Quick Comparison

AshwagandhaFasoracetam
Half-Life6-12 hours (withanolides)1.5-2.5 hours
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: 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.
AdministrationOral (capsules, powder). Standardized extracts (KSM-66 or Sensoril) are preferred over raw root powder for consistent dosing.Oral or sublingual. Sublingual may provide better absorption.
Research Papers9 papers5 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.

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.

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.

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.

Full Profiles