Quick Comparison
| Ashwagandha | Zinc | |
|---|---|---|
| Half-Life | 6-12 hours (withanolides) | Tissue zinc turns over over weeks |
| 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: 15-30 mg elemental zinc daily. Do not exceed 40 mg daily long-term (can cause copper depletion). Zinc picolinate, zinc bisglycinate, and zinc carnosine are well-absorbed forms. Zinc oxide is poorly absorbed. Take with food to reduce nausea. If supplementing >15 mg daily, add 1-2 mg copper. |
| Administration | Oral (capsules, powder). Standardized extracts (KSM-66 or Sensoril) are preferred over raw root powder for consistent dosing. | Oral (capsules, tablets, lozenges). Take with food. Zinc picolinate or bisglycinate for best absorption. |
| Research Papers | 9 papers | 9 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.
Zinc
Zinc is released from synaptic vesicles (via ZnT3 transporter) during neurotransmission from glutamatergic mossy fiber and Schaffer collateral terminals. It modulates NMDA receptors — at high concentrations zinc blocks the channel at a distinct site from Mg2+, while at low concentrations it potentiates via the GluN2A subunit. Zinc modulates GABA-A receptors (positive allosteric at alpha1, negative at alpha2/3) and glycine receptors. It is required for BDNF synthesis (zinc finger transcription factors) and TrkB signaling. Zinc-dependent enzymes include carbonic anhydrase (CAII, pH regulation), Cu/Zn superoxide dismutase (SOD1, antioxidant defense), and matrix metalloproteinases (synaptic remodeling). In the hippocampus, zinc modulates long-term potentiation (LTP) via CaMKII and MAPK/ERK pathways — the cellular basis of memory formation. Zinc also regulates presynaptic vesicle release.
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.
Zinc
Common
Nausea on empty stomach, metallic taste.
Serious
Long-term high-dose use (>40 mg daily) depletes copper, causing anemia and neurological problems.
Rare
Headache, diarrhea, reduced immune function (paradoxically) at very high doses.
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.
Zinc →
An essential trace mineral concentrated in the brain's hippocampus, where it plays a critical role in synaptic transmission and memory formation. Zinc modulates NMDA and GABA receptors, supports BDNF expression, and is required for proper neurotransmitter release. Deficiency is common (estimated 17-25% of the global population) and directly impairs memory, attention, and mood.