Quick Comparison

FasoracetamPhosphatidylserine
Half-Life1.5-2.5 hoursNot well-characterized orally; brain PS turns over slowly
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: 100-300 mg daily in 1-3 doses. Most studies use 300 mg daily. Soy-derived and sunflower-derived forms are both effective. Take with food for absorption.
AdministrationOral or sublingual. Sublingual may provide better absorption.Oral (softgels, capsules). Soy-derived or sunflower-derived. Take with fat for absorption.
Research Papers5 papers10 papers
Categories

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.

Phosphatidylserine

PS is a structural component of neuronal membranes, maintaining membrane fluidity and supporting receptor function, ion channel activity, and neurotransmitter release. It localizes preferentially to the inner leaflet of the plasma membrane via flippase enzymes (P4-ATPases), where it serves as a cofactor for protein kinase C (PKC) isoforms alpha, beta, and gamma — PKC activation phosphorylates substrates including MARCKS and GAP-43, critical for synaptic plasticity and memory consolidation. PS modulates the HPA axis via glucocorticoid receptor feedback, reducing cortisol by 15-30% in stressed individuals. It facilitates choline transport via high-affinity choline transporter (CHT1) into presynaptic terminals, supporting acetylcholine synthesis by choline acetyltransferase. PS also regulates NMDA receptor function and supports Na+/K+-ATPase activity. Downstream, PS enhances CREB phosphorylation and BDNF expression in hippocampal neurons.

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.

Phosphatidylserine

Common

Mild gastrointestinal discomfort, insomnia at high doses.

Serious

May interact with blood thinners.

Rare

Allergic reaction in soy-sensitive individuals (use sunflower-derived).

Full Profiles