Quick Comparison

FasoracetamReishi
Half-Life1.5-2.5 hoursBioactive compounds accumulate with daily use
Typical DosageStandard: 20-100 mg sublingually or orally, 1-3 times daily. Many users find 20-40 mg effective. Clinical trials for ADHD used 100-400 mg twice daily.Standard: 1000-3000 mg daily of extract. Dual-extract (water + alcohol extraction) preferred to capture both polysaccharides and triterpenes. Take in the evening due to calming effects. Spore oil: 500-1000 mg daily. Effects build over 2-4 weeks.
AdministrationOral or sublingual. Sublingual may provide better absorption.Oral (capsules, powder, tincture, tea). Dual-extract preferred. Bitter taste in powder/tea form.
Research Papers5 papers8 papers
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Mechanism of Action

Fasoracetam

Fasoracetam upregulates GABA-B receptor (GABA-B1/GABA-B2 heterodimer) expression and function, which is unique among racetams — this receptor upregulation is potentially beneficial for restoring GABAergic sensitivity after prolonged benzodiazepine or phenibut use. It enhances group II metabotropic glutamate receptor (mGluR2/mGluR3) signaling, which modulates presynaptic glutamate release and reduces excitotoxicity. Fasoracetam increases acetylcholine release in the cerebral cortex via modulation of choline acetyltransferase activity and vesicular acetylcholine transporter function. It may also modulate the glutamatergic system through mGluR5. The combination of GABAergic (GABA-B-mediated inhibition), glutamatergic (mGluR modulation), and cholinergic enhancement provides anxiolytic effects alongside cognitive enhancement. Clinical trials focus on ADHD patients with GRM (glutamate receptor) gene variants.

Reishi

Reishi's triterpenes (ganoderic acids A, C, D, H; ganoderenic acids) modulate the HPA axis by reducing CRH and ACTH release, lowering cortisol via glucocorticoid receptor feedback. Ganoderic acids have direct sedative effects through GABA-A receptor modulation (possibly allosteric at the benzodiazepine site) and 5-HT2A/2C serotonergic modulation. Beta-(1,3)-(1,6)-glucan polysaccharides bind Dectin-1 and complement receptor 3 (CR3) on macrophages, natural killer cells, and dendritic cells, activating NF-kB and MAPK signaling for immune modulation. Reishi inhibits histamine release from mast cells via Fc epsilon RI downregulation and stabilizes mast cell membranes (anti-allergic effect). Antioxidant properties involve upregulation of superoxide dismutase (SOD1/SOD2), catalase, and glutathione peroxidase. Ganoderic acids may also inhibit 5-alpha-reductase and ACE.

Risks & Safety

Fasoracetam

Common

Headache, fatigue, mild digestive discomfort.

Serious

Limited long-term human safety data.

Rare

Low mood, brain fog, loss of motivation at very high doses.

Reishi

Common

Digestive discomfort, dry mouth, dizziness.

Serious

Rare hepatotoxicity reported — avoid with liver disease. May interact with blood thinners and immunosuppressants.

Rare

Allergic reaction, nosebleeds.

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