L-Theanine 250mg
L-Theanine 250mg
150 Capsules
Helps Promote Relaxation
Preferred Nutrition L-Theanine is a one-per-day formula that helps to temporarily promote relaxation without causing drowsiness. L-theanine is an amino acid that occurs naturally in green tea. It is absorbed quickly and is non-habit-forming, making it a suitable supplement for occasional or daily use. Each vegetarian capsule contains 250 mg of L-theanine.
- Helps to temporarily promote relaxation
- Contains 250 mg of L-theanine per vegetarian capsule
- Features a convenient one-per-day dose
- Non-GMO and suitable for vegetarians/vegans
| Each vegetarian capsule contains: | |
| Medicinal ingredient: | |
| L-theanine | 250 mg |
Non-medicinal: Vegetarian capsule (carbohydrate gum [cellulose], water), rice flour, vegetable grade magnesium stearate (lubricant), silica.
This product does not contain artificial preservatives, colours, or sweeteners; no dairy, sugar, wheat, gluten, yeast, soy, corn, egg, fish, shellfish, animal products, salt, tree nuts, or genetically modified genes or proteins. Suitable for vegetarians/vegans.
Although stress is a natural response to the pressures of daily life, relaxation is essential for restoring balance in both the mind and body. Long-term daily stress is detrimental to both mental and physical health, impacting sleep and exhausting the body’s stress-coping mechanisms. Prioritizing relaxation is a key component of sustained health and overall quality of life (Sakamoto et al., 2019; Rogerson et al., 2024; Wang et al., 2022).
Drinking tea has long been associated with feelings of relaxation, an effect that is attributed to its L-theanine content (Wang et al., 2022). L-theanine is an amino acid found primarily in green tea leaves (Bulman et al., 2025).
Research studies suggest that L-theanine is absorbed easily into the bloodstream, where it can rapidly cross the blood-brain barrier. By modulating key neurotransmitters, L-theanine stimulates the production of alpha brainwaves, a physiological process associated with a relaxed yet alert state of mind (Bulman et al., 2025; Nobre et al., 2008). In a placebo-controlled study, participants who took a low 50 mg dose of L-theanine while resting with their eyes closed experienced a significant increase in their alpha brainwave activity relative to the placebo group. EEG measurements suggested that alpha brainwave activity increased linearly over a period of 45–105 minutes post-supplementation (Nobre et al., 2008).
Clinical studies supplementing L-theanine at doses of 200–400 mg per day suggest that it improves subjective feelings of relaxation. It also reduces measures of physiological stress response, such as cortisol levels and heart rate (Bulman et al., 2025; Wang et al., 2022; Sakamoto et al., 2019).
L-theanine is believed to work quickly, with studies showing measurable effects within approximately 30 minutes of supplementation (Nobre et al., 2008). Because of L-theanine’s fast action, even a single dose can offer positive benefits (Furushima et al., 2022). In a randomized, placebocontrolled trial, an acute 200 mg dose of L-theanine was found to significantly improve measures of relaxation in healthy university students exposed to a psychological stress test. Students who supplemented with L-theanine had reduced salivary alpha amylase (sAA) levels 15 minutes after exposure to a stress-loading test (Furushima et al., 2022).
Stress and nervousness can negatively impact mental clarity and response to surroundings. In a double-blind, placebo-controlled crossover study, healthy sleep-deprived adults who supplemented with 200 mg of L-theanine before completing a simulated traffic-scene-based attention task displayed greater selective visual attention and processing speed than participants who took a placebo. Taking L-theanine was associated with significantly fewer false alarms, improved ability to discriminate targets from distractions, and a faster reaction time during the test (Karunaratne & Dassanayake, 2025).
Although L-theanine does not cause drowsiness or promote sleep directly, taking it close to bedtime is well-recognized for improving sleep disturbances caused by psychological stress (Sakamoto et al., 2019). A systematic review and meta-analysis of 18 randomized controlled trials found that participants who supplemented with L-theanine in a range of formats and doses significantly improved their subjective ratings of how long it took to fall asleep, their ability to function during the day, and their overall sleep quality (Bulman et al., 2025).
Preferred Nutrition
