Agmatine (sulfate) Compound Monograph

Agmatine (sulfate) at a Glance

Agmatine is what arginine becomes when an enzyme removes its carboxyl group. That single change turns a common dietary amino acid into a biogenic amine with genuine neurotransmitter-like behaviour — it is synthesised in the brain, stored in vesicles, released on stimulation, and taken back up, which is the standard checklist for a signalling molecule rather than a metabolic intermediate.

What makes it unusual is how many things it touches. Agmatine blocks NMDA receptors, binds imidazoline receptors, inhibits several forms of nitric-oxide synthase, and modulates alpha-2 adrenergic signalling. Most supplements have one plausible mechanism and a stack of speculation on top; agmatine has four well-characterised ones. The difficulty is the reverse of the usual problem — plenty of pharmacology, very little human outcome data.

The honest state of play: the credible human evidence is in neuropathic pain, and even that rests on two small studies from a narrow research base. The mood, neuroprotection and exercise-”pump” claims that drive most sales are extrapolated from animal work and mechanism, not demonstrated in people.

What It’s Used For

Neuropathic pain — the one use with human trial support, and the one where the mechanism looks earned rather than accidental.
Depression — heavily promoted, resting on a large animal literature and a single uncontrolled 3-patient pilot.
Neuroprotection — mechanistically the most plausible unproven use. Preclinical only.
Exercise “pump” / ergogenic — sold on nitric oxide, when agmatine mostly inhibits nitric-oxide synthase. The marketing rationale runs backwards.

The right way to hold all of it: one narrow, real, small-scale finding surrounded by a lot of confident marketing that has not been tested.

How It Works

Arginine decarboxylase strips the carboxyl group from arginine to produce agmatine; agmatinase eventually breaks it down. Between those two points it acts on a spread of targets that happen to converge on pain and neuronal excitability — which is why the pain finding is the one that looks mechanistically earned rather than accidental.

The most relevant action for pain is NMDA-receptor antagonism. Chronic and neuropathic pain involve central sensitisation, in which repeated input makes spinal neurons progressively more responsive, and NMDA receptors are central to that process. Blocking them is an established analgesic strategy — ketamine works this way — and agmatine is a much weaker, better-tolerated version of the same idea.

Alongside that, agmatine inhibits nitric-oxide synthase, damping a pathway that contributes to inflammatory and neuropathic pain signalling. It also binds imidazoline receptors, the same family clonidine acts on, which is where its blood-pressure relevance comes from and why caution around cardiovascular medication is sensible. And it modulates alpha-2 adrenergic signalling, another established analgesic route.

Two practical notes. The nitric-oxide point cuts against the sports marketing: agmatine mostly inhibits NO production, so selling it as a vasodilating pump agent inverts its actual pharmacology. And the dose is large — 2.67 g/day in both human studies — which reflects modest potency, not an aggressive protocol.

The full trial record is in Pharmacology & Research below.

Pharmacology & Research

Agmatine is decarboxylated arginine — a biogenic amine that behaves like a neurotransmitter (synthesised in brain, stored in vesicles, released on stimulation, and taken back up) rather than a passive metabolic intermediate. What makes it unusual among supplements is that it has four well-characterised molecular actions — NMDA-receptor antagonism, imidazoline-receptor binding, nitric-oxide synthase inhibition and α2-adrenergic modulation — where most supplements have one plausible mechanism and a stack of speculation on top ^{4Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →}.

The problem is the reverse of the usual one: plenty of pharmacology, very little human outcome data. The credible human evidence is concentrated in neuropathic pain, and even that rests on one small RCT plus an uncontrolled case series ^{1,2Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}; the mood, neuroprotection and exercise-”pump” claims that drive most sales are extrapolated from animal work and mechanism, not demonstrated in people. A form note that matters for label-reading: it is sold as agmatine sulfate, so the stated weight may be the salt, not the free base.

Best-supported:neuropathic pain — one randomised, double-blind, placebo-controlled trial in lumbar disc radiculopathy (2.67 g/day) ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}, backed by a small open-label case series in painful small-fibre neuropathy ^{2Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}.

Emerging / cautiously endorsed:major depression — a single human pilot reported remission at low doses, but n=3, open-label and single-author, sitting on top of a large animal literature ^{8,9,10,11Reference 8Shopsin B · 2013The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study — open-label human pilotView study →Reference 9Kale M et al. · 2020AnimalAgmatine modulates anxiety and depression-like behaviour in diabetic insulin-resistant rats — animal studyView study →Reference 10Vinchurney MD et al. · 2023AnimalAgmatine prevents the manifestation of impulsive burying and depression-like behaviour in progesterone withdrawn female rats — animal studyView study →Reference 11Watts D et al. · 2019ReviewAgmatine as a potential therapeutic intervention in bipolar depression: the preclinical landscape — reviewView study →}.

Popular but thin / overhyped:the exercise “pump” claim is not just unproven but mechanistically backwards — agmatine mostly inhibits nitric-oxide synthase, the opposite of a vasodilating pump agent ^{4Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →}; neuroprotection is preclinical only ^{12Reference 12Sezer A et al. · 2014RCTNeuroprotective effects of agmatine in experimental peripheral nerve injury in rats: a prospective randomized and placebo-controlled trial — animal randomised controlled trialView study →}.

The honest miss / caveat:the entire human base is a handful of small studies from a narrow group of investigators, and human pharmacokinetics have never been measured — oral bioavailability and half-life are known only from rats ^{6Reference 6Clements BM et al. · 2023Biodistribution of agmatine to brain and spinal cord after systemic delivery — animal pharmacokinetic studyView study →}.

Evidence by IndicationStrength of support · Beta

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.

The best human data are here. A study combining an open-label dose-escalation phase with a randomised, double-blind, placebo-controlled trial found that dietary agmatine sulfate (2.67 g/day for 14 days) improved pain and quality-of-life scores in herniated lumbar disc-associated radiculopathy versus placebo — average pain measures improved 26.7% of baseline in the agmatine group (analysed n=31) against 6.0% on placebo (n=30), with quality-of-life scores improving 70.8% against 20.0% (both P ≤ 0.05) ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}.

A later open-label pilot case series in painful small-fibre neuropathy reported roughly a 46% reduction in pain intensity on the same 2.67 g/day dose, but with no placebo control and only about a dozen patients ^{2Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}.

The mechanism looks earned rather than accidental: NMDA-receptor antagonism — the same target ketamine hits, agmatine being a much weaker, better-tolerated version — plus NOS inhibition and α2-adrenergic modulation all converge on the central sensitisation that drives neuropathic pain ^{4,7Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}.

Gap: two small studies from one narrow research base, only one of them controlled and only 14 days long; no dose-ranging trial, so the single 2.67 g/day figure is the entire evidence-based dose.

Mechanisms

Target / pathway	Effect	Relevant to
NMDA receptor (GluN2B subunit)	Antagonist	Neuropathic paindepressionneuroprotection
Imidazoline receptors (I1/I2)	Ligand / binding	Blood-pressure effectsopioid-tolerance modulationcardiovascular caution
Nitric-oxide synthase (nNOS/iNOS)	Inhibition	Painneuroprotection — and contradicts the “pump” marketing
α2-adrenergic signalling	Modulation (the clonidine-like family)	Analgesiablood-pressure relevance
Polyamine metabolism	Regulates intracellular polyamine content	Proposed antidepressant and neuroprotective routes (preclinical)
Arginine decarboxylase → agmatinase	Synthesis from arginine, then breakdown	Endogenous turnover; no dietary requirement

Agmatine’s four actions happen to converge on pain and neuronal excitability, which is why the pain finding looks mechanistically earned. The imidazoline and NOS actions are also why cardiovascular caution is sensible — and the NOS point is why the sports-supplement rationale is internally inconsistent ^{4,5,7Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →Reference 5Lowry JA et al. · 2014ReviewSignificance of the imidazoline receptors in toxicology — reviewView study →Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}.

Pharmacokinetics

There are no human pharmacokinetic data — a real gap for a supplement people take daily. The quantitative picture comes from a validated rat study: oral bioavailability of 29–35%, a short plasma half-life (about 15 minutes intravenously, extended to 74–117 minutes orally, suggesting flip-flop kinetics), and demonstrable crossing of both the intestinal epithelium and the blood-brain barrier, with distinct kinetics in brain versus spinal cord ^{6Reference 6Clements BM et al. · 2023Biodistribution of agmatine to brain and spinal cord after systemic delivery — animal pharmacokinetic studyView study →}.

The short half-life is consistent with the large 2.67 g/day dose used in the human pain trials — modest potency and rapid clearance, not an aggressive protocol. Because agmatine is a small amine given at gram scale, that also explains the mild gastrointestinal complaints seen in the dose-escalation work ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}.

Clinical trials

Agmatine is an off-patent dietary ingredient with essentially no industry trial pipeline. ClinicalTrials.gov lists only two interventional agmatine studies — the radiculopathy trial (completed, n=79) and the small-fibre-neuropathy case series (status listed as unknown) — with no active or planned registered trials. Preclinical work, by contrast, is extensive across pain, mood and neuroprotection models.

Completed	Unknown / lapsed	Planned	Terminated	Preclinical
1	1	0	0	Many

Last checked: August 2026.

Dietary Sources

Agmatine is produced endogenously from arginine by arginine decarboxylase, so there is no dietary requirement and no deficiency state ^{3,4Reference 3Piletz JE et al. · 2013ReviewAgmatine: clinical applications after 100 years in translation — reviewView study →Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →}. Small amounts occur in fermented foods — beer, wine, aged cheese, soy sauce, some fermented meats — where bacterial decarboxylases generate it from arginine, the same chemistry that produces the other biogenic amines in fermented products. Gut bacteria also synthesise it ^{4Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →}.

Source	Rough agmatine content	Note
Supplemental agmatine sulfate	250 mg–2.67 g per dose	Manufactured; the only way to reach studied doses
Fermented foods (beer, wine, aged cheese, soy sauce, fermented meats)	Trace to low milligram amounts per serving	Bacterial arginine decarboxylase; a biogenic-amine footnote
Gut microbiota	Endogenous, variable	Contributes to the body pool; not a controllable “intake”

Food-level quantities are trivial against the 2.67 g/day used in the trials, so dietary agmatine is a footnote rather than a route to a supplemental effect. Supplemental agmatine is manufactured and sold as agmatine sulfate — the salt form, which matters when reading a label, since the stated weight may be the sulfate rather than the free base.

Dosage

These are doses studied in research, not a personal recommendation.

The studied dose is a single figure: 2.67 g/day of agmatine sulfate, used in both human studies ^{1,2Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}. There is no established range, because no dose-ranging trial exists to build one from — the open-label phase of the radiculopathy study escalated up to 3.56 g/day and found the higher doses brought mild-to-moderate diarrhoea and nausea, which resolved on stopping ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}.

Context	Dose	Notes
Neuropathic-pain trials	2.67 g/day agmatine sulfate	The only efficacy-tested dose; 14 days, controlled ^{1,2Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}
Depression pilot	2–3 mg/day	Uncontrolled n=3 pilot, roughly 1,000× lower — treat as anecdote, not a protocol ^{8Reference 8Shopsin B · 2013The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study — open-label human pilotView study →}
Common supplement use	A few hundred mg/day	Substantially less studied; extrapolating down from 2.67 g is an assumption

Duration studied is short — 14 days in the controlled trial — so long-term dosing is uncharacterised. Check whether a label means agmatine or agmatine sulfate, since the sulfate salt is what is sold and the free-base weight is lower.

Safety

Short-term tolerability looks fine. Almost everything else is unstudied, and the cardiovascular pharmacology deserves respect.

Safety at a Glance

Low / no toxicityCardiac cautionDrug interactions

Well tolerated in the short trials. No treatment-related adverse events over the two-week controlled study; toxicity appears low ^{1,2Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}.
Acts on blood-pressure pathways. Imidazoline-receptor binding and nitric-oxide synthase inhibition both point at cardiovascular effects — caution alongside blood-pressure medication ^{4,5,7Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →Reference 5Lowry JA et al. · 2014ReviewSignificance of the imidazoline receptors in toxicology — reviewView study →Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}.
GI upset at gram-level doses. Nausea and loose stools, seen mainly at the higher escalation doses ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}.
Long-term safety not established. The longest controlled human exposure is two weeks.
Plausible but untested interactions with NMDA-active drugs and opioid analgesics ^{7Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}.
Do not use in pregnancy or lactation — see the box below.

Full Safety & Interactions Detail

Agmatine was reported as well tolerated over the short durations studied, and its toxicity appears low ^{1,2Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →Reference 2Rosenberg ML et al. · 2020Case reportEvidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case seriesView study →}. Mild gastrointestinal upset — nausea, loose stools — is the usual complaint at gram-level doses, and was seen mainly at the higher escalation doses ^{1Reference 1Keynan O et al. · 2010RCTSafety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trialView study →}.

Cardiovascular caution is the meaningful one. Agmatine binds imidazoline receptors — the target family clonidine acts through — and inhibits nitric-oxide synthase. Both are blood-pressure-relevant pathways, so caution is reasonable for anyone on cardiovascular or antihypertensive medication until interactions are properly characterised ^{4,5,7Reference 4Akasaka N et al. · 2020ReviewThe therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — reviewView study →Reference 5Lowry JA et al. · 2014ReviewSignificance of the imidazoline receptors in toxicology — reviewView study →Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}.
Other plausible interactions: additive effects with NMDA-active drugs and, on mechanistic grounds, with opioid analgesics — agmatine has been studied preclinically for its effect on opioid tolerance ^{7Reference 7Wu N et al. · 2008ReviewAgmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — reviewView study →}. None of this has been tested clinically.
Long-term safety is not established. The controlled human exposure runs to two weeks, which is thin ground for a supplement people take continuously.

Scope disclosure. Interactions were assessed partially — cardiovascular and antihypertensive drugs (via the imidazoline and NOS pathways) and, on mechanistic grounds, NMDA-active drugs and opioids were flagged; none has been formally tested in humans, and no systematic drug-interaction study exists. Pregnancy and lactation were not assessed — no human data exist, and avoidance is advised on mechanistic grounds. No Upper Limit exists and there is no dose-ranging trial; absence of a UL does not mean higher doses are safe. Two weeks of good tolerability in roughly a hundred people does not establish that daily long-term use is safe.

Pregnancy & Lactation

Not established in pregnancy Not established in lactation

Do not use. No human data exist for supplemental agmatine in pregnancy or lactation. It acts on NMDA and nitric-oxide signalling, both of which have roles in development, so this is an unstudied exposure with a mechanistically plausible route to relevance rather than an inert one. Pregnant or breastfeeding people should not use it without discussing it with a qualified practitioner.

References

Keynan O, et al. (2010). Safety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy: an open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial — randomised controlled trial. Pain Medicine. https://pubmed.ncbi.nlm.nih.gov/20447305/
Rosenberg ML, et al. (2020). Evidence for dietary agmatine sulfate effectiveness in neuropathies associated with painful small fiber neuropathy: a pilot open-label consecutive case series study — open-label case series. Nutrients. https://pubmed.ncbi.nlm.nih.gov/32102167/
Piletz JE, et al. (2013). Agmatine: clinical applications after 100 years in translation — review. Drug Discovery Today. https://pubmed.ncbi.nlm.nih.gov/23769988/
Akasaka N, et al. (2020). The therapeutic and nutraceutical potential of agmatine, and its enhanced production using Aspergillus oryzae — review. Amino Acids. https://pubmed.ncbi.nlm.nih.gov/30915570/
Lowry JA, et al. (2014). Significance of the imidazoline receptors in toxicology — review. Clinical Toxicology. https://pubmed.ncbi.nlm.nih.gov/24666288/
Clements BM, et al. (2023). Biodistribution of agmatine to brain and spinal cord after systemic delivery — animal pharmacokinetic study. Journal of Pharmacology and Experimental Therapeutics. https://pubmed.ncbi.nlm.nih.gov/37770201/
Wu N, et al. (2008). Agmatine and imidazoline receptors: their role in opioid analgesia, tolerance and dependence — review. Cellular and Molecular Neurobiology. https://pubmed.ncbi.nlm.nih.gov/17653850/
Shopsin B (2013). The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study — open-label human pilot. Acta Neuropsychiatrica. https://pubmed.ncbi.nlm.nih.gov/25287313/
Kale M, et al. (2020). Agmatine modulates anxiety and depression-like behaviour in diabetic insulin-resistant rats — animal study. Brain Research. https://pubmed.ncbi.nlm.nih.gov/32758481/
Vinchurney MD, et al. (2023). Agmatine prevents the manifestation of impulsive burying and depression-like behaviour in progesterone withdrawn female rats — animal study. Hormones and Behavior. https://pubmed.ncbi.nlm.nih.gov/37163843/
Watts D, et al. (2019). Agmatine as a potential therapeutic intervention in bipolar depression: the preclinical landscape — review. Expert Opinion on Therapeutic Targets. https://pubmed.ncbi.nlm.nih.gov/30764678/
Sezer A, et al. (2014). Neuroprotective effects of agmatine in experimental peripheral nerve injury in rats: a prospective randomized and placebo-controlled trial — animal randomised controlled trial. Turkish Neurosurgery. https://pubmed.ncbi.nlm.nih.gov/24831360/