Quick Comparison
| CDP-Choline | Methylene Blue | |
|---|---|---|
| Half-Life | 56-71 hours (long elimination half-life) | 5-6 hours |
| Typical Dosage | 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. | Nootropic dose: 0.5-2 mg/kg body weight (typically 30-60 mg for most adults). Pharmaceutical grade USP only — never use industrial or aquarium-grade. Start at the lowest dose. Turns urine blue/green (harmless). |
| Administration | Oral (capsules, tablets). Very well-absorbed with nearly 100% oral bioavailability. | Oral (solution, capsules). Must be pharmaceutical/USP grade. Sublingual for faster absorption. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
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.
Methylene Blue
Methylene blue has a unique property: it acts as an alternative electron carrier in the mitochondrial electron transport chain, cycling between oxidized (blue) and reduced (leuco) forms. It can accept electrons from Complex I (NADH) and donate them directly to cytochrome c, bypassing dysfunctional Complex II and III—maintaining ATP production when mitochondria are damaged or in hypoxic conditions. Methylene blue inhibits nitric oxide synthase (NOS), reducing NO production and the formation of peroxynitrite (ONOO-), a potent oxidant that damages mitochondria. It acts as a redox cycler with antioxidant properties and may enhance cytochrome c oxidase (Complex IV) activity. At low doses, it inhibits tau protein aggregation and tau-tau interactions (relevant to Alzheimer's pathology) and may improve mitochondrial respiration through multiple mechanisms.
Risks & Safety
CDP-Choline
Common
Headache, nausea, diarrhea, insomnia.
Serious
Very safe — extensive clinical safety data.
Rare
Blurred vision, chest pain, allergic reactions.
Methylene Blue
Common
Blue/green discoloration of urine and potentially skin at higher doses, nausea, headache.
Serious
Serotonin syndrome risk when combined with SSRIs, SNRIs, or MAOIs — DO NOT combine. Contraindicated in G6PD deficiency (can cause hemolytic anemia).
Rare
Confusion, shortness of breath, chest pain.
Full Profiles
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.
Methylene Blue →
A synthetic dye first made in 1876 that has remarkable medicinal properties. At low doses (0.5-4 mg/kg), methylene blue acts as a mitochondrial electron carrier, enhancing cellular respiration and ATP production. It is the only known compound that can donate and accept electrons in the mitochondrial electron transport chain, essentially serving as a backup energy pathway when mitochondria are stressed.