Theanine is found in tea and has been known for some 80 years
L-theanine is the most common form of theanine that is found naturally in tea.
Theanine had been tried for many conditions, for cognitive disorders and also as a sedative and for ADD etc. I seem to have a calming effect on some people who get overexcited by their cup[s] of coffee .
If this is the case, and you like your cup of coffee then you may try to take theanine.
Hel [cardamom] maybe a simpler solution [more available] and is very well known in Arabic tradition, added as seeds [pods] to the coffee.