The most common side effects of L-theanine dosage include headaches, nausea, and irritability. However, the nausea appears to be mostly linked with L-theanine being administered through green tea rather than dietary supplements.
When taken by mouth: L-theanine is possibly safe when used short-term. Doses of up to 900 mg daily have been safely used for 8 weeks. It isn't clear if L-theanine is safe to use for longer periods of time. It might cause mild side effects, such as headache or sleepiness.
After taking advice from experts, the FDA classified L-theanine as “generally recognized as safe.” This classification means that they believe this additive to be safe when people use it as the packaging suggests. However, women who are pregnant or breastfeeding should not use L-theanine.
The amino acid L-theanine is an effective treatment of moderate and severe anxiety and does not cause drowsiness.
After being absorbed into the body, L-theanine can penetrate the blood-brain barrier and regulate the secretion of neurotransmitters of central nervous system cells [13] and levels of hormones such as corticosterone (CORT) and adrenaline (EPI) in the serum.
Most people can safely take up to 200 milligrams daily (usually split into two to three doses), although higher doses around 400 milligrams have also been used safely. L-theanine can interact with certain medications, including those taken to control high blood pressure (called antihypertensive drugs) and stimulants.
In fact, explains Kramer, just one 200 to 400mg capsule can ease stress, lower your cortisol levels, and get you to a state of zen in 20 minutes. And, if you want, you can safely consume L-theanine every day.
l-theanine (γ-glutamylethylamide), an amino acid in green tea, has been shown to affect brain functions by relieving stress disorders, improving mood, and maintaining normal sleep.
L-theanine can help foster a state of calm, attentive wakefulness. L-theanine has positive effects on both the mental and physical symptoms of stress, including lowering heart rate and blood pressure. Research suggests that L-theanine can help reduce anxiety in people with schizophrenia and schizoaffective disorder.
Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects.
You can take L-Theanine multiple times daily, including in the morning before work and at night before bed. Taking a daytime dose of L-Theanine may help you focus and maintain mental clarity as you go about your daily tasks. A nighttime dose, on the other hand, can help you wind down before getting ready for bed.
To the best of our knowledge, tea is the only main dietary source of L-theanine.
L-theanine has been historically reported as a relaxing agent, prompting scientific research on its pharmacology. Animal neurochemistry studies suggest that L-theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors.
2. Stays in system approx. 8 hours with maximum concentration within 1 hour. Increased heart rate, constricts blood to brain, diuretic, tremors, headache, anxiety.
Many holistic health care professionals suggest starting with a daily dose of 100 milligrams of l-theanine, increasing to a maximum of 400mg per day, for the treatment of stress or anxiety. Effects are usually noticeable within 30 minutes, and can last as long as eight to ten hours.
L-theanine may offer a natural way to treat ADHD. L-theanine can help improve attention and focus and has a calming effect on the mind. It is also relatively safe, with few side effects. If you are considering taking L-theanine for ADHD, it is important to talk to your doctor first.
When it comes to L-theanine and GABA, L-theanine wins the battle to cross the blood brain barrier. Once consumed, it can easily cross the blood brain barrier and its effects on the brain are noted within 30 minutes [7]. L-theanine helps to promote relaxation without making you drowsy.
Theanine occurs naturally in green tea, but the concentration is very low. A typical cup of tea also contains around 45-60 milligrams of caffeine[27]. In contrast, high-quality coffee naturally contains an average of approximately 180 milligrams of caffeine per serving, but no l-theanine[28].
The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci.
With that in mind, L-theanine seems to be particularly beneficial for combatting stress-related sleep issues. Melatonin, on the other hand, just flat out encourages sleep. This is what makes melatonin a generally more effective sleep supporter than L-theanine, or any other natural sleep aid.
Magnesium is one of the most effective (and natural) supplements you can take for sleep. You can read our full guide to magnesium and sleep here, but it promotes deep sleep and full body recovery. When you combine l-theanine and magnesium - you get the best of both worlds.
To optimize uptake from the intestine and across the blood brain barrier, L-theanine may be best taken on an empty stomach, and especially away from protein foods and amino acid-containing supplements.
L-theanine inhibits the expression inflammatory factors in the liver tissue. (A) Immunoblot showing expression levels of iNOS, IL-1β and IL-6 in the indicated groups.
Theanine /ˈθiːəniːn/, also known as L-γ-glutamylethylamide and N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species.