L-Theanine is an amino acid found primarily in tea leaves that readily crosses the blood-brain barrier. It increases alpha brain wave activity, promoting a state of relaxed alertness, and modulates neurotransmitters like GABA and serotonin. Its primary healthspan relevance lies in its ability to mitigate chronic stress and improve sleep quality, both of which are foundational for maintaining long-term neurological health and metabolic function.
Verdict
A safe, effective tool for managing stress and improving sleep quality.
HEALTHSPAN IMPACT
Moderate
RISK LEVEL
Low
EVIDENCE GRADE
A
MONTHLY COST
$5 - $30
Protocol
- Take 100-200 mg once or twice daily, often with caffeine to mitigate jitters.
- Consider 200-400 mg about 30-60 minutes before bedtime to support sleep quality.
Flags
- High doses may cause mild headaches or dizziness in sensitive individuals.