Per gram numbers
Published assays and producer disclosures from Ippodo and Mizuba converge on roughly 34 milligrams of caffeine per gram of matcha powder. L-theanine in shaded tencha-based matcha typically lands around 20 to 30 milligrams per gram, depending on harvest and shading.
Per typical serving
A 2 gram usucha therefore delivers around 60 to 70 milligrams of caffeine and roughly 40 to 60 milligrams of L-theanine. Koicha at 4 grams roughly doubles both. These numbers are usable estimates, not exact figures, since they vary by cultivar, harvest, and shading.
What that means in practice
The caffeine load of a single usucha sits between a strong cup of black tea and a small cup of drip coffee. L-theanine and caffeine in tea have been studied together in cognitive research, but this app does not make health, medical, or treatment claims. Pay attention to your own tolerance and timing.