L-Theanine vs Ashwagandha
Both graded for Sleep & Stress
Both are Grade B for the shared sleep-stress goal, so the choice is about mechanism and timing, not evidence tier. Reach for L-theanine when you want acute, in-the-moment calm without sedation or next-day fog — its RCTs show reduced perceived stress and (paired with caffeine) sharper attention, and it has the cleaner safety record, with no significant adverse effects up to 400 mg/day and only a mild blood-pressure caveat. Reach for ashwagandha when the problem is sustained stress load or poor sleep in a stressed/anxious person: it's taken daily over 8-12 weeks and has direct RCT data on lowering cortisol (a 28% drop in one 64-person KSM-66 trial) plus bonus signals for strength and VO2 max — but its trials are small, short, and often manufacturer-funded, and it carries more caveats (thyroid effects, avoid in pregnancy, limited long-term safety). Neither is clearly better-evidenced; pick L-theanine for fast, low-risk situational calm, ashwagandha for a multi-week reset of chronic stress and cortisol.
L-Theanine
A calming amino acid from tea with solid RCT evidence for reducing stress and improving focused attention — without causing drowsiness.
Promotes relaxation and reduces perceived stress without sedation
100-400 mg/day; 200 mg is the most common dose in clinical trials. Often taken 1-2 times daily.
Sleep & Stress, Brain & Cognitive
Ashwagandha
An adaptogen with real RCT data for stress and cortisol reduction — not Grade A because trial sizes are small and long-term data is limited.
Reduces perceived stress and cortisol levels
300-600 mg/day of a standardized root extract (typically standardized to 5% or higher withanolides). KSM-66 and Sensoril are the most-studied branded extracts.
Sleep & Stress, Energy & Fatigue, Muscle & Athletic Performance
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