Back to Library
Lth7.5

L-Theanine

L-Theanine

An amino acid from tea that promotes calm, focused alertness without drowsiness by boosting alpha brain waves.

mentalsleepfocuscalmanxietysleep
7.5/10
100+ studies
Evidence
high
Safety
100-200mg
Dose
1-2 weeks
Time to Effect
Suntheanine® capsules or powder
Best Form

L-Theanine is a unique amino acid found primarily in tea leaves. It crosses the blood-brain barrier and promotes alpha brain wave activity, creating a state of calm alertness. It's particularly effective for reducing anxiety and jitteriness from caffeine while maintaining focus.

Mechanisms of Action

🧠
Alpha Brain Waves

Increases alpha wave activity associated with relaxed alertness

⚖️
GABA/Glutamate Balance

Modulates excitatory and inhibitory neurotransmitters

😊
Dopamine & Serotonin

Supports feel-good neurotransmitter levels

Recommended Dose

100-200mg

50mg400mg

Optimal Timing

  • Morning with coffee for focus
  • Evening for relaxation
  • As needed for stress

Can be taken without food

Best Form

Suntheanine® capsules or powder

Alternatives: Generic L-theanine, Green tea (lower dose)

Suntheanine is the most studied form. A cup of green tea contains ~20-30mg L-theanine. Capsules provide consistent dosing.

Duration

Minimum: 1 weeks

Optimal: 2 weeks

Cycling: Not required

Note: Works within 30-60 minutes. Can be taken multiple times daily. Popular combination: 100mg L-theanine with each cup of coffee.

🎯
Calm Focus

Relaxed but alert mental state

30-60 minutes
85% of users notice thispositive
Reduced Caffeine Jitters

Smooths out caffeine's stimulating effects

30-60 minutes
90% of users notice thispositive
😌
Mental Relaxation

Reduced mental tension and racing thoughts

30-60 minutes
80% of users notice thispositive
🔍
Subtle Effects

Effects are gentle; may be subtle for some

Varies
25% of users notice thisneutral
High SafetyMax safe dose: Up to 400mg/day used in studies without adverse effects; higher doses possible but less studied
🟢
Pregnant/nursing

Limited data; green tea is generally considered safe but supplements should be discussed with doctor

🟡
Children

Some evidence for ADHD; consult pediatrician for dosing

Who Should NOT Take This

  • None known at recommended doses

Drug Interactions

Blood pressure medicationsmild

May have additive blood pressure lowering effects

Stimulantsmild

May modify stimulant effects (often desirable)

Possible Side Effects

Headacherare

Tip: Reduce dose

Drowsinessrare

Tip: More common at higher doses or in sensitive individuals

Warnings

  • Very safe with excellent tolerability
  • Effects are subtle - not a strong sedative
  • Quality varies between brands
rctn=35
DOI

Nobre AC et al.Asia Pacific Journal of Clinical Nutrition (2008)

L-theanine significantly increases activity in the alpha frequency band, indicating that it relaxes the mind without inducing drowsiness.
Key Findings:
  • Increased alpha brain wave activity
  • Effects seen within 30-40 minutes
  • Relaxation without sedation
rctn=27
DOI

Owen GN et al.Nutritional Neuroscience (2008)

The combination of L-theanine and caffeine improved both speed and accuracy of performance on attention-switching tasks.
Key Findings:
  • Improved attention and task switching
  • Better accuracy on cognitive tasks
  • L-theanine reduces caffeine's negative effects
rctn=30
DOI

Hidese S et al.Nutrients (2019)

L-theanine administration resulted in reductions in stress-related symptoms and improvements in cognitive function.
Key Findings:
  • Reduced stress and anxiety
  • Improved sleep quality
  • Enhanced cognitive performance

AI-discovered studies. Verify citations before citing.

Effects of L-theanine on anxiety

DOI

Hidese S et al. • Nutrients (2019)

L-theanine administration resulted in reductions in stress-related symptoms and improvements in cognitive function.

  • Reduced stress and anxiety
  • Improved sleep quality
  • Enhanced cognitive performance
rctn=30high confidence

L-theanine, a natural constituent in tea, and its effect on mental state

DOI

Nobre AC et al. • Asia Pacific Journal of Clinical Nutrition (2008)

L-theanine significantly increases activity in the alpha frequency band, indicating that it relaxes the mind without inducing drowsiness.

  • Increased alpha brain wave activity
  • Effects seen within 30-40 minutes
  • Relaxation without sedation
rctn=35high confidence

The combination of L-theanine and caffeine improves cognitive performance

DOI

Owen GN et al. • Nutritional Neuroscience (2008)

The combination of L-theanine and caffeine improved both speed and accuracy of performance on attention-switching tasks.

  • Improved attention and task switching
  • Better accuracy on cognitive tasks
  • L-theanine reduces caffeine's negative effects
rctn=27high confidence