Quick Comparison
| Agmatine Sulfate | CDP-Choline | |
|---|---|---|
| Half-Life | 2-3 hours | 56-71 hours (long elimination half-life) |
| Typical Dosage | Standard: 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. |
| Administration | Oral (powder, capsules). Take on empty stomach for best absorption. | Oral (capsules, tablets). Very well-absorbed with nearly 100% oral bioavailability. |
| Research Papers | 10 papers | 10 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.
Full Profiles
Agmatine Sulfate →
A metabolite of L-arginine produced by decarboxylation. Agmatine is an endogenous neuromodulator that acts on multiple receptor systems — it blocks NMDA receptors, activates imidazoline receptors, inhibits nitric oxide synthase, and modulates opioid signaling. This makes it useful for neuropathic pain, mood, stress resilience, and as a complement to other nootropics. Also enhances insulin sensitivity and nitric oxide production.
CDP-Choline →
Also known as Citicoline, this is a naturally occurring compound that provides both choline and cytidine (which converts to uridine in the body). This dual action supports both acetylcholine synthesis and cell membrane repair, making it both a cognitive enhancer and a neuroprotectant. Prescribed in many countries for stroke recovery and cognitive decline.