Homocarnosine
The brain's GABA-based cousin of carnosine — a histidine dipeptide tied to GABA handling and seizure control, and an antioxidant. A research molecule, not a drug
Homocarnosine is a small dipeptide the body makes, closely related to carnosine and anserine but built from a different first piece: instead of beta-alanine it uses GABA, the brain's main inhibitory neurotransmitter, joined to histidine (so it is gamma-aminobutyryl-L-histidine). Unlike carnosine, which is abundant in muscle, homocarnosine is concentrated in the central nervous system, where it appears to act as part of the brain's GABA system — a reservoir or handling intermediate for GABA. Its brain concentration can be watched non-invasively by magnetic resonance spectroscopy, and in people with epilepsy, brain homocarnosine tracks with GABA and with seizure control, rising on anticonvulsant therapy. Like the rest of the histidine-dipeptide family it is also an antioxidant: it scavenges reactive carbonyl compounds and helps protect cells and DNA from oxidative damage. Rare inherited disorders of its metabolism (homocarnosinosis, serum carnosinase deficiency) are known. Homocarnosine is studied as an endogenous brain dipeptide; it is not an approved medicine and has not been given to people as a treatment.
No established human dose Details ↓
Recommended Dosing
No established human dose
Homocarnosine is a dipeptide the brain makes; it has never been given to people as a treatment. Human studies measure it in brain or cerebrospinal fluid rather than administering it, and cell and animal work uses experimental concentrations that do not carry over to people.
Work out syringe units → · New to syringes? · All dosing data ↓ · Dose and vial tracker · Is this vial OK?
What is it?
The histidine dipeptides are a small family — carnosine, anserine, balenine and homocarnosine — each a histidine joined to a short amino-acid partner. Homocarnosine is the odd one out in a useful way: its partner is not beta-alanine (as in carnosine) but GABA, gamma-aminobutyric acid, the brain's principal inhibitory neurotransmitter. That makes homocarnosine gamma-aminobutyryl-L-histidine, and it ties the peptide directly to the brain's GABA system. It is concentrated in the central nervous system rather than in muscle, and animal work shows it can be synthesised in tissue when GABA is supplied, by the same carnosine-synthesising machinery.
Its most studied role is as a brain GABA marker. Magnetic resonance spectroscopy can measure homocarnosine in the living brain, and in people with epilepsy its level moves with brain GABA. In a study of epilepsy patients, the anticonvulsant gabapentin raised brain GABA quickly and, with daily therapy, increased homocarnosine (and a related metabolite, pyrrolidinone) as well — supporting the long-standing observation that higher brain homocarnosine accompanies better seizure control, whether as a cause or a sign of it.
Homocarnosine also shares the antioxidant personality of its family. In a cell model of ischemia, homocarnosine (like carnosine) protected neuron-like PC12 cells from oxygen-glucose-deprivation injury, acting as an antioxidant neuroprotectant. It sequesters acrolein — a reactive, neurotoxic aldehyde that is elevated in Alzheimer's-disease brain — forming adducts that detoxify it, and it protects DNA from oxidative strand breaks driven by iron and hydrogen peroxide. These carbonyl- and radical-scavenging actions are of interest for the oxidative stress seen in neurodegeneration.
Because homocarnosine sits in the GABA pathway, its metabolism matters clinically. It can be measured in cerebrospinal fluid, where its level is age-dependent, and dedicated assays were developed partly to study inherited defects of the GABA pathway — including homocarnosinosis (accumulation of homocarnosine) and serum carnosinase deficiency. These rare conditions underline that homocarnosine is a real node in human neurochemistry, not merely a dietary curiosity.
Homocarnosine is an endogenous brain dipeptide and a research subject. Unlike carnosine and anserine it is not generally sold or taken as a supplement, no study has given homocarnosine to people as a treatment, it is approved nowhere, and anything offered under its name is an unregulated research chemical. Nothing here is a dose or a therapy; this page records what the published science says.
Mechanism of Action
Homocarnosine is a brain histidine dipeptide made from GABA and histidine. It functions in the GABA system (its brain level tracks GABA and seizure control) and, like carnosine and anserine, acts as an antioxidant that scavenges reactive carbonyls and radicals to protect neurons and DNA.
GABA-system dipeptide
Built from GABA + histidine and concentrated in the CNS; brain homocarnosine tracks GABA and rises with anticonvulsant therapy (PMIDs 32361909, 10840398).
Antioxidant neuroprotection
Protects neuron-like cells from ischemic oxidative injury, comparable to the histidine-dipeptide family's antioxidant action (PMID 11992473).
Carbonyl / radical scavenging
Sequesters the reactive aldehyde acrolein and protects DNA from iron/peroxide oxidative damage (PMIDs 14505328, 21034531).
Published Research
These are studies of homocarnosine read from their PubMed records on November 7, 2026: an animal study of its GABA-driven synthesis and identity; a human epilepsy study showing brain homocarnosine rises with anticonvulsant therapy; cell and biochemical studies of its antioxidant neuroprotection and carbonyl/radical scavenging; and a cerebrospinal-fluid assay used to study GABA-pathway disorders. Homocarnosine has not been given to people as a treatment; the evidence is human-marker, animal and in-vitro work.
Dietary GABA drives homocarnosine synthesis (mice); identity
Homocarnosine (gamma-aminobutyryl-L-histidine) was proposed as an imidazole dipeptide analogous to carnosine but built on GABA; feeding mice GABA markedly increased skeletal-muscle homocarnosine (without changing carnosine, anserine or beta-alanine), and a GABA-transaminase inhibitor further raised circulating GABA and tissue homocarnosine — showing homocarnosine is synthesised from GABA in tissue (an animal study establishing its identity and biosynthesis).
Gabapentin raises brain GABA and homocarnosine in epilepsy patients
Using brain magnetic resonance spectroscopy in epilepsy patients, a first dose of gabapentin promptly raised brain GABA, and daily therapy increased both GABA and homocarnosine (and pyrrolidinone) — consistent with homocarnosine accumulating with sustained anticonvulsant therapy and accompanying partial seizure protection (a human-marker study; homocarnosine was measured, not administered).
Homocarnosine is neuroprotective in a cell ischemia model
In PC12 cells subjected to oxygen-glucose deprivation and reoxygenation, homocarnosine (like carnosine) provided substantial neuroprotection against the ischemic, reactive-oxygen-species-mediated injury — comparable to a known antioxidant and absent in a non-oxidative toxicity model — indicating the histidine dipeptides act as antioxidant neuroprotectants (an in-vitro study).
Homocarnosine sequesters the reactive aldehyde acrolein
Both carnosine and homocarnosine quenched acrolein — a neurotoxic lipid-peroxidation aldehyde elevated in Alzheimer's-disease brain — by most after a few hours, forming adducts at the beta-alanine/GABA and histidine residues; the work demonstrated a mechanism by which these brain dipeptides detoxify reactive carbonyls (an in-vitro study).
Homocarnosine protects DNA from iron/peroxide oxidative damage
Carnosine and homocarnosine prevented ferritin/hydrogen-peroxide-mediated DNA strand breakage, inhibited hydroxyl-radical generation and reduced the mutagenicity induced by the reaction — suggesting these histidine dipeptides can protect DNA under the oxidative conditions implicated in neurodegeneration (an in-vitro study).
Measuring homocarnosine in cerebrospinal fluid (GABA-pathway disorders)
A sensitive isotope-dilution LC-MS/MS assay quantified homocarnosine in cerebrospinal fluid, where its concentration is age-dependent; the method was developed to study inherited defects of the GABA pathway, including homocarnosinosis and serum carnosinase deficiency — underlining homocarnosine's place in human neurochemistry (an analytical/clinical study).
No Established Human Dose
Homocarnosine is a dipeptide the brain makes; it has never been given to people as a treatment. Human studies measure it in brain or cerebrospinal fluid rather than administering it, and cell and animal work uses experimental concentrations 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 10840398, PMID 11992473, PMID 16309980.
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 Homocarnosine 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 Homocarnosine 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 Homocarnosine, 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 Homocarnosine stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Homocarnosine. 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 brain-compartment dipeptide handled within the GABA pathway. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Homocarnosine. Results reported in the studies are under Published Research.
Source: half-life: PMID 16309980.
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 homocarnosine to people; It is part of the GABA system; its brain level is a marker studied in epilepsy, not an administered therapy (PMID 10840398) — an observation, not a safety profile; Inherited disorders of its metabolism exist (homocarnosinosis, serum carnosinase deficiency), reflecting its role in human neurochemistry (PMID 16309980); Material offered online as 'homocarnosine' 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 Homocarnosine. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Homocarnosine is an endogenous brain dipeptide that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research status and its biology”).
Interactions
Unknown: a PubMed search for human interaction studies of Homocarnosine (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 Homocarnosine 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; it checks the measured mass against Homocarnosine's expected mass, 240.3 Da, from this entry's molecular data. 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, and FDA GSRS and ChEMBL hold no drug record for homocarnosine (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
Homocarnosine is an endogenous brain dipeptide that has not been given to people as a drug, so there is no human safety profile; the points below reflect that research status and its biology.
Contraindications & Cautions
Homocarnosine has no approved use and no label. These points reflect its research status.
Legal Status
Homocarnosine is an endogenous brain dipeptide studied as a research compound; it is not a drug and is not approved in any country.
Frequently Asked Questions
?What is homocarnosine?
A dipeptide made from GABA and histidine (gamma-aminobutyryl-L-histidine), a brain-concentrated member of the carnosine/anserine histidine-dipeptide family. It is the GABA analog of carnosine (PMID 32361909).
?Why is it linked to epilepsy?
Homocarnosine sits in the brain's GABA system, and its brain level (measurable by MRS) tracks GABA and seizure control, rising with anticonvulsant therapy such as gabapentin (PMID 10840398).
?Is it an antioxidant like carnosine?
Yes. Homocarnosine scavenges reactive carbonyls (e.g. acrolein) and protects neurons and DNA from oxidative damage in cell and biochemical studies (PMIDs 14505328, 21034531, 11992473).
?Can I take it as a supplement?
No. Unlike carnosine and anserine, homocarnosine is not an established supplement; it is an endogenous brain dipeptide, not an approved medicine, and has not been given to people as a treatment. Grey Peptides lists no sellers and recommends no source.
References
- [animal] Kumrungsee T, et al. "Dietary GABA induces endogenous synthesis of a novel imidazole peptide homocarnosine in mouse skeletal muscles." Amino Acids, 2020;52(5):743-753. PMID: 32361909.
- [clinical-trial] Petroff OA, et al. "Effects of gabapentin on brain GABA, homocarnosine, and pyrrolidinone in epilepsy patients." Epilepsia, 2000;41(6):675-80. PMID: 10840398.
- [mechanism] Tabakman R, et al. "Neuroprotective effects of carnosine and homocarnosine on pheochromocytoma PC12 cells exposed to ischemia." J Neurosci Res, 2002;68(4):463-9. PMID: 11992473.
- [mechanism] Carini M, et al. "Acrolein-sequestering ability of endogenous dipeptides: characterization of carnosine and homocarnosine/acrolein adducts by electrospray ionization tandem mass spectrometry." J Mass Spectrom, 2003;38(9):996-1006. PMID: 14505328.
- [mechanism] Kang JH. "Protective effects of carnosine and homocarnosine on ferritin and hydrogen peroxide-mediated DNA damage." BMB Rep, 2010;43(10):683-7. PMID: 21034531.
- [mechanism] Jansen EE, et al. "A novel, quantitative assay for homocarnosine in cerebrospinal fluid using stable-isotope dilution liquid chromatography-tandem mass spectrometry." J Chromatogr B Analyt Technol Biomed Life Sci, 2006;830(2):196-200. PMID: 16309980.
- [other] Homocarnosine is the dipeptide gamma-aminobutyryl-L-histidine, a histidine (imidazole) dipeptide built on GABA rather than beta-alanine, concentrated in the central nervous system; its identity and family relationship to carnosine and anserine 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 homocarnosine. It is an endogenous brain dipeptide studied in research, not a drug; FDA GSRS and ChEMBL hold no drug record for it.
Sources & Citations
The six studies carded above were read from their PubMed records on November 7, 2026. Homocarnosine's identity (gamma-aminobutyryl-L-histidine, the GABA analog of carnosine), its CNS localisation and GABA-system role, its link to brain GABA and seizure control in epilepsy, its antioxidant neuroprotection and carbonyl/radical scavenging, and the GABA-pathway disorders are from the studies carded here; the absence of US approval or a drug record from Drugs@FDA, openFDA, FDA GSRS and ChEMBL was checked the same day. Homocarnosine is one of the histidine dipeptides, with carnosine, anserine and balenine. 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.