L-Theanine

Effects and Benefits

Core Identification

Common Names:
- L-Theanine
- Theanine
- N-ethyl-L-glutamine
- Gamma-glutamylethylamide

Latin Name: N/A (isolated compound from Camellia sinensis)

Category: Amino Acid

Uses

Traditional Uses

• Tea consumption for relaxation and mental clarity - East Asian cultures, centuries
• Japanese food additive in candy, beverages, and foods - Japan, decades
• Traditional tea ceremonies emphasizing calming yet alert states - East Asia, centuries

Modern Uses

• Stress and Anxiety Reduction - Promotes relaxation without sedation | Research quality: Strong
• Key findings: At 200mg, L-theanine improved both subjective and objective markers of stress including heart rate, alpha-wave activity, and immune response; increases alpha waves in brain similar to GABA but with milder effect

• Source citations: Moyad - The Supplement Handbook

• Sleep Support - Helps with stress-related insomnia | Research quality: Moderate

• Key findings: 100-200mg taken 30-60 minutes before bedtime can improve sleep quality, particularly when stress is the underlying cause; works by increasing GABA, serotonin, and dopamine in the brain

• Source citations: Moyad - The Supplement Handbook; Brighten - Beyond the Pill

• ADHD Support in Children - May improve sleep and reduce daytime symptoms | Research quality: Preliminary

• Key findings: 100-200mg at breakfast and after school improved sleep in boys ages 8-12; better sleep may reduce ADHD symptoms the following day

• Source citations: Moyad - The Supplement Handbook

• Cognitive Enhancement with Caffeine - Counteracts caffeine jitteriness while maintaining focus | Research quality: Moderate

• Key findings: L-theanine naturally counteracts the stimulatory effects of caffeine; promotes calm alertness rather than sedation

• Source citations: Moyad - The Supplement Handbook; Brighten - Beyond the Pill

• Blood Pressure Support - May help stabilize stress-related blood pressure | Research quality: Preliminary

• Key findings: 100-200mg daily may help stabilize or lower blood pressure by several points through stress reduction mechanisms

• Source citations: Moyad - The Supplement Handbook

• Immune Support - Enhanced vaccination response when combined with L-cysteine | Research quality: Preliminary

• Key findings: Nursing home residents taking L-cysteine and L-theanine two weeks before flu vaccination showed improved immune response
• Source citations: Balch - Prescription for Herbal Healing

Active Compounds

Primary Active Ingredients:
- L-Theanine (N-ethyl-L-glutamine) - The primary bioactive compound; crosses blood-brain barrier to modulate neurotransmitters and brain wave activity
- Gamma-glutamylethylamide - Alternate chemical name for the same compound; structurally related to glutamate and GABA

Dosage Information

Standard Dosage:
- Form: Capsule, tablet, or powder
- Amount: 100-200 mg per day
- Frequency: Once daily or divided into two doses

Therapeutic Dosage:
- Form: Capsule or tablet
- Amount: 200-250 mg per day (shows more consistent effects)
- Purpose: For stress, anxiety, or sleep support
- Duration: Can be used ongoing; no established cycling requirement

Pediatric Dosage (ADHD support):
- Form: Capsule or powder
- Amount: 100-200 mg
- Frequency: At breakfast and again after school
- Note: Consult healthcare provider before use in children

Maximum Safe Dosage:
- Daily maximum: Not established; doses up to 400mg daily used safely in studies
- Warning threshold: No established upper limit, but start low and increase gradually

Bioavailability Notes:
- Well absorbed orally
- Effects typically felt within 30 minutes
- Duration of effects approximately 2 hours
- Can be taken with or without food
- Suntheanine (patented form) has the most clinical research

How to Take It

Timing:
- For stress/anxiety: Any time of day; can divide dose morning and afternoon
- For sleep: 30-60 minutes before bedtime
- For ADHD support: Breakfast and after school
- For caffeine modulation: Take with coffee or caffeinated beverages
- With or without food - both are acceptable

Synergies - What It Works Well With

Complementary Supplements:
1. Caffeine - L-theanine counteracts jitteriness while caffeine provides energy | Combined effect: Calm, focused alertness without overstimulation; the combination found naturally in tea
2. GABA - Both support relaxation through different mechanisms | Combined effect: Enhanced calming effect; GABA may be more potent while L-theanine is milder and safer
3. L-Cysteine - Immune-enhancing combination | Combined effect: Improved vaccination response and immune function
4. Magnesium - Both support nervous system relaxation | Combined effect: Enhanced stress relief and sleep support
5. Passionflower - Complementary calming herbs/supplements | Combined effect: May provide broader anxiety support

Avoidance - What NOT to Combine With

Supplement Interactions:
1. High-dose sedative herbs (Valerian, Kava) - May have additive sedative effects | Potential consequence: Excessive drowsiness; use caution when combining

Drug Interactions:
1. Blood Pressure Medications - May add to hypotensive effect | Potential consequence: Blood pressure may drop too low | Severity level: Mild
2. Sedative Medications (benzodiazepines, sleep aids) - May increase sedation | Potential consequence: Excessive drowsiness | Severity level: Moderate
3. Stimulant Medications - L-theanine may counteract some stimulant effects | Potential consequence: Reduced medication efficacy | Severity level: Mild

Food Interactions:
- No known significant food interactions
- Naturally found in tea; safe to consume tea while supplementing

Safety Information

Contraindications:
- No absolute contraindications established
- Use caution in those with very low blood pressure

Side Effects:
- Common: None reported at typical doses
- Rare: Headache, dizziness (uncommon)
- L-theanine has an excellent safety record

Long-Term Use:
- Considered safe for long-term use
- FDA designated as GRAS (Generally Recognized as Safe) since 2007
- Used as food additive in Japan for decades without safety concerns
- No tolerance or dependency issues documented

Special Precautions:
- Pregnancy/Lactation: Limited data; consult healthcare provider
- Children: Appears safe in children ages 8-12 at appropriate doses; consult healthcare provider
- Surgery: No specific precautions established; inform surgeon of all supplements

Primary Uses At-a-Glance

Primary: Stress and anxiety relief, sleep support (stress-related insomnia), calm focus (especially with caffeine)

Secondary: ADHD support in children, blood pressure stabilization, immune enhancement

Sources

Local Library:
- Moyad, Mark - The Supplement Handbook
- Brighten, Jolene - Beyond the Pill
- Balch, Phyllis - Prescription for Herbal Healing
- Mars, Brigitte - The Home Reference to Holistic Health and Healing
- Curtis, Susan - Neal's Yard Remedies
- Gladstar, Rosemary - Herbs for Long-Lasting Health
- Colbert, Don - Reversing Diabetes
- Harper-Jones, Miriam - The Holistic Home Apothecary
- Stewart, Martha - Living the Good Long Life

General Knowledge:
- First isolated from tea leaves in 1949; from mushrooms in early 1950s
- Suntheanine is the most researched patented form
- Approximately 20mg of L-theanine found naturally per cup of black tea
- Also found in guayusa plant and certain mushrooms (Boletus badius)