L-Theanine
L-Theanine
Last reviewed: June 2026 · Medically reviewed by a licensed pharmacist
What it does
L-theanine is the amino acid in green tea behind that calm but alert feeling. It promotes relaxation without making you drowsy, and pairs especially well with caffeine, smoothing out the jitters while keeping the focus. Trials link it to lower perceived stress and better attention, which is why it's a favorite for deep-work and wind-down routines alike.
The science
L-Theanine promotes alpha-wave brain activity, creating calm focus without sedation. Often combined with caffeine to smooth stimulation and reduce jitteriness.
Most relevant for
Focus without jitters, calmer energy, and pairing with coffee.
Key references
General wellness information, not medical advice. Consult your healthcare provider before starting any supplement. Build your personalized stack →