L-theanine is an amino acid predominantly found in green tea, known for its numerous health benefits, including stress reduction, cognitive enhancement, and immune support.

Benefits and Uses of L-theanine

1. Stress and Anxiety Reduction:
   Several systematic reviews have shown that L-theanine helps manage stress and anxiety. Supplementing with 200-400 mg/day of L-theanine can significantly reduce stress and anxiety in stressful conditions¹².

2. Mood and Cognitive Function:
   L-theanine enhances mood and cognitive functions, such as memory and attention, by increasing alpha brainwave activity, which promotes relaxation without drowsiness³. It also improves depressive symptoms, sleep quality, and cognitive impairments in patients with major depressive disorder⁴.

3. Neuroprotective Effects:
   L-theanine possesses neuroprotective properties, aiding in the mitigation of neurodegenerative conditions and improving cognitive function in middle-aged and older subjects⁵.

4. Cardiovascular and Metabolic Health:
   The compound has been shown to have cardiovascular protective effects by inhibiting blood pressure increases under stress, and it also plays a role in metabolic regulation⁶.

5. Immune System Support:
   L-theanine enhances immune functions, which can help in reducing the immunosuppressive effects of stress and strenuous exercise, and it may lower the risk of colds and influenza⁷.

Summary of Key Sources

• Systematic Review on Anxiety and Stress: L-theanine supplementation (200-400 mg/day) was found effective in reducing stress and anxiety in stressful conditions¹.
• Open-label Study on Major Depressive Disorder: Chronic administration of L-theanine exhibited multiple beneficial effects on depressive symptoms, anxiety, and sleep disturbance⁴.
• Neuroprotective Review: Highlighted the antioxidant, anti-inflammatory, and neuroprotective properties of L-theanine⁶.
• Immune Function Review: Documented L-theanine's role in immunoregulation and protection against pathogens⁷.

For more detailed product recommendations or specific brands containing L-theanine, feel free to ask!

Footnotes

1. Examine.com: Theanine Supplement Benefits ↩ ↩²

2. PubMed: The Effects of Green Tea Amino Acid L-Theanine Consumption on Stress and Anxiety ↩

3. PubMed: L-theanine and Its Effect on Mental State ↩

4. PubMed: Effects of L-theanine in Major Depressive Disorder ↩ ↩²

5. PubMed: Effects of L-Theanine on Cognitive Function ↩

6. NCBI: L-Theanine: A Unique Functional Amino Acid ↩ ↩²

7. NCBI: L-Theanine and Immunity: A Review ↩ ↩²