Theanine and cancer: A systematic review of the literature

Phytother Res. 2021 Sep;35(9):4782-4794. doi: 10.1002/ptr.7110. Epub 2021 Apr 23.


A growing literature indicates several health benefits of theanine, a major nonprotein derivative amino acid special to tea, and a nonedible mushroom. This study aimed to systematically review the scientific evidence regarding the anticarcinogen and anticancer effects of natural theanine. A systematic search for the relevant articles published until January 2021 on MEDLINE, Scopus, and Web of Knowledge was conducted. Out of 377 initial records, 14 in vitro, ex vivo, and in vivo studies met our inclusion criteria. Most of the included in vitro and ex vivo studies reported beneficial effects of theanine on the proliferation, apoptosis, metastasis, migration, and invasion in various cancer cell lines. The in vivo studies also supported the potential impacts of theanine on cancer incidence or progression. Theanine exerted its anticancer function by inhibiting EGFR, VEGFR, Met, and Akt/mTOR, JAK2/STAT3, and ERK/NFκB pathways, as well as activating the intrinsic apoptosis pathway and caspase-independent programmed cell death. In conclusion, the results indicated moderate apoptotic, antimetastatic, antimigration, and anti-invasion effects, along with the mild antiproliferative influence of theanine on cancer. Further studies are necessary to ascertain the effectiveness of theanine on the prevention and suppression of cancer and shed light upon the attributable mechanisms in the in vivo condition.

Keywords: Theanine; apoptosis; cancer; proliferation; systematic review; γ-Glutamilethylamid.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Glutamates* / pharmacology
  • Humans
  • Neoplasms* / drug therapy
  • Signal Transduction / drug effects*
  • Tea


  • Glutamates
  • Tea
  • theanine