Amino AcidsL-Theanine

L-Theanine inhibits neuroblastoma cell proliferation via uptake through Slc38a1

L-Theanine inhibited proliferation of NSC-34 mouse motor neuron-like hybrid cells most effectively among neural cell lines tested. This inhibition was completely alleviated by co-administration of ฮฑ-(methylamino) isobutyric acid or leucine, suggesting theanine uptake occurs via Slc38a1 and excretion via Slc7a5. The inhibition persisted even without glutamine and did not correlate with mTOR phosphorylation changes.

Last updated: Jul 8, 2026โ€ข0 RCTsโ€ข๐Ÿ“– Read as article โ†’

Evidence Score

Evidence Score24/100
Human RCTโ˜†โ˜†โ˜†โ˜†โ˜†
Meta-analysisโ˜†โ˜†โ˜†โ˜†โ˜†
Mechanismโ˜…โ˜…โ˜…โ˜…โ˜…
Safetyโ˜…โ˜…โ˜…โ˜…โ˜†
Confidencelow

Study Evidence

Study 1. L-Theanine Uptake via Solute Carrier Family 38 Member 1 Inhibits Neuroblastoma Cell Growth.

observational

Kawada K, Matsushima Y, Nakamura R, Nishio M, Watanabe Y, Araki S, Sudo T, Yoshikawa S, Shibata M, Kinjo T, Uno K, Higashiura Y, Yamamuro A, Ishimaru Y, Yoshioka Y, Maeda S, Kuramoto N ยท Neurochemical research (2025)

Participants: N/A
Duration: N/A
Intervention: L-Theanine (L-gamma-glutamylethylamide) treatment on neural cell lines
Outcome: Proliferation inhibition of NSC-34 cells
Effect Size: N/A
Population: NSC-34 mouse motor neuron-like hybrid cells and other neural cell lines (in vitro)

Result:

PubMed: 41410739DOI: 10.1007/s11064-025-04635-0

Mechanism Graph

Theanine is taken up into cells via solute carrier family 38 member 1 (Slc38a1)
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Theanine is excreted from cells via solute carrier family 7 member 5 (Slc7a5)
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Intracellular theanine inhibits cell proliferation through an unclear mechanism independent of glutamine availability and mTOR signaling
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Result: Theanine inhibits proliferation of neural cells with abnormally proliferating Slc38a1, i.e., neuroblastoma

Limitations

  • โš The molecular mechanism of theanine's antiproliferative effect after cellular uptake remains unclear
  • โš Study was conducted only in vitro using mouse cell lines, not in human subjects or in vivo models

Frequently Asked Questions

What is the main finding of this study?โ–ผ

L-Theanine inhibits the proliferation of neuroblastoma cells by entering cells through the Slc38a1 transporter, though the exact intracellular mechanism is unknown.

Does L-Theanine affect normal neural cells?โ–ผ

The study focused on neural cell lines, particularly NSC-34 mouse motor neuron-like hybrid cells, and found theanine most effectively inhibited their proliferation compared to other neural cells tested.

How does L-Theanine enter cells?โ–ผ

L-Theanine uptake occurs via the glutamine transporter Slc38a1, and excretion occurs via the glutamine/leucine exchanger Slc7a5.

Is this study relevant to human sleep?โ–ผ

The abstract mentions theanine's known effects on alleviating stress and maintaining natural sleep, but this study specifically investigates its cancer-suppressing effect on neuroblastoma cells, not sleep.

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References

  1. 1.Kawada K, Matsushima Y, Nakamura R, Nishio M, Watanabe Y, Araki S, Sudo T, Yoshikawa S, Shibata M, Kinjo T, Uno K, Higashiura Y, Yamamuro A, Ishimaru Y, Yoshioka Y, Maeda S, Kuramoto N. "L-Theanine Uptake via Solute Carrier Family 38 Member 1 Inhibits Neuroblastoma Cell Growth.." Neurochemical research, 2025. PMID: 41410739 DOI: 10.1007/s11064-025-04635-0
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.