Radix Peptides
Research Monograph Series

Compound Monograph  ·  No. 24  ·  Research Use Only

5-amino-1MQ A methyl group, a metabolic thermostat, and the small molecule built to jam it

In 2014 a Harvard laboratory went looking for whatever gene swung hardest when fat cells were made insulin-sensitive or insulin-resistant. The answer was an enzyme almost nobody had been thinking about, whose only job is to stick a single methyl group onto vitamin B3. Silence it, and mice on a fattening diet stopped getting fat. Three years later a laboratory in Galveston screened its way to a small molecule that blocks the same enzyme, and gave it to obese mice: they lost weight without eating less. That compound is 5-amino-1MQ. It is not a peptide, although it is sold almost exclusively by peptide vendors. It has never been given to a human being in any published or registered study. It is swallowed as capsules by people who found it online, by a route that delivered three and a half per cent of the dose in the only species where anyone has measured it. In January 2026 the United States Food and Drug Administration named it in a warning letter. The target is real and interesting; this document is about the distance between that and the compound.

Compiled by South Beach Longevity · 2 August 2026
Copyright 2026
Corpus 27 scientific full texts · ~495 printed-page equivalents
Metadata layer 184 PubMed records screened from 188
Source project 05 · Therapeutic Peptide Research Library
Constraint No human use, dose, route or schedule is recommended anywhere in this document

01A small molecule in a peptide market

Almost everything sold in the research-chemical peptide market really is a peptide: a chain of amino acids linked by amide bonds, made on a solid-phase synthesiser, shipped as a lyophilised powder in a glass vial. 5-amino-1MQ is none of those things. It is a single fused aromatic ring system with a methyl group on its nitrogen — the kind of molecule a medicinal chemist would call a small-molecule heterocycle, and the kind of thing that turns up in a high-throughput screening library rather than in a peptide catalogue. It contains no amino acids, no peptide bond, and nothing that could be described as a chain.

This is not a quibble about vocabulary. Consider the description that a major vendor gave the compound on its own product page, archived in this project's library in January 2024: “5-amino-1MQ (5-amino-1methylquinolinium) an analogue of methylquinolinium, is a short peptide inhibitor of cytosolic nicotinamide N-methyltransferase.” A companion product page, selling 5-amino-1MQ together with nicotinamide mononucleotide and a second NNMT inhibitor, opens by describing all three as peptides. Nicotinamide mononucleotide is a nucleotide. The second inhibitor is a pyridine carboxamide. Neither is a peptide either.

Calling a quaternary ammonium cation a peptide imports a set of assumptions that do not hold. Peptides are, broadly, degraded by peptidases, cleared quickly, poorly absorbed from the gut for reasons of size and enzymatic lability, and — as a class — carry a reasonably well-understood regulatory position. A small permanently charged heterocycle has a different absorption problem, a different metabolic fate, a different distribution, and, as Section 23 sets out, a quite specific and unfavourable regulatory position of its own. The misclassification also travels into the practical: the same vendor page prints the molecular formula and mass of the free cation directly beside the registry number of the iodide salt, two facts about two different substances, presented as though they described one.

02Seven names for one molecule

A compound's name is its retrieval key. If a reader cannot find the literature, the literature might as well not exist; if a matcher cannot find it, a corpus is built on sand. 5-amino-1MQ has no settled name, and the variants in active use in peer-reviewed papers are these:

The last row is the one that matters. Read literally, 5MQ is 5-methylquinolinium — the 5-methyl analogue, a real and different substance with no amino group at all. Two papers nonetheless use it to mean 5-amino-1-methylquinolinium, and one of them contradicts itself while doing so. Akar and colleagues, reporting antiproliferative activity in cervical cancer cells, write in their abstract that the anti-proliferative effects “of 5-methylquinolinium (5MQ)” had not previously been tested; their keyword list and their own impact statement give the compound as 5-amino-1-methylquinolinium. The paper does not say which molecule was in the flask. Campagna and colleagues, studying the enzyme in endothelium, write “5-amino-1-methylquinoline – 5MQ”, which keeps the amino group and drops the quaternary nitrogen.

Neither is a scandal; both are ordinary slips of the kind that occur when a compound circulates faster than its nomenclature settles. But the consequences are real and they compound. A reader searching for “5-amino-1MQ” will not find the Akar paper. A reader searching for “5MQ” will find papers about several unrelated things. A supplier writing a certificate of analysis from a literature summary has seven strings to choose from and no authority to choose between them. And a reader trying to establish what has actually been demonstrated about this molecule has to reconcile a body of work that does not agree on what to call its own subject.

03What it is made of, and why the dose is ambiguous

The molecule is a quinoline — a benzene ring fused to a pyridine ring — carrying a methyl group on the ring nitrogen and a primary amine at position 5 of the carbocyclic ring. Because the nitrogen carries four bonds it holds a permanent positive charge, at every pH the body can produce. There is no neutral form of this substance and there is no pH at which it becomes uncharged. That single fact shapes almost everything that follows: how it crosses membranes, how it is excreted, and why it resembles the product of the reaction it blocks.

The cation is C₁₀H₁₁N₂⁺, formula weight 159.21, registered as CAS 685079-15-6. It is supplied as a salt, and which salt matters:

A quantity of the iodide salt contains 1.8 times less active substance than the same quantity of the cation. Fifty milligrams of iodide is 27.8 mg of 5-amino-1MQ; fifty milligrams of the chloride is 40.9 mg. A figure quoted without naming the salt is therefore ambiguous by nearly a factor of two, and vendor material routinely quotes such figures.

The primary literature is careful about this in a way the market is not, and the care is worth noticing because it is a useful check on the arithmetic. The first in-vivo study dosed mice at 20 mg/kg per injection, three times a day, which is 60 mg/kg of material per day — and reported the dose as “approximately 34 mg/kg/day of the parent compound, calculated according to free weight”. Sixty multiplied by 159.21/286.11 is 33.4. The authors were dosing the iodide and reporting the cation. A later study from the same programme states its dose as “32 mg/kg of active pharmaceutical ingredient” delivered as 4 mg/mL of the monochloride salt at 10 mL/kg — that is, 40 mg/kg of salt reported as 32 mg/kg of substance, which is the chloride's own conversion factor. Two conventions, two salts, both handled correctly, and neither obvious from the number alone.

An independent confirmation of the identity comes from an unexpected direction. The rat pharmacokinetic assay published in 2021 quantified the compound by tandem mass spectrometry on the transition m/z 159.100 → 90.00. The precursor mass of 159.1 is the cation and nothing else — not the iodide, not a hydrate, not a metabolite. Whatever was in that laboratory's vials, the species it measured in plasma was the one this section describes.

04One reaction, two currencies

Nicotinamide N-methyltransferase does one thing. It takes a methyl group from S-adenosyl-L-methionine and attaches it to the ring nitrogen of nicotinamide — vitamin B3 — producing 1-methylnicotinamide and S-adenosyl-L-homocysteine. It is a cytosolic, single-chain enzyme of 264 amino acids and 29.6 kDa, encoded on human chromosome 11q23.1, carrying enzyme classification EC 2.1.1.1 (Roberti et al., 2021).

The transfer is direct and in-line: the crystal structure of the human ternary complex places the acceptor nitrogen 3.5 to 4.2 Å from the sulfur of the demethylated cofactor, a distance consistent with a linear transition state and slightly longer than the two single bonds that form and break. Mutating tyrosine 20 to alanine leaves 0.6 per cent of wild-type activity, and aspartate 197 to alanine 2.4 per cent, in both cases by wrecking cofactor affinity rather than catalysis — the Michaelis constant for the methyl donor rises 690-fold and 546-fold respectively while turnover number falls only about twofold. The two serines that hydrogen-bond the substrate's amide can each be removed with almost no effect.

What makes the reaction interesting is not its chemistry but its accounting. Each turnover spends one molecule from each of two pools the cell cannot easily refill.

The first is nicotinamide. More than eighty-five per cent of mammalian NAD⁺ is made not from scratch but by salvage, recycling nicotinamide released when NAD⁺-consuming enzymes do their work. Methylation takes a nicotinamide molecule out of that loop permanently: 1-methylnicotinamide cannot be salvaged, and NNMT is the only catabolic enzyme mammals have for nicotinamide. In adipose tissue this matters most, because fat has no alternative route — only liver and kidney can build NAD⁺ from tryptophan.

The second is S-adenosylmethionine, the universal methyl donor for DNA methylation, histone methylation, polyamine synthesis and a few hundred other transfers. Spending it produces S-adenosylhomocysteine, which inhibits methyltransferases generally, so the reaction taxes the cell's methylation capacity twice over. Here the tissue asymmetry runs the other way: in liver, glycine N-methyltransferase dominates transmethylation flux and buffers NNMT's contribution, whereas in adipose tissue NNMT is itself a major methyltransferase and its expression tracks with methyl-donor balance and histone methylation (Roberti et al., 2021).

The objection that will not go away

The elegance of the two-currency argument has a kinetic problem, and it is raised in this literature by researchers who are otherwise sympathetic to the target. The Michaelis constant of NNMT for nicotinamide is not settled — reported values in the corpus span 7 µM to 400 µM depending on the assay, and one direct binding measurement by nuclear magnetic resonance puts the dissociation constant above 5 mM. Take even the middle of that range and NNMT is a low-affinity enzyme for its own substrate. The salvage enzyme it is supposed to be competing with, nicotinamide phosphoribosyltransferase, operates in the low nanomolar range.

Two independent groups say plainly that this makes the depletion story hard to credit. Reviewing their own cardiac data, one team notes that NNMT's affinity is “several orders of magnitude lower” than the salvage enzyme's, so that recycling “may predominate over” methylation, and calls their own finding unexpected for that reason. The team that developed a rival inhibitor calls the NAD⁺-depletion mechanism “unlikely because of the high Km value of NNMT for nicotinamide compared to NAMPT” (Kannt et al., 2018). A 2024 review of the target's metabolic case goes further, observing that murine knockdown produced neither nicotinamide accumulation nor a significant change in hepatocyte NAD⁺, and concluding that NNMT may regulate energy metabolism by some other route altogether.

The figures below present the range rather than a single number, because averaging assays that differ by two orders of magnitude would manufacture a precision the field does not have.

05The knockdown that started it

The modern interest in this enzyme has a specific origin, and it was not a search for a weight-loss drug. In 2014 Daniel Kraus, Qin Yang, Barbara Kahn and colleagues at Beth Israel Deaconess Medical Center and Harvard were studying the glucose transporter GLUT4 in fat. They had two mouse lines — one with GLUT4 deleted from adipose tissue, one with it overexpressed — and they ran microarrays on white adipose tissue from both, asking which genes moved most in opposite directions. The answer, reported in Nature, was Nnmt: the most strongly reciprocally regulated gene in the comparison (Kraus et al., 2014).

They then knocked the enzyme down with antisense oligonucleotides in white adipose tissue and liver of mice fed a high-fat diet. The animals were protected against diet-induced obesity, with a 47 per cent reduction in relative fat mass, and the protection came from increased energy expenditure rather than from eating less. Adipose S-adenosylmethionine and NAD⁺ both rose.

The mechanistic chain they proposed is more specific than the two-currency story and considerably better evidenced. Raising the methyl-donor pool altered histone H3 lysine 4 methylation at the promoters of two enzymes of polyamine metabolism — ornithine decarboxylase and spermidine–spermine N¹-acetyltransferase — raising their expression and activity. Polyamine synthesis and catabolism together form a futile cycle: making them consumes decarboxylated S-adenosylmethionine, acetylating them consumes acetyl-CoA, and the cycle turns without net product. Urinary and secreted diacetylspermine, a marker of that flux, rose. Critically, the increase in adipocyte oxygen consumption caused by NNMT inhibition was abolished when ornithine decarboxylase, the acetyltransferase, or polyamine oxidase were blocked in turn. The phenotype was mapped onto the pathway epistatically, not merely correlated with it.

06Where the enzyme is, and when it rises

NNMT is a liver enzyme first. Human hepatic activity has been measured at 51 nanomoles of methyl-nicotinamide formed per hour per milligram of liver protein; the mouse figure is 16, about one third. It is present at intermediate levels in adipose tissue, skeletal muscle, kidney, lung, heart and several female reproductive tissues, and at low levels in brain, although two reviews in this corpus disagree about the brain in terms that cannot both be right — one calls expression there “very low”, the other calls it neuron-exclusive with regional variation.

Between individuals, human liver activity varies about fivefold, and the distribution is bimodal — a pattern that usually indicates a common genetic variant, though none has been definitively identified. Human genetics otherwise supports NNMT as a determinant of plasma homocysteine, which a family-based linkage study in Spain identified as its principal genetic determinant. The candidate-gene associations with obesity, hyperlipidaemia, type 2 diabetes and hypertension come almost entirely from two populations, have not been independently replicated, and no genome-wide significant signal at the locus appears anywhere in the corpus. No human loss-of-function data exists at all.

What makes the enzyme a target is that it rises in the diseases people want to treat, and falls when those diseases improve:

The correlations are consistent and, in the metabolic setting, bidirectional — the enzyme goes up with the disease and down with successful treatment of it, which is more than most biomarkers manage. What they do not establish is direction of causation, and the association literature should not be read as though they did. The causal evidence is the knockdown work of Section 05 and the pharmacology of Part Four.

07The product is not waste

1-methylnicotinamide is usually introduced as the reaction's disposal product: methylated, no longer salvageable, oxidised by aldehyde oxidase to N¹-methyl-2-pyridone-5-carboxamide in humans and its 4-pyridone isomer in rodents, and excreted. That framing is convenient for an inhibitor programme and it is not accurate. The product has a pharmacology of its own, and blocking the enzyme removes it.

It is antithrombotic, and the mechanism has been mapped. In rats with extracorporeal thrombus formation, 1-methylnicotinamide at 3 to 100 mg/kg produced a dose-dependent, sustained thrombolytic response accompanied by a rise in the stable prostacyclin metabolite. The response was dose-dependently blocked by rofecoxib and abolished by indomethacin, and was unaffected by inhibiting nitric oxide synthase — a cyclooxygenase-2-dependent effect. The same doses reduced arterial thrombosis in hypertensive rats. In vitro the molecule neither aggregated platelets nor dilated vessels, so it is not acting directly on either; the authors proposed that endogenous 1-methylnicotinamide, made in the liver by NNMT, is a physiological activator of prostacyclin production.

It is vasoprotective and antioxidant. It enhances endothelial nitric oxide production and improves endothelial function in hypercholesterolaemic mice; it activates NRF2 and suppresses NF-κB signalling, upregulating NAD(P)H quinone oxidoreductase 1, haem oxygenase-1 and glutamate–cysteine ligase in cardiomyocytes exposed to palmitate and in high-fat-fed mice. In atherosclerotic mice, 1-methylnicotinamide reduced plaque size and macrophage infiltration more effectively than nicotinamide itself.

It is hepatoprotective. Exogenous 1-methylnicotinamide prevents concanavalin-A-induced hepatitis in mice, and the protection is lost when the prostacyclin receptor is blocked.

And it restrains its own enzyme. 1-methylnicotinamide binds the enzyme–cofactor-product complex with a dissociation constant of about 80 nanomolar by surface plasmon resonance, independently confirmed by calorimetry (Akerud et al., 2025). The authors draw the obvious conclusion: “there should be substantial product inhibition unless the 1-MNA levels are kept low in vivo”. The enzyme is braked by what it makes.

None of which makes the molecule an unqualified good. Given to leptin-receptor-deficient mice at 100 mg/kg for four weeks it changed neither fasting glucose nor glycated haemoglobin, and body weight tended to rise. Supplementation worsened hepatic lipid accumulation in alcohol-fed mice. And its downstream oxidation products carry a human signal in the opposite direction: across two cohorts totalling 3,163 people, high circulating levels of the two pyridone metabolites were associated with increased risk of major adverse cardiovascular events — which is, in fact, the best human argument anywhere in this corpus for reducing flux through this enzyme.

The honest summary is that the reaction produces a signalling molecule with a mixed portfolio, that an inhibitor necessarily lowers it, and that no study in this corpus has measured what lowering it does in an animal over a long enough period to matter.

08A screen, a scaffold, and compound 1j

The compound came out of a collaboration between two Texas laboratories: Stanley Watowich's biochemistry group at the University of Texas Medical Branch in Galveston, and Stanton McHardy's medicinal chemistry group at the Center for Innovative Drug Discovery at the University of Texas at San Antonio. Harshini Neelakantan, then a pharmacologist at Galveston whose previous publications were on serotonin receptor agonists and opioid self-administration, is the first author of the chemistry paper and of the two in-vivo studies that followed.

Their route to a molecule was unglamorous and effective. Before they could screen anything they needed an assay: existing NNMT assays were coupled, slow and awkward, so in early 2017 the group published a non-coupled fluorescent method that watches the reaction directly and in real time (Neelakantan et al., 2017). With that in hand they screened N-methylated quinolinium, isoquinolinium, pyridinium and benzimidazolium analogues — small, flat, positively charged heterocycles chosen to resemble the molecule the enzyme already accepts — and reported inhibitors spanning more than a thousandfold in activity. The quinoliniums came out best, at around one micromolar. Docking the series into the substrate pocket of the published human structure produced a robust correlation between predicted interaction score and measured potency, which is the kind of result that lets a chemistry programme prioritise the next round of compounds with some confidence.

Within the series, one analogue carried a primary amine at position 5 of the carbocyclic ring, and it was the best of them. In the patent that the University of Texas System filed on 29 March 2018, claiming priority to 30 March 2017, it is compound 1j, and its half-maximal inhibitory concentration against the human enzyme is given as 1.2 µM. That is 5-amino-1MQ. The patent issued on 2 August 2022 as US 11,401,243, with Watowich, Neelakantan, Hua-Yu Wang and McHardy as inventors; a continuation issued in August 2024 extending the claimed uses to obesity, metabolic disorders, NNMT-expressing cancers including glioblastoma, Parkinson's disease, modulation of stem-cell differentiation, and muscular dystrophy.

The name is worth pausing on. “1j” is a compound number in a table, the tenth entry in a synthetic series. It was never christened, never given an INN, never assigned a development code by a company. It reached the consumer market under the string a chemist would write on a vial.

09How it binds

5-amino-1MQ occupies the nicotinamide site — the pocket where the methyl acceptor binds — and blocks the transfer by being in the way. It is not an allosteric inhibitor, and it is not a bisubstrate inhibitor reaching across both pockets; two independent papers describe it as a substrate-site, product-mimicking competitor.

The pocket rewards exactly what a quinolinium offers. The ligand ring stacks in a hydrophobic clamp between tyrosine 204 on a β-hairpin lid and leucine 164 in the central domain. Tyrosine 20 sits at the mouth of the methyl-transfer tunnel and hydrogen-bonds ring substituents at the corresponding position, which is the most plausible role for the 5-amino group, and the tunnel itself is a narrow linear channel of three and a half to four Ångströms.

Why the quaternary methyl helps has a good answer, though it comes from work on a different chemotype. Comparing thirteen matched pairs of neutral nicotinamide analogues and their methylated cations, one group found the cations bind the enzyme–product complex on average 3.5 log units — about three thousandfold — more tightly than the neutral parents bind the enzyme–cofactor complex, with association about elevenfold faster and dissociation more than three hundredfold slower. They attribute the difference to electrostatic complementarity with the post-catalytic state, and note in passing that the enzyme–product complex is intrinsically the most ligandable form of the protein (Akerud et al., 2025). A permanent positive charge is not incidental decoration on this scaffold; it is the reason a flat aromatic can bind an enzyme that evolved to bind a cation.

10The permeability paradox

A permanently charged molecule should not cross a lipid membrane. The 2018 paper reports that this one does: in a parallel artificial-membrane assay, 5-amino-1MQ and its 7-amino isomer showed high passive permeability and active transport, with no detectable efflux in a Caco-2 monolayer, while the unsubstituted parent 1MQ and the reaction product 1-methylnicotinamide showed no passive permeability at all. The authors took this as evidence of likely high oral absorption and bioavailability.

That inference did not survive measurement, and Section 19 gives the number. But it is worth setting the in-vitro claim against what the wider literature says about charged NNMT ligands, because the pattern is consistent and it runs the other way. Across the matched neutral-and-cation series described above, the cations were on average fortyfold less potent in cells than against the purified enzyme, while their neutral parents were, if anything, slightly more potent in cells. 1-methylnicotinamide itself is inactive in cells below 30 µM. The whole design strategy of that programme — dose the neutral precursor and let the enzyme make the cation inside its own active site — exists because charged NNMT ligands do not readily get into cells.

The only cell-based work with 5-amino-1MQ itself points the same way. The 2025 study that reports the compound's potency value also ran it against four tumour cell lines, and required 100 µM — about eighty times its enzyme-level potency — to suppress product formation by half. At 10 µM, effects were absent in most lines at most time points. That eighty-fold gap is the honest measure of what the molecule does inside a cell, and it is roughly what a permanent cation would predict.

11Where it ranks

Judged as a molecule rather than as a story, 5-amino-1MQ is a first-generation tool compound and the field has moved past it. The comparison has to be made carefully, because potency values for this target come from at least five mutually incompatible assay systems — one shared compound, the bisubstrate control MS2756, differs elevenfold between two of them — so the figure below groups values by assay rather than pooling them.

Three anchors give the shape of it. Against the same purified human enzyme, the best small molecule from the Sanofi tricyclic programme is 33 nanomolar, roughly thirty-five times more potent. The bisubstrate inhibitors, which reach across both pockets at once, run from 1.6 nanomolar down to 500 picomolar — three orders of magnitude below 5-amino-1MQ, though measured differently again. And the field's own summary of itself, written in 2025, is that most NNMT inhibitors “display high nanomolar to low micromolar inhibitory effects in enzymatic assays but only a few show potent cellular inhibition”. At 1.2 µM, this compound sits at the weak end of that band, and it has been described in the same terms — “modest activity at µM levels”, “inhibiting NNMT at micromolar levels” — in 2019, in 2024 and in 2025. Nobody upgraded it.

Potency, though, is not why it matters. Of every NNMT inhibitor in this corpus, only three have ever been given to an animal: 5-amino-1MQ, and the two Sanofi compounds. No bisubstrate inhibitor has ever been dosed in vivo — a point the field has been making about itself since 2022 and which remains true through the most recent papers here. The molecule earned its place in the literature by being available, soluble, and good enough to test a hypothesis in a mouse, not by being the best inhibitor anyone had made.

The rivals, and what they showed that this compound did not

Two comparisons deserve to be drawn out, because both bear directly on how much confidence the 5-amino-1MQ animal data can carry.

The knockout control. When Kannt and colleagues tested their 6-methoxynicotinamide compound JBSNF-000088 in mice lacking NNMT entirely, it produced no metabolic benefit — exactly as it should if the drug works through the enzyme. That is a clean attribution. When the same programme later tested its more potent tricyclic successor JBSNF-000028 the same way, glucose tolerance improved and insulin fell in the knockout animals too, pointing to an effect beyond NNMT inhibition. The authors nominated their own compound's 90 per cent inhibition of monoamine oxidase A as the likely confound (Ruf et al., 2022). Two compounds from one laboratory, one clean and one not. No knockout control has ever been run for 5-amino-1MQ.

The models where it failed. Both Sanofi compounds produced clear metabolic benefit in diet-induced obese mice and then failed almost completely in leptin-deficient ob/ob and leptin-receptor-deficient db/db mice, where the only surviving effect was suppression of the reaction product. The authors attribute this to hyperphagia the compounds are not strong enough to override. 5-amino-1MQ has never been tested in either model, so its diet-induced-obesity result cannot be assumed to generalise — and the failure mode is already documented, twice, for structurally unrelated inhibitors of the same enzyme.

One further finding from the rival programmes belongs here because it is a criticism of the mechanism rather than of any molecule. The nicotinamide-analogue inhibitors are not classical blockers; they are slow substrates that the enzyme turns over. That means they keep consuming S-adenosylmethionine while they act. Measured in rats, the first-generation compound drove S-adenosylmethionine consumption to 470 per cent of baseline during maximal inhibition — a futile methyl sink several times larger than the natural substrate's. Whether this applies to a quaternised quinolinium, which has no free ring nitrogen to methylate, is not addressed anywhere in this corpus. It is a reasonable question and nobody has asked it in print.

12Five experiments, not six

Six papers report giving 5-amino-1MQ to mice for a metabolic or muscular purpose. They describe five experiments. The 2021 study of diet plus drug and the 2022 study of the caecal microbiome are the same animals: the second paper describes itself as a secondary-endpoint study on the same series of diets, correlates its results against the first paper's fat-pad metabolome, and reproduces its staggered two-day euthanasia schedule exactly. They are one cohort with two sets of readouts, and counting them as two independent confirmations overstates the record by twenty per cent.

All five used subcutaneous injection. Not one used the oral route. Every animal was a mouse. Five of the six papers used males only and the sixth used females only. The whole in-vivo programme traces to one laboratory at the University of Texas Medical Branch and its spin-out company, with a single exercise study run at the University of Kentucky.

13Obesity, 2018: the founding result

Neelakantan and colleagues took male C57Bl/6 mice that had been fed a 45-per-cent-fat diet for sixteen weeks and had reached about 38 g, and randomised eighteen of them, nine per group. The treated animals received three subcutaneous injections a day — at roughly half past nine, half past one and half past five — of 20 mg/kg per injection, reported as about 34 mg/kg/day of the cation. This continued for eleven days.

Over those eleven days the control animals gained 0.6 ± 0.4 g, about 1.4 per cent, and the treated animals lost 2.0 ± 0.6 g, about 5.1 per cent. Repeated-measures analysis gave a treatment effect at p = 0.0028 and an interaction with time at p < 0.0001, with the separation significant from day six. Epididymal white adipose tissue fell by about 35 per cent, and adipocyte cross-sectional area by more than 30 per cent. Plasma total cholesterol was about 30 per cent lower.

The control that matters is the one for food intake. Cumulative consumption was 28.1 ± 1.2 g in controls and 26.2 ± 1.4 g in treated animals, not significantly different. Weight was lost while the animals ate the same amount. That is what separates this mechanism from appetite suppression, and it is the single most important observation in the dataset. It is also what makes the compound interesting to a market saturated with incretin agonists that work precisely by making people eat less.

Three things about this study deserve to travel with it. The cholesterol comparison was made against values “reported by the vendor for age-matched mice” rather than a concurrent lean control group. Plasma triglycerides were measured and then discarded, because haemolysis interfered with the assay — so this study contributes no triglyceride data at all. And the dose was chosen on the basis of an escalation study in two animals, ranging from 10 to 150 mg/kg/day, of which the paper reports only that 60 mg/kg/day was well tolerated. Every dose used in the subsequent literature descends from that sentence.

14Obesity, 2024: a longer study, and a smaller effect

Six years later the same programme, now with a company affiliation, ran the study the first one had not. Eight mice per group, three groups, 10 or 32 mg/kg/day subcutaneously, once daily, for thirty days, with the efficacy work contracted to WuXi AppTec and the pharmacokinetics to XenoBiotic Laboratories.

The result is real and it is smaller than the headline usually suggests. High-dose animals gained 0.9 g against 5.4 g in controls and 5.2 g at the low dose — that is attenuation of weight gain, not weight loss. Fat mass rose 1.3 g against 4.7 g. Plasma insulin fell 9 per cent from baseline while rising 112 per cent in controls, and the effect survived adjustment for both terminal body weight and fat mass, which is a meaningful control. Glucose at fifteen and thirty minutes after an oral load was significantly lower. Liver weight averaged 1.4 g against 2.1 g; microvesicular steatosis fell 73 per cent; the NAFLD activity score, lobular inflammation, ballooning and macrophage marker all improved; alanine transaminase fell.

The low dose did essentially nothing on the primary endpoints. Fed-state blood glucose was unchanged throughout at either dose. Lean mass was unaffected. Serum lipids other than triglycerides moved only as non-significant trends, so the 30 per cent cholesterol reduction of 2018 was not reproduced here. And two markers — creatine kinase and lactate dehydrogenase — reached significance only at the low dose, which the paper does not reconcile.

Read across the whole record, the direction and size of the body-weight effect depend on the dose, the duration and what the animals were eating. Eleven days at roughly 34 mg/kg/day on a maintained high-fat diet produced a two-gram loss; thirty days at 32 mg/kg/day on a maintained high-fat diet produced a 0.9-gram gain; seven weeks at 32 mg/kg/day with a switch to a low-fat diet produced a 6.3-gram loss; eight weeks at 10 mg/kg/day in aged non-obese animals produced essentially nothing. There is no single number for what this compound does to body weight.

15Diet and drug together

The 2021 study asked a more useful question than either obesity study: what does the drug add to a dietary change someone is making anyway? Twenty-two diet-induced obese mice were switched from a Western diet to a low-fat diet and given either saline or the compound for about seven weeks, alongside eight lean controls.

Switching the diet alone produced an initial 4.3 g loss by day twenty, then a plateau and slight regain, ending at 2.9 g down. Adding the drug produced 6.3 g, and the treated animals ended the study “nearly indistinguishable” from lean controls on body weight and fat mass. In percentage terms the fat-mass loss was tenfold greater with the drug than with the diet switch alone — 29.3 per cent against 2.9 per cent. Liver fat and steatosis scores in the combined group matched the lean controls; the diet-switch-only group matched the obese controls.

The most interesting result in that paper is a negative one, and the authors report it plainly. They measured 170 metabolites in the fat pad expecting the treated animals' metabolome to shift from the obese profile toward the lean one. It did not. “Contrary to our expectations, NNMTi treatment did not simply shift the EWAT metabolomic profile from the obese state profile to the lean state profile, but instead produced a unique EWAT metabolomic signature.” The animals looked lean by every physiological measure and their fat tissue looked like neither obese nor lean tissue. Four essential amino acids and tyrosine rose well above both control groups; the nicotinamide-to-nicotinic-acid ratio rose, though only without correction for multiple comparisons; and for two metabolites the drug moved things away from the lean profile that the diet switch alone had approached.

16Muscle, twice

The muscle work is the strand that made the compound interesting to the longevity market, and it is two studies with different designs and partly divergent results.

2019, injury and regeneration. Forty-eight 24-month-old male mice received twice-daily subcutaneous injections at 5 or 10 mg/kg for two weeks, spanning a barium-chloride injury to one tibialis anterior. Muscle stem-cell proliferation rose 60 per cent at the low dose and 75 per cent at the high dose; mean myofibre cross-sectional area at one week was 1.8-fold larger at the high dose; and peak dorsiflexor torque normalised to body weight was 67 per cent higher.

Set against that: the total stem-cell pool was unchanged (209 ± 23, 213 ± 44 and 205 ± 9 cells per square millimetre across the three groups). Stem-cell fusion did not reach significance (p = 0.0686 at the top dose). The low dose failed on cross-sectional area entirely. Torque normalised to fibre size showed no difference — the muscle was bigger, not intrinsically stronger. And the three-week result depends on excluding one animal: the figure legend states that with that datapoint included the comparison is not significant.

2024, exercise. Thirty-five 22-month-old female mice received 10 mg/kg once daily for eight weeks, with or without progressive weighted wheel running. Grip strength rose about 40 per cent with the drug alone against about 20 per cent with exercise alone, and about 60 per cent with both — the finding that produced the headline that a drug outperformed exercise. Intramyocellular lipid fell more than 30 per cent in sedentary treated animals, to levels seen in exercised animals. Raw gastrocnemius mass rose.

And the qualifications are substantial. Grip strength normalised to body weight lost significance for the drug alone (p < 0.06), and the treated mice were about ten per cent heavier at baseline. Peak plantarflexor torque was not changed by the drug, by exercise, or by both — the endpoint that had improved 67 per cent in the 2019 study. Peak torque did not correlate with grip strength in any group. Fibre cross-sectional area was unchanged by the drug alone. Body-weight-normalised muscle masses were unaffected. And cumulative work during the fatigue task was significantly reduced in treated animals, which the authors attribute to lower per-contraction force. The sedentary groups were housed together and the exercised groups singly.

The two studies used different muscles, different sexes, different dosing frequencies and different injury states, so they are not a failed replication. But the plain reading is that a torque benefit is not a general property of this compound, and that the 2024 grip-strength result — the one that travelled — sits beside a measured decrement in sustained work output that did not.

17Elsewhere: tumours, kidneys, pancreas, gut

Outside metabolism and muscle, the compound has been used as a tool in five further in-vivo settings, and the pattern across them is consistent and important: where it works, it works on the tissue around the disease rather than on the diseased cells.

In ovarian cancer, 20 mg/kg intraperitoneally daily for ten days in nude mice reduced intraperitoneal tumour burden and raised histone H3K27 trimethylation in the stroma (Eckert et al., 2019). The same paper states that the inhibitor “did not affect the viability of CAFs or OvCa cells”, and that viability fell only at high concentrations. In bladder cancer, 10 mg/kg every twelve hours for nineteen days reduced tumour burden and shifted tumour-associated macrophages from an immunosuppressive to an inflammatory phenotype, with a clear trend toward added benefit alongside anti-PD-L1 antibody (Yang et al., 2024) — and in the same paper, overexpressing the enzyme in fibroblasts did not change their proliferation and did not directly affect the cancer cells.

In chronic pancreatitis, 20 mg/kg intraperitoneally daily for four weeks reduced fibrosis, collagen deposition and alternatively activated macrophages in a cerulein model, through a histone-methylation mechanism at a single gene promoter. In peripheral artery disease, the compound improved ischaemic muscle strength, power and total work without changing perfusion or capillary density (Dong et al., 2025) — and in the same experiment muscle mass and fibre size were unchanged and the reduction in necrosis reached only p = 0.08. In chronic kidney disease and in renal cell carcinoma the same catalogue compound reduced fibrosis and tumour growth respectively.

None of this is human evidence, and none of it is evidence that the molecule kills anything. The oncology results are real and they are microenvironmental. Presenting them to a consumer audience as anticancer activity would misdescribe what was measured.

18Mechanism: what is measured, and what is assumed

Almost every account of this compound — vendor pages, review articles, and the discussion sections of the primary papers themselves — explains it the same way: blocking the enzyme spares nicotinamide, nicotinamide is recycled into NAD⁺, NAD⁺ activates sirtuins, and the metabolic benefits follow. It is a clean story. Here is how much of it has been measured.

The honest position is that target engagement is well demonstrated and the downstream mechanism is largely inherited. The compound unquestionably lowers the reaction product in the tissues where it accumulates; that is measured directly, in three tissues, with a dose response. Everything after that step — the NAD⁺ rise, the sirtuin activation, the polyamine cycle, the increased energy expenditure — is either measured only in cells, or measured only for the genetic knockdown, or not measured at all. The mechanism is not wrong. It is, in this compound's own literature, substantially unverified.

19The oral question

5-amino-1MQ is sold, overwhelmingly, as capsules to be swallowed. The pharmacokinetics were published in 2024, and they are the most consequential numbers in this document.

Read the oral row against the subcutaneous row above it. A dose six times larger produced a peak concentration 484 times lower. The authors attribute this to limited absorption plus extensive first-pass metabolism, and they measured the second part: in cryopreserved mouse hepatocytes the compound has a half-life under seven minutes and a clearance of 57.9 mL/min/kg.

For target engagement the relevant threshold is the potency against the mouse enzyme, 78 ng/mL. After parenteral dosing, plasma stayed above it for two to four hours. After oral dosing the peak concentration — 14.5 ng/mL — never reached it at all.

Two qualifications are owed. The first is that the 2018 paper predicted the opposite. Its artificial-membrane and Caco-2 results led its authors to suggest “high oral absorption and bioavailability”, and that prediction is still quoted. It was tested six years later and it was wrong. The second is species. The 2022 microbiome paper states that poor oral bioavailability is a mouse phenomenon “that does not occur in rats”, and there is supporting evidence: the 2021 rat study reports 38.4 per cent oral bioavailability after an oral dose, with a mean peak plasma concentration of 2,252 ng/mL. Rat and mouse differ elevenfold, which is a large enough gap that neither number can be assumed to describe a person.

What can be said is narrower and firmer. No efficacy study of this compound has ever used the oral route in any species. Every result in Part Four came from an injection. Whether swallowing it produces useful exposure in a human being is unknown, unmeasured, and — on the only direct comparison available in the species where efficacy was demonstrated — unlikely.

The tissue distribution is more encouraging and worth stating. After five days of subcutaneous dosing, the ratio of drug concentration in epididymal fat to plasma rose from 1.4 at one hour to 31.1 at eight hours, and in muscle from 2.2 to 17.0. Liver exposure was much lower, rising only from 0.09 to 1.4, with a correspondingly weaker suppression of the reaction product there. The compound accumulates in the two tissues the metabolic hypothesis cares about and largely spares the organ where the enzyme is most abundant — which is, on the argument of Section 22, probably the right way round.

20Selectivity, and the off-target nobody screened for

The 2018 paper's selectivity claim is repeated everywhere: the compound is described as showing “exceptional selectivity”, not inhibiting DNA methyltransferase 1, protein arginine methyltransferase 3, catechol O-methyltransferase, nicotinamide phosphoribosyltransferase or sirtuin 1. Those five results are real, and the panel has three limitations that are not usually quoted with it.

First, the concentrations. Catechol O-methyltransferase showed ten per cent inhibition at 600 µM with no concentration dependence; sirtuin 1 showed a “minor reduction” at 600 µM. Second, the nicotinamide phosphoribosyltransferase assay failed above 100 µM because the compound interfered with the readout, and the gap was filled with a different analogue whose data are not shown. Third, and most important, the panel contains five enzymes. It contains no receptor, no transporter, no ion channel, and none of the enzyme's own close relatives.

That last omission matters structurally. Searching the human NNMT structure against the structural database returns indolethylamine N-methyltransferase at 1.1 Å root-mean-square deviation over 257 alpha-carbons and 52 per cent sequence identity, and phenylethanolamine N-methyltransferase at 1.5 Å and 39 per cent. The cofactor site is conserved between them; only the acceptor pocket has diverged. Indolethylamine N-methyltransferase methylates tryptamine and serotonin. No published selectivity screen of 5-amino-1MQ has ever included it. More broadly, a high-throughput screen of 27,574 compounds across six small-molecule methyltransferases found that about seventy-two per cent of NNMT hits also inhibited at least one of the others — this is a promiscuous pocket, and five counter-targets is not a selectivity package.

In 2024 someone finally ran a broad panel, and it found something.

21Safety: what exists, and what does not

The safety record for 5-amino-1MQ consists entirely of secondary observations made inside experiments designed to measure something else. There is no toxicology study of any kind. Set out honestly, this is what exists: