Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Ginkgo Biloba | Phenibut | |
|---|---|---|
| Category | Nootropics | Nootropics |
| Standard Dose | 120-240 mg/day of standardized extract (24% flavone glycosides, 6% terpene lactones) divided into 2-3 doses | 250-750 mg as needed, maximum 1-2 times per week (for educational context — carries significant dependence risk) |
| Timing | With or without food. Split into 2-3 doses throughout the day. Effects may take 4-6 weeks to manifest. | On an empty stomach (food significantly reduces absorption). Onset 2-4 hours. Effects last 4-8 hours with residual effects up to 24 hours. Half-life approximately 5.3 hours. |
| Cycle Duration | Ongoing; no cycling required. Clinical trials typically run 22-26 weeks. | STRICTLY intermittent use only — maximum 1-2 times per week. NEVER use daily for more than 1 week. Tolerance develops within days, leading to dose escalation and dependence. |
| Evidence Level | strong_human | moderate_human |
Standardized extract (EGb 761) contains flavonoid glycosides (24%) and terpene lactones (6% — ginkgolides A/B/C and bilobalide) that act through multiple pathways: potent free radical scavenging and inhibition of membrane lipid peroxidation; antagonism of platelet-activating factor (PAF) via ginkgolides; enhancement of cerebral blood flow through nitric oxide-mediated vasodilation and reduced blood viscosity; and increased prefrontal dopamine and acetylcholine release via acylated flavonol glycosides. Bilobalide provides direct neuroprotection against excitotoxicity and mitochondrial dysfunction.
120-240 mg/day of standardized extract (24% flavone glycosides, 6% terpene lactones) divided into 2-3 doses
With or without food. Split into 2-3 doses throughout the day. Effects may take 4-6 weeks to manifest.
Ongoing; no cycling required. Clinical trials typically run 22-26 weeks.
Beta-phenyl derivative of GABA that crosses the blood-brain barrier (unlike GABA itself) due to the addition of a phenyl ring. Acts as a full agonist at GABA-B receptors with 30-68x lower affinity than baclofen, requiring correspondingly higher doses. Also binds to and blocks alpha-2-delta subunit-containing voltage-dependent calcium channels (VDCCs), making it a gabapentinoid similar to gabapentin and pregabalin. At low concentrations, mildly increases dopamine levels in the brain, providing stimulatory and nootropic effects alongside anxiolysis. Weak agonist activity at GABA-A receptors at higher doses.
250-750 mg as needed, maximum 1-2 times per week (for educational context — carries significant dependence risk)
On an empty stomach (food significantly reduces absorption). Onset 2-4 hours. Effects last 4-8 hours with residual effects up to 24 hours. Half-life approximately 5.3 hours.
STRICTLY intermittent use only — maximum 1-2 times per week. NEVER use daily for more than 1 week. Tolerance develops within days, leading to dose escalation and dependence.
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