Quick Comparison

AshwagandhaPhosphatidylserine
Half-Life6-12 hours (withanolides)Not well-characterized orally; brain PS turns over slowly
Typical DosageKSM-66 extract: 300-600 mg daily. Sensoril extract: 125-250 mg daily. Root powder: 3-6 g daily. Best taken with food. Can be taken morning or evening (does not cause drowsiness in most people).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 (capsules, powder). Standardized extracts (KSM-66 or Sensoril) are preferred over raw root powder for consistent dosing.Oral (softgels, capsules). Soy-derived or sunflower-derived. Take with fat for absorption.
Research Papers9 papers10 papers
Categories

Mechanism of Action

Ashwagandha

Ashwagandha's withanolide compounds (withaferin A, withanolide A, withanone) modulate the hypothalamic-pituitary-adrenal (HPA) axis, reducing corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) signaling, thereby lowering cortisol production by 25-30% in stressed individuals. It acts as a GABA-A receptor positive allosteric modulator at the benzodiazepine site, producing anxiolytic effects without sedation. Ashwagandha inhibits acetylcholinesterase (AChE), raising acetylcholine levels in the hippocampus and cortex. The withanolides have anti-inflammatory properties via inhibition of NF-κB and COX-2, and antioxidant effects that reduce neuroinflammation and oxidative stress. It may support neurogenesis through upregulation of BDNF and its receptor TrkB, and modulation of the PI3K/Akt pathway.

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

Ashwagandha

Common

Gastrointestinal discomfort, drowsiness at higher doses, thyroid hormone elevation.

Serious

Can cause hyperthyroidism in susceptible individuals — avoid with thyroid conditions without medical oversight. Rare liver injury reports.

Rare

Vertigo, nasal congestion, sexual dysfunction.

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).

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