Ifunguro ry’icyayi kibisi ni inyunganiramirire ikunzwe cyane kandi ikunzwe cyane mu myaka ya vuba aha bitewe n’inyungu nyinshi ifite ku buzima. Ifunguro ry’icyayi kibisi rimaze ibinyejana byinshi rikoreshwa mu buvuzi gakondo.

Igice gikora cy’icyayi kibisi ni polyphenol y’icyayi, ni antioxydant ikomeye ikekwaho gutanga inyungu nyinshi ku buzima.

Zimwe mu nyungu zizwi cyane z’icyayi kibisi ku buzima harimo ubushobozi bwo kunoza imikorere y’ubwonko, kongera imikorere y’umubiri, no kugabanya ibyago byo kurwara kanseri imwe n’imwe. Bishobora kandi gufasha uruhu n’umusatsi kugira ubuzima bwiza, gukumira imyobo no guteza imbere amenyo meza, no gushyigikira ubuzima bw’umutima.

Imwe mu nyungu z'ingenzi z'icyayi kibisi ni uko ari isoko karemano ya kafeyine, ishobora gufasha kongera imbaraga no kwibanda ku kintu runaka. Ariko, bitandukanye n'izindi soko za kafeyine, icyayi kibisi gikungahaye kuri L-theanine, aside amine ifasha mu kuruhuka no kugabanya imihangayiko n'ihungabana.