Quick Comparison
| Ashwagandha | B-Complex | |
|---|---|---|
| Half-Life | 6-12 hours (withanolides) | Water-soluble; excreted daily (except B12 which is stored) |
| Typical Dosage | KSM-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: A quality B-complex providing 25-100 mg of B1, B2, B3, B5, B6, plus 400-800 mcg folate (as methylfolate) and 500-1000 mcg B12 (as methylcobalamin). Methylated forms preferred for B9 and B12 (folate → methylfolate, B12 → methylcobalamin). Take in the morning — B vitamins can be mildly energizing. |
| Administration | Oral (capsules, powder). Standardized extracts (KSM-66 or Sensoril) are preferred over raw root powder for consistent dosing. | Oral (capsules, tablets, sublingual). Methylated forms preferred for B9 and B12. Take with breakfast. |
| Research Papers | 9 papers | 10 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.
B-Complex
Each B vitamin serves specific neurological functions: B1 (thiamine) — cofactor for transketolase (pentose phosphate pathway), pyruvate dehydrogenase, and alpha-ketoglutarate dehydrogenase; essential for glucose metabolism and ATP production in neurons. B2 (riboflavin) — precursor to FAD/FMN, cofactors for Complex I and II of the electron transport chain, and glutathione reductase. B3 (niacin/niacinamide) — precursor to NAD+/NADPH via the salvage pathway; NAD+ is substrate for sirtuins, PARP, and 400+ dehydrogenases. B5 (pantothenic acid) — component of coenzyme A, required for acetylcholine synthesis via choline acetyltransferase and for fatty acid oxidation. B6 (pyridoxine) — cofactor for AADC (5-HTP to serotonin, L-DOPA to dopamine), GABA synthesis (GAD), and homocysteine metabolism. B9 (folate) — tetrahydrofolate donates methyl groups for dTMP and purine synthesis, and for homocysteine remethylation. B12 (cobalamin) — cofactor for methionine synthase (myelin maintenance) and methylmalonyl-CoA mutase.
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.
B-Complex
Common
Bright yellow urine (harmless — riboflavin excretion), mild nausea.
Serious
Very safe at standard doses. B6 can cause peripheral neuropathy at >200 mg daily for extended periods.
Rare
Flushing from niacin (B3) if non-flush form is not used.
Full Profiles
Ashwagandha →
An Ayurvedic adaptogen used for over 3,000 years that has become one of the most popular and well-studied supplements for stress, anxiety, and cognitive function. Ashwagandha (Withania somnifera) significantly reduces cortisol levels, improves stress resilience, and enhances memory and reaction time. KSM-66 and Sensoril are the two most studied standardized extracts.
B-Complex →
The B vitamins (B1, B2, B3, B5, B6, B9, B12) are essential coenzymes in brain energy metabolism, neurotransmitter synthesis, and methylation reactions. Deficiency in any B vitamin impairs cognitive function. B12 and folate deficiency specifically cause irreversible neurological damage if untreated. A high-quality B-complex is foundational for any nootropic regimen, particularly for vegetarians, older adults, and those under chronic stress.