Tryptophan

Category: amino-acid

Aliases: Trp, W, L-Tryptophan

Pharmacological Mechanism

Serotonin + melatonin pathway: Trp → 5 htp (tryptophan hydroxylase) → serotonin (see serotonin melatonin axis) (AADC) → melatonin. Parallel kynurenine tryptophan pathway (>95% of Trp flux; inflammation shifts toward quinolinate / NAD⁺ at the expense of serotonin). NAD⁺ de-novo biosynthesis from kynurenine.

Half-Life (t½)

PO: 2h

Dosing Guidelines

• PO: Typical 0.667 g (Range: 0.5–1 g)

Target Organ Systems

• nervous
• endocrine
• immune-hematologic

Interactions

• 5-HTP (synergistic): 5-HTP is downstream of Trp (skips tryptophan hydroxylase) — feeds serotonin pool more directly.
• Serotonin (synergistic): Upstream AA precursor.

Pathways It Modulates

• Kynurenine pathway (substrate) — KP rate-limiting substrate (Trp depletion = pathway throughput limit)
• Tryptophan → serotonin → melatonin (substrate) — TPH step

Chemical Identifiers

• PubChem CID: 6305
• Formula: C11H12N2O2
• Molecular weight: 204.23 g/mol
• InChIKey: QIVBCDIJIAJPQS-VIFPVBQESA-N
• SMILES: C1=CC=C2C(=C1)C(=CN2)C[C@@H](C(=O)O)N

References

• PMID 10837313
• PMID 6805013