L-Theanine is an amino acid ingredient in green tea with a structural analogy to L-glutamine. L-Theanine accumulation consisted of at least two different components with Km values of 42.3 µM and 1.88 mM, and Vmax values of 3.92 and 104.2 nmol/h/mg protein, respectively. L-Theanine efficiently suppressed elevations of systemic blood pressure and brain 5-hydroxyindoles levels in spontaneous hypertensive rats.A prior intracerebroventricular injection of L-Theanine protected the hippocampal CA1 pyramidal neurons against delayed neuronal cell death in gerbils with bilateral forebrain global ischemia[3].
L-Theanine/L-茶氨酸 细胞实验
Cell Line
Concentration
Treated Time
Description
References
Tea plant seedlings
0.1, 1, 5 mM
14 days
Theanine inhibited lateral root development
Hortic Res. 2022 Dec 2;10(2):uhac267
Arabidopsis seedlings
0.01, 0.1, 1, 5 mM
2 days
Theanine inhibited lateral root development
Hortic Res. 2022 Dec 2;10(2):uhac267
B16F10 murine melanoma cells
0.6-3 mM
24 hours
To evaluate the effects of L-theanine on melanogenesis, results showed that L-theanine significantly reduced intracellular tyrosinase activity and melanin content.
Molecules. 2025 Feb 19;30(4):956
AML12 cells
1-4 mM
24 hours
Theanine significantly alleviated OA-induced steatosis in AML12 cells and reduced intracellular TG levels.
Nutr Metab (Lond). 2022 Apr 15;19(1):29
HepG2 cells
1-4 mM
24 hours
Theanine significantly alleviated OA-induced steatosis in HepG2 cells and reduced intracellular TG levels.
Nutr Metab (Lond). 2022 Apr 15;19(1):29
Rat primary chondrocytes
50, 100, 200 µM
24 hours
L-theanine dose-dependently decreased mRNA and protein levels of MMP-3 and MMP-13, as well as the expression of COX-2 and iNOS in IL-1β-stimulated chondrocytes, and reduced the secretion of PGE-2 and NO in the culture supernatant.
Nutrients. 2020 Jul 3;12(7):1988
Botrytis cinerea
5 mM
7 days
To evaluate the antifungal activity of theanine against Botrytis cinerea in vitro. Results showed that 5 mmol L−1 theanine treatment significantly inhibited the mycelial growth of B. cinerea, reducing the colony diameter by 18%.
Food Chem X. 2024 Aug 24;23:101772
L-Theanine/L-茶氨酸 动物实验
Species
Animal Model
Administration
Dosage
Frequency
Description
References
Zebrafish
Zebrafish larvae
Added to culture media
<2 mg/mL
48 hours
To evaluate the inhibitory effect of L-theanine on melanogenesis in zebrafish, results showed that L-theanine significantly reduced melanin production.
Molecules. 2025 Feb 19;30(4):956
Tea plant
Seedlings
Hydroponic solution
1 mM
14 days
Theanine inhibited lateral root development by modulating H2O2 accumulation
Hortic Res. 2022 Dec 2;10(2):uhac267
C57BL/6J mice
Myocardial ischemia-reperfusion injury model
Intraperitoneal injection
10 mg/kg
Once daily for seven days
Theanine attenuates myocardial ischemia-reperfusion injury by suppressing oxidative stress and apoptosis, partially through activation of the JAK2/STAT3 signaling pathway.
Mol Med. 2024 Jun 28;30(1):98
Male Sprague Dawley rats
Adolescent THC exposure model
Intraperitoneal injection
10 mg/kg
Twice daily from P35 to P45
L-theanine pretreatment before adolescent THC exposure is capable of preventing long-term, THC-induced dysregulation of both PFC and VTA DAergic activity states, a neuroprotective effect that persists into adulthood. In addition, pretreatment with L-theanine blocked THC-induced down-regulation of local GSK-3 (glycogen synthase kinase 3) and Akt signaling pathways directly in the PFC, two biomarkers previously associated with cannabis-related psychiatric risk and subcortical DAergic dysregulation. Finally, L-theanine powerfully blocked the development of both affective and cognitive abnormalities commonly associated with adolescent THC exposure, further demonstrating functional and long-term neuroprotective effects of L-theanine in the mesocorticolimbic system.
J Neurosci. 2021 Jan 27;41(4):739-750
C57BL/6 mice
IMQ-induced psoriasis like skin inflammation model
Topical application
10 mM or 100 mM
Twice per day for five consecutive days
Theanine significantly alleviated IMQ-induced psoriasis like skin inflammation, reducing epidermal thickness and inflammatory response
Front Pharmacol. 2021 Jul 26;12:719842
Tea plants (Camellia sinensis L.)
Salt stress model
Nutrient solution treatment
10 mM theanine
3 days
Theanine improves salt stress tolerance via modulating redox homeostasis in tea plants
Front Plant Sci. 2021 Oct 15;12:770398
C57BL/6 male mice
Acute alcoholic intestinal injury model
Oral
100, 200, and 400 mg/kg/day
Once daily for 28 days
Theanine mitigates acute alcoholic intestinal injury by activating the HIF-1 signaling pathway to regulate the TLR4/NF-κB/HIF-1α axis.
Nutrients. 2025 Feb 18;17(4):720
Mice
Healthy mice
Gavage
100, 300, 400 mg/kg/d
Once daily for 28 days
LTA supplementation not only affects serum alkaline phosphatase (AKP), total protein (TP), and urea nitrogen (BUN) levels, but it also upregulates the mRNA and protein expression of amino acid transporters (EAAT3, EAAT1, 4F2hc, y+LAT1, CAT1, ASCT2, and B0AT1), and activates the mTOR signaling pathway.
Nutrients. 2022 Dec 28;15(1):142
Mice
DdY mice
Drinking water
20 µg/mL
Continued for 6 months
Theanine intake significantly suppressed adrenal hypertrophy in the group-housed older mice and reduced the expression of holo-GR and Dnmt3a in the hippocampus, potentially reversing the repressed state of Npas4 transcription.
Int J Mol Sci. 2023 Feb 16;24(4):3983
Sprague-Dawley rats
Doxorubicin-induced ovarian toxicity model
Oral gavage
200 mg/kg and 400 mg/kg
Once daily for 3 days
To investigate the protective effects of theanine on doxorubicin-induced ovarian toxicity, results showed that theanine ameliorated ovarian damage by reducing oxidative stress, inflammation, and endoplasmic reticulum stress.
Food Sci Nutr. 2025 Apr 24;13(4):e70150
Spontaneously hypertensive rats
Spontaneously hypertensive rats
Oral
27 µg/mL
Free access to drinking, for 6 weeks
L-theanine contributes to the prevention of bladder dysfunctions by inhibiting chronic sympathetic hyperactivity and protecting bladder contractility
Metabolites. 2021 Nov 14;11(11):778
Wistar rats
Vincristine-induced neuropathy model
Intraperitoneal injection
30, 100, and 300 mg/kg/day
Once daily for 21 days
Theanine significantly alleviated vincristine-induced neuropathy, including hyperalgesia, allodynia, and nerve functional loss, through its antioxidative, calcium homeostasis, anti-inflammatory, anti-apoptotic, and neuroprotective properties.
Antioxidants (Basel). 2023 Mar 25;12(4):803
C57BL/6J mice
High-fat diet-induced nonalcoholic fatty liver model
Gavage
300 mg/kg
Once daily for 16 weeks
Theanine significantly reduced body weight gain, hepatic steatosis, and serum levels of ALT, AST, TG, and LDL-C in HFD-induced mice.
To evaluate the effect of theanine on controlling gray mold in strawberries. Results showed that 5 mmol L?1 theanine treatment significantly reduced the disease incidence and severity of gray mold and maintained higher fruit firmness.
Food Chem X. 2024 Aug 24;23:101772
Caenorhabditis elegans
Ultraviolet C (UVC)-exposed nematode model
Administered via K agar plates
50 µg/mL
Continuous for 48 hours
L-theanine treatment enhanced the removal of mtDNA damage and extended lifespan by activating autophagy, mitophagy, mitochondrial dynamics, and mitochondrial unfolded protein response (UPRmt) in UVC-exposed nematodes.
Molecules. 2024 Jun 6;29(11):2691
Sprague Dawley (SD) rats
Anterior cruciate ligament transection (ACLT)-induced osteoarthritis model
Oral gavage
50, 100, 200 mg/kg
Once daily for 6 weeks
L-theanine significantly alleviated ACLT-induced OA lesions, reduced OARSI scores, decreased serum levels of C2C and CTX-II, and lowered the expression of COX-2, PGE-2, iNOS, and NO.
Nutrients. 2020 Jul 3;12(7):1988
Mice
Stress-loaded mouse model
Oral
6 mg/kg
Two months
Theanine intake improved depression-like behavior in stress-loaded mice and modulated hippocampal metabolite levels.
Int J Mol Sci. 2020 Dec 28;22(1):193
Mice
SAMP10 and ddY mice
Oral
6 mg/kg
Continuous intake
Theanine intake suppressed stress-induced brain atrophy and altered the expression of Npas4 and Lcn2.
Nutrients. 2020 Jan 8;12(1):174
C57BL/6J male mice
High-fat diet-induced obese mouse model
Gavage
900 mg/kg
Once daily for 26 weeks
Theanine ameliorates obesity-related complications induced by high-fat diet in mice by suppressing lipid metabolism and inflammation pathways, including reducing body weight gain, fat deposition, glycolipid metabolism disorders, and hepatic steatosis.
Foods. 2024 Sep 19;13(18):2977
ICR mice and SD rats
Pentobarbital-induced sleep model and caffeine-induced wakefulness model
Oral
GABA/ L-theanine mixture (100/20 mg/kg)
Sleep latency and duration were measured 40 minutes after administration
The GABA/theanine mixture significantly reduced sleep latency and increased sleep duration, showing synergistic effects compared to GABA or theanine alone.
Pharm Biol. 2019 Dec;57(1):65-73
Balb/c mice
Caffeine-induced sleep disturbance model and pentobarbital-induced sleep model
To investigate the effects of Mg-L-theanine complexes on sleep quality and brain electrical activity. Results showed that Mg-L-theanine complexes, especially those with higher magnesium concentrations, significantly increased the expression of GABAergic, serotonergic, and glutamatergic receptors, decreased ECoG frequency, increased amplitude, enhanced delta wave power, and increased dopamine, serotonin, and melatonin levels while decreasing MDA and increasing antioxidant enzyme levels.
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