CDP-Choline (Citicoline) vs Huperzine A

Mechanism

Prodrug that is hydrolyzed to choline and cytidine upon oral ingestion. Choline supports acetylcholine synthesis and phosphatidylcholine membrane repair. Cytidine is converted to uridine, which enhances synaptic membrane synthesis via the Kennedy pathway and upregulates dopamine receptor density. This dual mechanism — cholinergic support plus dopaminergic modulation — is unique among choline sources.

Standard Dosing

250-500 mg/day

Timing

Morning or split morning/afternoon. With or without food.

Cycle Duration

Ongoing; no cycling required

Side Effects

• GI distress
• Headache
• Insomnia (due to dopaminergic activity)
• Diarrhea at high doses

Contraindications

• Known hypersensitivity to citicoline

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Mechanism

Potent, selective, and reversible inhibitor of acetylcholinesterase (AChE), derived from the club moss Huperzia serrata. Exhibits preference for the tetrameric G4 form of AChE predominant in the mammalian brain. Eight-fold more potent than donepezil and two-fold more potent than rivastigmine at AChE inhibition. Crosses the BBB efficiently. Also antagonizes NMDA receptors at high concentrations and provides neuroprotection via attenuation of oxidative stress, regulation of apoptotic proteins (Bcl-2, Bax, P53, caspase-3), and upregulation of NGF.

Standard Dosing

50-200 mcg twice daily

Timing

Morning and early afternoon. With or without food.

Cycle Duration

Cycle 2-4 weeks on, 1-2 weeks off to prevent AChE downregulation

Side Effects

• Nausea
• Diarrhea
• Sweating
• Blurred vision
• Muscle twitching
• Bradycardia at high doses

Contraindications

• Bradycardia
• Asthma/COPD (cholinergic bronchoconstriction)
• GI obstruction
• Concurrent use of prescription AChE inhibitors
• Peptic ulcer disease

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