L-Theanine
L-theanine is a non-protein amino acid found primarily in tea leaves (Camellia sinensis), particularly green tea. It is valued for its ability to promote a state of calm alertness without causing sedation, making it one of the few compounds that can reduce stress while maintaining mental clarity. It readily crosses the blood-brain barrier, typically producing noticeable effects within 30-60 minutes of ingestion.
Expert Evidence
24 references from 3 experts
“Theanine, provided it's safe for you, can be taken 100 or 200 milligrams about 30 or 60 minutes before sleep. It can enhance the transition to sleep and depth of sleep. It increases GABA, and has also been shown for people that are chronically stressed to significantly increase relaxation.”
Tools for Managing Stress & Anxiety | Huberman Lab Essentials
30:1021 references in 11 episodes from 2021–2025
Huberman regularly takes and strongly recommends L-theanine as part of his sleep stack (with magnesium threonate and apigenin), and also endorses it for offsetting caffeine jitteriness and reducing anxiety. He consistently warns that people prone to vivid dreams, sleepwalking, or night terrors should avoid it or reduce the dose.
Consumption
Huberman takes 100-200mg of theanine 30-60 minutes before sleep as part of his nightly sleep stack.
Benefits
Theanine enhances sleep quality, depth, and duration by increasing GABA and activating chloride channels. It also significantly reduces anxiety and stress in chronically stressed individuals, can help offset caffeine jitteriness, and may reduce depression at 200-400mg doses taken 1-3 times daily.
Best Practices
For sleep, take 100-200mg of theanine 30-60 minutes before bed, ideally combined with magnesium threonate and apigenin. To offset caffeine jitteriness, 200-400mg is effective; doses up to 900mg/day have been shown safe but may cause excessive sleepiness.
Cautions
People who experience vivid dreams, sleepwalking, or night terrors should avoid theanine or reduce to 100mg, as it intensifies dream vividness and emotional content.
“Combining roughly 100 to 200 milligrams of L-theanine with about 100 to 150 milligrams of caffeine significantly improves cognitive performance. People experience enhanced sustained attention, faster reaction times, better accuracy on demanding cognitive tasks, and notably fewer feelings of anxiety or jitters.”
How To Use Coffee To Live Longer (Full Guide & Research)
46:102 references in 1 episode from 2025
Rhonda Patrick highlights L-theanine's mechanism of increasing GABA and glycine signaling to promote calm, attentive alpha brain wave states without sedation. She specifically recommends combining 100–200 mg of L-theanine with 100–150 mg of caffeine for enhanced sustained attention, faster reaction times, and reduced anxiety. No evidence of personal use, cautions, or standalone dosing guidance is provided.
“If you've had issues with sleep or stress long term, then there are interesting things like theanine and ashwagandha KSM-66. They seem to improve stress and also cognitive function in those settings.”
Dr. Tommy Wood: Enhancing Brain Performance & Preventing Dementia
32:571 reference in 1 episode
Galpin mentions L-theanine as a potentially useful supplement for people with chronic sleep or stress issues, grouping it with ashwagandha KSM-66 as options that may improve stress and cognitive function. He does not indicate personal use, provide specific dosing guidance, or discuss any cautions.
Side Effects
- Unusually vivid dreams
- Possible worsening of sleepwalking or night terrors
- Mild headache at high doses
- Slight drop in blood pressure
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