cells and animals (including livestock feed trials), often with synthetic analogs, at experimental amounts that do not carry over to people.
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What is it?
Insects fight infection with antimicrobial peptides, and the honeybee's apidaecin, first described in 1989, has become the model for a whole mechanistic class: the proline-rich antimicrobial peptides, or PrAMPs. Apidaecin is short — about eighteen residues — and, true to the family name, unusually rich in proline and arginine. What sets it apart from the frog-, fish- and crab-skin peptides elsewhere in this encyclopedia is that it does not kill bacteria by breaking their membranes.
Instead, apidaecin is non-lytic and acts on an internal target. Bacteria take it up through their own membrane transporters, and once inside it binds in the ribosome's nascent-peptide exit tunnel. There it does something remarkable: it lets the ribosome reach a stop codon and then traps the release factor (RF1 or RF2) that would normally free the finished protein, locking the ribosome in place and blocking the recycling of the protein-making machinery. High-resolution and large-scale mutagenesis studies have mapped exactly which of apidaecin's residues make this work: screening hundreds of thousands of variants showed which positions are essential for arresting the terminating ribosome, and structure-guided chemistry has produced highly modified analogs that keep the activity.
This mechanism has two practical consequences. First, apidaecin's spectrum is shaped by uptake, so it is mainly active against Gram-negative bacteria (such as Escherichia coli and other Enterobacteriaceae) that carry the right transporters, though it also shows activity against some Gram-positives in direct comparisons against clinical blood-culture strains. Second, because it targets a bacterial machine rather than the membrane, apidaecin is relatively non-toxic to host cells, which is a central advantage for antibiotic development and the reason synthetic analogs such as Api137, Api802 and Api806 are so heavily studied.
Apidaecin is also moving into practical use as a livestock feed additive. Dietary apidaecin improved growth, gut structure, nutrient absorption and immune markers in broilers, and in laying hens it improved intestinal health, shifted the gut microbiota toward beneficial bacteria and cut Salmonella loads in the birds and on eggshells — a food-safety as well as a growth-promotion role. Researchers have even engineered bacteriophages to carry apidaecin sequences, exploring synergy between phages and the peptide. These are laboratory and animal studies, not treatments given to people.
Through all of this, apidaecins remain research peptides. No published study has given an apidaecin to people as a treatment, none is approved anywhere, and material sold online under these names is an unregulated research chemical. Nothing here is a dose or a therapy; this page records what the published science says.
Mechanism of Action
Apidaecin is a short, proline- and arginine-rich honeybee antimicrobial peptide (a PrAMP) that is NON-LYTIC: bacteria import it, and it binds the ribosome exit tunnel to trap release factors and arrest ribosomes at stop codons, blocking translation termination. Mainly active against Gram-negative bacteria, with low host toxicity; widely engineered and used as a feed additive.
Honeybee host defense (PrAMP)
A short proline- and arginine-rich antimicrobial peptide of honeybee immunity; natural variants (apidaecin 1a/1b, B) and synthetic analogs (Api137, Api802/806) (PMIDs 37603874, 38953159).
Ribosome / translation-termination block
Imported by bacterial transporters, binds the ribosomal exit tunnel and traps release factors RF1/RF2, arresting ribosomes at stop codons — a non-lytic mechanism (PMIDs 37603874, 38953159).
Gram-negative spectrum, low host toxicity
Uptake-dependent activity mainly against Gram-negative bacteria with low host-cell toxicity; used as a livestock feed additive against Salmonella (PMIDs 41623671, 41604325).
Published Research
These are studies of apidaecins read from their PubMed records on November 7, 2026: a comparison of apidaecin B with temporin A against clinical blood-culture strains; two livestock-feed studies (laying hens and broilers) of dietary apidaecin on gut health and Salmonella; a large mutagenesis study of apidaecin-like peptides arresting the terminating ribosome; a structure-activity study of apidaecin's ribosome mechanism; and an apidaecin-bacteriophage engineering study. The evidence is in bacteria, cells and animals; apidaecins have not been given to people as a treatment.
Apidaecin B and temporin A against clinical blood-culture strains
Apidaecin B and the frog peptide temporin A were tested against clinical bacterial strains isolated from blood cultures; apidaecin B was bactericidal against Escherichia coli and temporin A against staphylococci, supporting both as alternative antibacterial agents that warrant further optimisation of stability and delivery (an in-vitro study).
Dietary apidaecin improves gut health and cuts Salmonella in laying hens
Apidaecin added to the feed of laying hens improved intestinal structure, shifted the gut microbiota toward beneficial short-chain-fatty-acid-producing bacteria and raised gut immune markers; after a Salmonella Typhimurium challenge it reduced bacterial loads in the birds and on eggshells, and inhibited Salmonella adhesion to gut cells in vitro — a food-safety result.
Mapping apidaecin variants that arrest the terminating ribosome
Screening a library of roughly 350,000 apidaecin variants in bacteria identified which residues are essential for the peptide's on-target function — binding the ribosome exit tunnel and trapping release factors at stop codons — and found many multi-substituted variants that retained or improved antibacterial activity, greatly expanding the known ribosome-arresting PrAMP sequences (an in-vitro study).
Dietary apidaecin Api-PR19 improves growth and gut in broilers
A synthetic apidaecin (Api-PR19) added to broiler feed improved growth performance, nutrient digestibility, intestinal structure, gut-barrier gene expression and secretory IgA, and reshaped the small-intestinal microbiota — performing comparably to an antibiotic growth promoter as a feed additive (a poultry study).
Structure-activity relationships of apidaecin's ribosome mechanism
Modifying the residues of apidaecin responsible for stabilising the ribosome-apidaecin-tRNA-release-factor complex produced a highly modified analog that kept both its antimicrobial activity and its interaction with the translation-termination machinery — establishing structure-guided optimisation of this non-lytic peptide (an in-vitro study).
Bacteriophages engineered to carry apidaecin sequences
Lytic T7 bacteriophages were genetically modified to carry apidaecin-derived sequences as a proof of concept for combining phages with a peptide antibiotic; synthetic apidaecin analogs added to phage-infected cultures prevented or delayed growth of phage-resistant bacteria, though phage-encoded expression needs further optimisation (an in-vitro study).
No Established Human Dose
Apidaecins are honeybee research peptides; none has been given to people as a treatment. The work is in bacteria, cultured cells and animals (including livestock feed trials), often with synthetic analogs, at experimental amounts that do not carry over to people. No regulator has approved any dose, and no published human dose exists, so no amount is printed here.
What this rests on: PMID 41623671, PMID 41604325, PMID 37603874.
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 Apidaecin 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 Apidaecin 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 Apidaecin, 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 Apidaecin stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Apidaecin. 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 not established for humans; a short linear peptide subject to proteolysis, analogs engineered for stability. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Apidaecin. Results reported in the studies are under Published Research.
Source: half-life: PMID 37603874.
Side effects, and when to stop or get help
From the Side Effects section: No human adverse-event data exist: no published study has administered an apidaecin to people; Unlike membrane-disrupting peptides, apidaecin is non-lytic and relatively non-toxic to host cells, which is a research advantage — but this is laboratory and animal data, not human safety data; Its spectrum is mainly Gram-negative and uptake-dependent, so activity can be lost if bacteria change their peptide transporters (a resistance route studied in the lab, PMID 38953159); Material sold online as an 'apidaecin' is an unregulated research chemical of unverified content. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Apidaecin. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Apidaecins are research peptides that have not been given to people as drugs, so there is no human safety profile; the points below reflect that research status and their biology”).
Interactions
Unknown: a PubMed search for human interaction studies of Apidaecin (reviewed 2026-11-07) 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 Apidaecin 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 drugs: Drugs@FDA and the openFDA label endpoint hold no record, and FDA GSRS and ChEMBL hold no approved-drug record for apidaecin peptides (searched November 7, 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
Apidaecins are research peptides that have not been given to people as drugs, so there is no human safety profile; the points below reflect that research status and their biology.
Contraindications & Cautions
Apidaecins have no approved use and no label. These points reflect their research status.
Legal Status
Apidaecins are honeybee antimicrobial peptides used as research compounds; they are not drugs and are not approved in any country.
Frequently Asked Questions
?What is apidaecin?
A proline- and arginine-rich antimicrobial peptide from the honeybee, about 18 amino acids long, first described in 1989. It is the model 'proline-rich antimicrobial peptide' (PrAMP) (PMID 37603874).
?How is it different from other antimicrobial peptides?
It is non-lytic: instead of breaking bacterial membranes, bacteria import it and it binds the ribosome, trapping release factors and arresting ribosomes at stop codons to block protein-synthesis completion — so it is gentle on host cells (PMIDs 37603874, 38953159).
?What is it studied or used for?
As a non-lytic antibacterial lead (mainly against Gram-negative bacteria), with many synthetic analogs, and as a livestock feed additive that improves gut health and reduces Salmonella in poultry (PMIDs 41623671, 41604325).
?Is it approved or available to buy?
No apidaecin is an approved drug anywhere. They are honeybee research antimicrobial peptides; any feed-additive use is regulated separately from medicine. Material sold online as an apidaecin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [mechanism] Yayla İ, et al. "In vitro Antimicrobial Activities of Temporin A and Apidaecin B Peptides Against Clinical Strains Isolated from Blood Culture." J Clin Pract Res, 2025;47(2):223-226. PMID: 41623671.
- [animal] Ma H, et al. "Harnessing apidaecin capability to improve intestinal health and inhibit Salmonella Typhimurium transmission in laying hens." J Anim Sci, 2026;104. PMID: 41604325.
- [mechanism] Huang W, et al. "Sequence diversity of apidaecin-like peptides arresting the terminating ribosome." Nucleic Acids Res, 2024;52(15):8967-8978. PMID: 38953159.
- [animal] Wang C, et al. "Dietary apidaecin Api-PR19 addition enhances growth performance by regulating gut health and microbiota in broilers." Anim Biosci, 2024;37(9):1622-1634. PMID: 38575128.
- [mechanism] Skowron KJ, et al. "Structure-Activity Relationships of the Antimicrobial Peptide Natural Product Apidaecin." J Med Chem, 2023;66(17):11831-11842. PMID: 37603874.
- [mechanism] Ludwig T, et al. "Construction and Characterization of T7 Bacteriophages Harboring Apidaecin-Derived Sequences." Curr Issues Mol Biol, 2022;44(6):2554-2568. PMID: 35735615.
- [other] Apidaecin is a proline-rich antimicrobial peptide from the honeybee (Apis mellifera), first described by Casteels and colleagues (EMBO J, 1989) as an antibacterial peptide of bee immunity. Natural variants (apidaecin 1a/1b, apidaecin B) and many synthetic analogs (Api137, Api802/806) exist; its structure, mechanism and activities are described in the studies carded on this page (read November 7, 2026).
- [other] US FDA, Drugs@FDA and the openFDA label endpoint, searched November 7, 2026: no application and no label record for apidaecin peptides. They are honeybee research antimicrobial peptides, not drugs; FDA GSRS and ChEMBL hold no approved-drug record for them.
Sources & Citations
The six studies carded above were read from their PubMed records on November 7, 2026. Apidaecin's honeybee origin, its proline- and arginine-rich non-lytic structure, its ribosome-targeting mechanism (binding the exit tunnel and trapping release factors at stop codons), its mainly Gram-negative spectrum and low host toxicity, and its synthetic analogs and livestock-feed uses are from the studies carded here; the discovery is Casteels et al. (EMBO J, 1989). The absence of US approval or a drug record from Drugs@FDA, openFDA, FDA GSRS and ChEMBL 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.