Ashwagandha (KSM-66) vs Shilajit

Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.

✅ Stacking Partners — These compounds are commonly used together and may have synergistic effects.
Ashwagandha (KSM-66)Shilajit
CategoryAdaptogensAdaptogens
Standard Dose600mg KSM-66 daily (300mg 2x/day)250-500mg purified shilajit daily (standardized to >50% fulvic acid)
TimingMorning and evening with meals. Evening dose supports sleep quality via cortisol reduction.Morning with warm water or milk (traditional Ayurvedic method). Can be split AM/PM.
Cycle DurationCycle 8-12 weeks on, 2-4 weeks off (to prevent adaptogenic tolerance)Cycle 8-12 weeks on, 2-4 weeks off
Evidence Levelstrong_humanmoderate_human

Mechanism

Ashwagandha's primary bioactives are withanolides (particularly withaferin A and withanolide D). KSM-66 is a full-spectrum root extract standardized to >5% withanolides. It modulates the HPA axis by reducing cortisol output (20-30% reduction in trials), likely through GABAergic activity (withanolides are GABA-mimetic at GABA-A receptors) and by normalizing cortisol receptor (GR) sensitivity. It also inhibits the NMDA-induced neurotoxicity pathway, enhances DHEA-S production, promotes thyroid function (increases T4 to T3 conversion), upregulates antioxidant enzymes (SOD, catalase, glutathione peroxidase), and has demonstrated sirtuin-activating properties.

Standard Dosing

600mg KSM-66 daily (300mg 2x/day)

Timing

Morning and evening with meals. Evening dose supports sleep quality via cortisol reduction.

Cycle Duration

Cycle 8-12 weeks on, 2-4 weeks off (to prevent adaptogenic tolerance)

Side Effects

  • Drowsiness
  • GI upset
  • Thyroid hormone elevation
  • Rare: liver injury (case reports, mainly with combination products)
  • Vivid dreams
  • Increased appetite

Contraindications

  • Hyperthyroidism or Graves' disease
  • Autoimmune conditions (immunostimulatory)
  • Pregnancy (traditionally considered emmenagogue/abortifacient)
  • Nightshade sensitivity (Solanaceae family)

Best Stacking Partners

Rhodiola RoseaMagnesiumL-TheanineTongkat Ali
B

Shilajit

Adaptogens

Mechanism

Shilajit is a mineral-rich exudate containing fulvic acid (60-80%), dibenzo-alpha-pyrones (DBPs), and over 85 minerals in ionic form. Fulvic acid acts as an electron shuttle in mitochondrial electron transport, enhancing CoQ10 function and ATP production. DBPs protect CoQ10 from oxidation, extending its functional half-life. Shilajit increases total and free testosterone by stimulating steroidogenesis and reducing SHBG. It also enhances mitochondrial membrane potential, acts as a potent antioxidant (fulvic acid neutralizes free radicals), and improves mineral absorption by forming bioavailable fulvic acid-mineral complexes.

Standard Dosing

250-500mg purified shilajit daily (standardized to >50% fulvic acid)

Timing

Morning with warm water or milk (traditional Ayurvedic method). Can be split AM/PM.

Cycle Duration

Cycle 8-12 weeks on, 2-4 weeks off

Side Effects

  • GI discomfort
  • Dizziness
  • Increased heart rate (rare)
  • Allergic reaction (rare)
  • Metallic taste

Contraindications

  • Hemochromatosis (iron content)
  • Active gout (may increase uric acid)
  • Sickle cell disease
  • Thalassemia

Best Stacking Partners

CoQ10 (synergistic mitochondrial support)AshwagandhaTongkat AliMagnesium

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