Theanine promotes relaxation by regulating brain wave activity. It has been shown in research that, after taking 100 mg of Theanine, test subjects had an average 25% increase in alpha wave amplitude (α waves are associated with wakeful relaxation) within 30 minutes, and the effect lasted for more than 90 minutes. For example, a 2021 clinical trial at the University of Tsukuba in Japan found that subjects who received 200 mg of Theanine daily averaged an 18.7 percent decrease in anxiety scale scores and a 12.3 percent increase in sleep efficiency. Such a mechanism relates to Theanine’s capacity to cross the blood-brain barrier and inhibit the overactivation of glutamate receptors, its affinity as much as 65% of the NMDA receptor, effectively blocking neuroexcitatory toxicity.
At the neurotransmitter level, Theanine alleviates stress by increasing the levels of GABA (gamma-aminobutyric acid). In a 2023 Nature Neuroscience paper, 50 mg/kg of Theanine increased the level of GABA in the prefrontal cortex of rats by 12% and decreased cortisol levels by 27%. This effect was compared to commercial anti-anxiety drugs such as benzodiazepines with fewer side effects at 3.2% (compared to 22%). For example, a multinational pharmaceutical company’s double-blind trial in 2022 showed that 50 mg Theanine-containing energy drinks improved the heart rate variability (HRV) of subjects by 15%, while the drug group improved only by 9% and was associated with the risk of drowsiness.
The efficacy of Theanine has been confirmed by market applications. The Theanine product market size worldwide will be $480 million in 2023 with a compound annual growth rate of 7.5%, says Grand View Research. A case in point is a premium tea brand “Stress-resistant Green Tea Formula” with 35 mg of Theanine that saw a 43% sales growth in the first half year and a “19% improvement in focus” based on users (from 5,000 consumer surveys). In addition, electroencephalogram (EEG) monitoring showed that product users had a 14% decrease in the θ/ beta wave ratio, indicating a significant decrease in cognitive fatigue.
Pharmacokinetically, Theanine is characterized by a half-life of 1.2 hours and a peak plasma concentration (Cmax) of 5.2 μg/mL at 45 minutes. Its metabolism is CYP1A2 liver enzyme-dependent, which synergistically combines with caffeine to enhance the duration of its effect by 30 percent. One functional food company, for example, optimized Theanine (100 mg) to caffeine (50 mg), and this resulted in a 21 percent improvement in cognitive test scores and a 13 percent greater reduction in anxiety versus a single group.
Security data also supports its use. EFSA (European Food Safety Authority) analysis suggested no side effects at a tolerable daily dose of 400 mg of Theanine and LD50 of 5000 mg/kg (rat). Neurotoxicity risk was less for Theanine at 0.03% compared to standard sedatives such as benzodiazepines at 1.8%. The FDA approved an ADHD dietary supplement containing Theanine in 2020 for the adjunctive treatment of children with ADHD, and in clinical trials, the attention span of the children increased from 8.2 minutes to 14.5 minutes and decreased the number of abnormal behaviors by 31%.
Cumulatively, Theanine is a leading component in the stress management market through multi-target neuroregulation, safety, and quantifiable effects. The close combination of its business cases and scientific study data provides a recyclable solution for functional food and medicine research and development.