Coluracetam
A racetam and choline-uptake enhancer (originally MKC-231 / BCI-540) with animal cognition data, one unpublished Phase 2 trial, and no published human efficacy evidence.
Coluracetam at a Glance
Coluracetam is a synthetic racetam that works as a high-affinity choline-uptake enhancer — it acts on the choline transporter CHT1 rather than on acetylcholinesterase, which makes it mechanistically distinct from the cholinergic drugs it is usually compared to. It was synthesised by Mitsubishi Tanabe Pharma in the early 1990s as candidate MKC-231, later licensed to BrainCells Inc. and redesignated BCI-540.
It does not occur in food. Every dose is exogenous exposure to a compound with no dietary counterpart and no deficiency state to correct.
The framing that matters most: coluracetam is an abandoned pharmaceutical asset sold as a research chemical, not a supplement that was ever evaluated for consumer use. Its reputation rests almost entirely on rodent studies from the 1990s and 2000s in which it rescued memory in animals with chemically induced cholinergic damage. That preclinical signal is real and reasonably well replicated — but it is a signal in damaged brains.
The honest bottom line: there is no published human efficacy evidence for anything. One Phase 2 depression trial completed and never reported results; development stopped. Treat every claim here as preclinical or inferred.
What It’s Used For
Ranked by how well the evidence holds up — which here means ranking things that are all preclinical:
- Memory and cognition in cholinergic deficit — the core evidence, entirely from lesioned rodents.
- Depression — one completed Phase 2 trial in 115 adults whose results were never published.
- Schizophrenia-related cognition — a single rat study with no follow-up.
Be sceptical of two claims in particular. Memory enhancement in healthy people has zero citable human data, and the animal work actively cuts against it — early studies found no benefit in normal animals, only in cholinergically damaged ones. And the widely repeated “enhanced” or “vivid” vision effect rests entirely on user anecdote; there is no study of it at all, in any species.
If the underlying goal is supporting the cholinergic system, dietary choline has an actual Adequate Intake and a real evidence base — which coluracetam does not.
How It Works
Making acetylcholine starts with getting choline into the neuron, and that transport step — not the enzymes that follow — is the rate-limiting one. Coluracetam acts precisely there: it enhances high-affinity choline uptake (HACU) by increasing the Vmax of the transporter and the density of CHT1 at the synaptic membrane, apparently by promoting transporter trafficking to the cell surface 6Reference 6MKC-231, a choline uptake enhancer: (3) mode of action of MKC-231 in the enhancement of high-affinity choline uptake — mechanistic studyView study →. In lesioned hippocampus this restores both acetylcholine synthesis and potassium-evoked release 4Reference 4AnimalMKC-231, a choline uptake enhancer: (2) effect on synthesis and release of acetylcholine in AF64A-treated rats — rat studyView study →.
What it does not do is inhibit acetylcholinesterase 2Reference 2AnimalEffect of the novel high affinity choline uptake enhancer MKC-231 on deficits of water maze learning in rats — rat studyView study →. That distinction matters — it is why, in animal comparisons, coluracetam produced its memory benefit without the tremor and salivation that came with tacrine.
The strangest finding is a timing one. In rats, the cognitive improvement and the raised choline uptake persisted at least 24 hours after the drug had cleared the brain 5Reference 5AnimalMKC-231, a choline-uptake enhancer: (1) long-lasting cognitive improvement after repeated administration in AF64A-treated rats — rat studyView study →. The effect tracks a lasting change in transporter regulation rather than ongoing drug exposure, which means the usual intuition — that effect follows blood level — does not apply here.
Pharmacology & Research
Coluracetam (originally MKC-231, later BCI-540) is a synthetic racetam and high-affinity choline-uptake enhancer — a mechanistically distinctive nootropic that acts on the choline transporter CHT1 rather than on acetylcholinesterase. Its reputation rests almost entirely on rodent work from the 1990s and 2000s showing it can rescue memory in animals with chemically induced cholinergic damage; that preclinical signal is genuine and reasonably well replicated. The human story, however, is close to empty: the only registered clinical trial (a Phase 2 study in major depression) was completed but never published with results, and no peer-reviewed human efficacy trial for cognition, mood, or the widely marketed “vivid vision” effect exists. Because coluracetam is sold as a research chemical of unverified purity and its human pharmacokinetics, toxicology, and long-term safety are uncharacterised, every claim below should be read as preclinical or inferred, not established in people.
Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric. Each application links down to its write-up.
Coluracetam’s core evidence comes from rats and mice given AF64A, a toxin that damages cholinergic neurons and models the cholinergic hypofunction seen in Alzheimer’s disease. Repeated oral dosing (0.3–10 mg/kg) reversed working-memory and water-maze learning deficits in these lesioned animals, whereas the acetylcholinesterase inhibitor tacrine did not, and did so without the tremor/salivation side effects of tacrine 1,
Notably the memory benefit was long-lasting — improvement persisted 24 h after the compound had cleared the brain, tracking a sustained rise in high-affinity choline uptake rather than drug levels 5Reference 5AnimalMKC-231, a choline-uptake enhancer: (1) long-lasting cognitive improvement after repeated administration in AF64A-treated rats — rat studyView study →.
All of this is animal data in an artificial deficit model; there is no human cognition trial, and no evidence of benefit in intact, non-deficient brains.
Gap: every positive result is in chemically lesioned rodents — nothing shows it improves memory in healthy humans, and early work found no acute benefit even in animals.
BrainCells Inc. (which licensed the compound from Mitsubishi Tanabe) ran a 6-week randomised, double-blind, placebo-controlled Phase 2 trial of BCI-540 at 80 mg once daily and 80 mg three times daily in 115 adults with major depressive disorder and concomitant anxiety, with co-primary endpoints on the IDS-C30 depression scale and the HAM-A anxiety scale 7Reference 7RCTBrainCells Inc. (2008–2009). A 6-week randomised double-blind, placebo-controlled study of BCI-540 80 mg q.d. and 80 mg t.i.d. in the treatment of adults with major depressive disorder and concomitant anxiety — Phase 2 RCT (completed, results not posted). ClinicalTrials.gov NCT00621270. https://clinicaltrials.gov/study/NCT00621270View study →. The trial is listed as completed (2008–2009) but no results were ever posted or published in the peer-reviewed literature, and the program was subsequently discontinued. The mechanistic rationale (choline-uptake enhancement and reported neurogenic effects) is plausible, but with no published efficacy data this cannot be treated as supportive.
Gap: a completed trial with unpublished results and a discontinued program is, at best, an absence of positive evidence — quite possibly a null that was never reported.
Mechanisms
| Target / pathway | Effect | Relevant to |
|---|---|---|
| High-affinity choline transporter (CHT1) | Enhances choline uptake; increases Vmax of HACU and transporter density at the synaptic membrane by promoting CHT1 trafficking 6Reference 6MKC-231, a choline uptake enhancer: (3) mode of action of MKC-231 in the enhancement of high-affinity choline uptake — mechanistic studyView study → | Memorycognition |
| Acetylcholine synthesis & release | Restores ACh synthesis and K⁺-evoked release in lesioned hippocampus (HACU is the rate-limiting step) 4Reference 4AnimalMKC-231, a choline uptake enhancer: (2) effect on synthesis and release of acetylcholine in AF64A-treated rats — rat studyView study → | Memorycognition |
| Acetylcholinesterase | No inhibition — distinct from tacrine/donepezil 2Reference 2AnimalEffect of the novel high affinity choline uptake enhancer MKC-231 on deficits of water maze learning in rats — rat studyView study → | Explains cleaner side-effect profile in animals |
| Glutamate excitotoxicity | Reduced Ca²⁺-influx–triggered (ionomycin) cytotoxicity in cultured cortical neurons in vitro; no effect on NO-donor toxicity 8Reference 8In vitroProtective effect of MKC-231, a novel high affinity choline uptake enhancer, on glutamate cytotoxicity in cultured cortical neurons — in vitro studyView study → | Neuroprotection (in vitro only) |
Pharmacokinetics
Human pharmacokinetics are not well characterised in the published literature. A striking preclinical feature is that the procognitive effect and the rise in choline uptake outlast measurable brain concentrations of the drug by ≥24 h, implying the effect is mediated by a lasting change in choline-transporter regulation rather than by ongoing drug exposure 5Reference 5AnimalMKC-231, a choline-uptake enhancer: (1) long-lasting cognitive improvement after repeated administration in AF64A-treated rats — rat studyView study →. Coluracetam is lipophilic and is used orally/sublingually by consumers, but a reliable human half-life, oral bioavailability, and metabolism profile are not established in citable sources; commonly repeated figures (e.g. a ~3 h half-life) trace to industry material rather than peer-reviewed data. Purity of consumer “research chemical” product is unverified.
Clinical trials
Registered human trial activity is minimal: one completed Phase 2 study in major depression (no results published), and no registered cognition trials. The compound is effectively an abandoned pharmaceutical asset with no active industry development.
| Completed | Planned | Terminated | Preclinical |
|---|---|---|---|
| 1(Phase 2, MDD; unpublished) | 0 | 0 | ~11 |
Last checked: August 2026.
Dietary Sources
Coluracetam does not occur in food. It is a wholly synthetic compound (a 2-oxopyrrolidine acetamide fused to a tetrahydrofuroquinoline, C₁₉H₂₃N₃O₃, MW 341.4), first synthesised by Mitsubishi Tanabe Pharma in the early 1990s as drug candidate MKC-231. There is no dietary intake and no natural repletion to correct — every dose is exogenous exposure to a research chemical.
If the goal is simply to support the cholinergic system, dietary choline — eggs, liver, soy, cruciferous vegetables — has an actual Adequate Intake and a real evidence base, unlike coluracetam. See choline.
Dosage
There is no validated human dosing regimen for coluracetam, and no RDA/AI or Tolerable Upper Intake Level exists — it is not a nutrient.
The only human doses on record come from the discontinued Phase 2 depression trial, which tested BCI-540 at 80 mg once daily and 80 mg three times daily 7Reference 7RCTBrainCells Inc. (2008–2009). A 6-week randomised double-blind, placebo-controlled study of BCI-540 80 mg q.d. and 80 mg t.i.d. in the treatment of adults with major depressive disorder and concomitant anxiety — Phase 2 RCT (completed, results not posted). ClinicalTrials.gov NCT00621270. https://clinicaltrials.gov/study/NCT00621270View study →. That study addressed depression, with no published outcome, so even this figure cannot be read as an effective — or safe — nootropic dose.
Widely circulated community protocols (roughly 5–35 mg taken sublingually, often with a choline source) are not backed by any clinical trial. They are recorded here only so the gap is visible: stating them as guidance would imply an evidence base that does not exist. These figures reflect what appears in research and registries, not a personal recommendation — and for coluracetam that research does not establish an effective or safe human dose at all.
Safety
Coluracetam’s human safety profile is essentially uncharacterised — and that is a statement about missing study, not about a clean record.
- A research chemical, not an approved medicine or supplement. Product purity and identity are unverified — a real risk independent of the molecule itself.
- No human safety study exists. No adverse-effect spectrum, no dose-limiting toxicity, no long-term data.
- Interactions are untested. A cholinergic mechanism could in principle interact with cholinergic or anticholinergic drugs; nobody has checked.
- Animal comparisons looked cleaner than tacrine (no tremor or salivation at effective doses) 2Reference 2AnimalEffect of the novel high affinity choline uptake enhancer MKC-231 on deficits of water maze learning in rats — rat studyView study → — but an animal comparison is not a human safety claim.
- No upper limit is set. Not a dietary nutrient; the absence of a limit implies nothing about what dose is safe.
Full Safety & Interactions Detail
No peer-reviewed human safety study defines coluracetam’s adverse-effect spectrum, no dose-limiting toxicity is established, and no drug-interaction data exist beyond the theoretical. Its cholinergic mechanism could plausibly interact with other cholinergic or anticholinergic drugs, but this is untested in people.
It is sold as a research chemical, so product purity and identity are unverified — an additional, real risk independent of the molecule itself. Animal studies reported a cleaner profile than the AChE inhibitor tacrine (no tremor or salivation at effective doses) 2Reference 2AnimalEffect of the novel high affinity choline uptake enhancer MKC-231 on deficits of water maze learning in rats — rat studyView study →, but that does not translate to a human safety claim.
Scope disclosure. Interactions assessed? No published human data — only a theoretical cholinergic-overlap caution can be stated. Pregnancy/lactation assessed? No — no reproductive safety data located, in humans or in the published animal literature. Upper limit established? No. Absence of reported harms here reflects absence of study, not evidence of safety.
Avoid. There are no reproductive or developmental safety data of any kind in humans or, in the published literature, in animals. With no data and research-chemical status, coluracetam should not be used during pregnancy or breastfeeding.
Related racetams: piracetam, aniracetam, oxiracetam, pramiracetam, phenylpiracetam, nefiracetam and fasoracetam. Mechanistically the relevant partner is choline itself — the substrate whose transport coluracetam is claimed to enhance — and choline donors such as citicoline.
References
- Murai S, Saito H, Masuda Y, et al. (1994). MKC-231, a choline uptake enhancer, ameliorates working memory deficits and decreased hippocampal acetylcholine induced by ethylcholine aziridinium ion in mice — mouse study. Journal of Neural Transmission (General Section), 98(1):1–13. https://pubmed.ncbi.nlm.nih.gov/7710736/
- Bessho T, Takashina K, Tabata R, et al. (1996). Effect of the novel high affinity choline uptake enhancer MKC-231 on deficits of water maze learning in rats — rat study. Arzneimittelforschung, 46(4):352–357. https://pubmed.ncbi.nlm.nih.gov/8740080/
- Shirayama Y, Yamamoto A, Nishimura T, et al. (2007). Subsequent exposure to the choline uptake enhancer MKC-231 antagonizes phencyclidine-induced behavioral deficits and reduction in septal cholinergic neurons in rats — rat study. European Neuropsychopharmacology, 17(9):605–614. https://pubmed.ncbi.nlm.nih.gov/17467960/
- Takashina K, Bessho T, Mori R, et al. (2008). MKC-231, a choline uptake enhancer: (2) effect on synthesis and release of acetylcholine in AF64A-treated rats — rat study. Journal of Neural Transmission, 115(7):1027–1035. https://pubmed.ncbi.nlm.nih.gov/18446264/
- Takashina K, et al. (2008). MKC-231, a choline-uptake enhancer: (1) long-lasting cognitive improvement after repeated administration in AF64A-treated rats — rat study. Journal of Neural Transmission, 115(7):1037–1046. https://pubmed.ncbi.nlm.nih.gov/18461272/
- Takashina K, et al. (2008). MKC-231, a choline uptake enhancer: (3) mode of action of MKC-231 in the enhancement of high-affinity choline uptake — mechanistic study. Journal of Neural Transmission, 115(7):1047–1054. https://pubmed.ncbi.nlm.nih.gov/18461273/
- BrainCells Inc. (2008–2009). A 6-week randomised double-blind, placebo-controlled study of BCI-540 80 mg q.d. and 80 mg t.i.d. in the treatment of adults with major depressive disorder and concomitant anxiety — Phase 2 RCT (completed, results not posted). ClinicalTrials.gov NCT00621270. https://clinicaltrials.gov/study/NCT00621270
- Akaike A, Maeda T, Kaneko S, et al. (1998). Protective effect of MKC-231, a novel high affinity choline uptake enhancer, on glutamate cytotoxicity in cultured cortical neurons — in vitro study. Japanese Journal of Pharmacology, 76(2):189–195. https://pubmed.ncbi.nlm.nih.gov/9541286/
For half-lives, timing and stacking across the nootropics on this site, see the Nootropic Dosage Guide.
