Quick Comparison

Agmatine SulfateCDP-Choline
Half-Life2-3 hours56-71 hours (long elimination half-life)
Typical DosageStandard: 500-2000 mg daily in 1-3 doses. For mood: 1000-2000 mg. For pain: 1000-2500 mg. Take on empty stomach. Agmatine sulfate is the most common supplement form. May enhance the effects of some nootropics and medications — research interactions.Standard: 250-500 mg daily in 1-2 doses. Clinical (stroke/cognitive decline): 500-2000 mg daily. Most nootropic users find 250-500 mg sufficient.
AdministrationOral (powder, capsules). Take on empty stomach for best absorption.Oral (capsules, tablets). Very well-absorbed with nearly 100% oral bioavailability.
Research Papers10 papers10 papers
Categories

Mechanism of Action

Agmatine Sulfate

Agmatine is a polyamine neuromodulator with multiple targets: (1) NMDA receptor antagonist at the polyamine binding site (GluN1/GluN2B) — reduces excitotoxicity, pain signaling, and blocks the receptor's open channel. (2) Imidazoline I1 and I2 receptor agonist — I1 in the rostral ventrolateral medulla reduces sympathetic tone; I2 modulates monoamine oxidase and provides anxiolytic/antidepressant effects. (3) Selective nNOS (neuronal nitric oxide synthase) inhibitor — reduces peroxynitrite formation and oxidative stress while preserving eNOS (endothelial) function for vascular health. (4) Alpha-2 adrenergic receptor agonist — reduces norepinephrine release from locus coeruleus, promoting calm. (5) Modulates opioid receptors — enhances mu-opioid analgesia, potentiates delta-opioid, and may reduce tolerance via nitric oxide and NMDA mechanisms.

CDP-Choline

CDP-Choline is hydrolyzed by nucleotidases and phosphatases into choline and cytidine after oral ingestion. Choline enters the acetylcholine synthesis pathway via choline acetyltransferase. Cytidine is phosphorylated to CTP and converted to uridine monophosphate (UMP), which enters the Kennedy pathway and stimulates the synthesis of phosphatidylcholine via the enzyme CTP:phosphocholine cytidylyltransferase — phosphatidylcholine is a critical component of neuronal cell membranes and synaptic vesicles. This dual mechanism simultaneously boosts neurotransmitter production and repairs membrane damage from oxidative stress or ischemia. CDP-Choline also increases dopamine D2 receptor density in the striatum and enhances dopamine release. It may modulate glutamate excitotoxicity and support mitochondrial function.

Risks & Safety

Agmatine Sulfate

Common

Mild gastrointestinal discomfort, diarrhea at high doses.

Serious

May potentiate opioid medications (increased sedation risk). May lower blood pressure.

Rare

Headache, nausea.

CDP-Choline

Common

Headache, nausea, diarrhea, insomnia.

Serious

Very safe — extensive clinical safety data.

Rare

Blurred vision, chest pain, allergic reactions.

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