L-theanine
Amino acid from green tea that promotes calm without sedation.
Why
L-theanine increases alpha brain wave activity associated with relaxed alertness. Often paired with magnesium for sleep, or with caffeine to smooth its anxiogenic effects. A 2020 systematic review on stress and anxiety, plus several small RCTs on sleep, support modest effects at 200-400mg/day.
How it works
Crosses the blood-brain barrier and promotes alpha wave activity; modulates glutamate and GABA balance toward parasympathetic tone.
Expected onset · Acute (30–60 min) effect; cumulative gains by 4 weeks
How to take
Dosage
100–200 mg, can be combined with magnesium glycinate at bedtime.
Timing
Evening, or pair with morning caffeine
On the label
Look for Suntheanine® or 99%+ pure L-theanine.
Safety
Evidence
Williams 2020 Plant Foods Hum Nutr systematic review (9 trials) supports 200–400 mg/day L-theanine for reducing stress and anxiety under stressful conditions; the authors flag that effect sizes are modest and trial quality variable. Hidese 2019 Nutrients (n=30, 4-week crossover): 200 mg/day improved stress-related symptoms and cognition vs placebo.
Where to get it
Shop L-theanine on AmazonSponsored · As an Amazon Associate, Healicus earns from qualifying purchases.