Supplement Library

Grounded in published research. Not medical advice.

L-Theanine

L-theanine is an amino acid listed in PubChem as C7H14N2O3 with a molecular weight of 174.20. NIH ODS has no L-theanine fact sheet, and NCCIH has no L-theanine monograph. NCCIH's green tea page names Camellia sinensis and does not name L-theanine.

L-theanine is a small amino acid. PubChem lists it as CID 439378, molecular formula C7H14N2O3, molecular weight 174.20, IUPAC name (2S)-2-amino-5-(ethylamino)-5-oxopentanoic acid. There is no NIH ODS fact sheet and no NCCIH monograph for L-theanine.

What is L-theanine?

PubChem’s compound record identifies L-theanine by formula, mass, and IUPAC name. That is a chemistry record, not a dosing monograph.

Tea is the food most often mentioned next to theanine in popular writing. NCCIH’s green tea page, fetched the same day, describes Camellia sinensis and its catechins and caffeine. It does not name L-theanine. This entry does not move tea-page sentences onto theanine.

Is there an ODS or NCCIH L-theanine monograph?

No. On 18 August 2026 the ODS health-professional path for Theanine returned 404. The ODS A–Z fact sheet list has no Theanine entry. NCCIH has a green tea page and no L-theanine page.

Without those monographs, this site does not invent typical milligram ranges, onset times, or brain-mechanism claims.

Why do people pair L-theanine with caffeine?

That pairing is a common product and search pattern. It is not described on an ODS or NCCIH theanine page, because those pages do not exist. NCCIH’s green tea page discusses caffeine as a constituent of the tea plant. It does not describe a theanine-plus-caffeine protocol.

What can this page honestly say?

It can name the compound from PubChem. It can state the monograph gap. It cannot fill that gap with recalled trial doses or with tea-page findings that do not mention theanine.

Sources

  1. L-Theanine compound record. PubChem, National Library of Medicine. https://pubchem.ncbi.nlm.nih.gov/compound/Theanine Accessed 2026-08-18.
  2. Green Tea: Usefulness and Safety. National Center for Complementary and Integrative Health. https://www.nccih.nih.gov/health/green-tea Accessed 2026-08-18.