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.
Previous studies suggest that L-theanine exerts its relaxant effect by enhancing GABA levels, thereby increasing the expression of dopamine and serotonin in the brain (11–13).
Better sleep, feeling calmer, and helping to raise serotonin and dopamine are all ways l-theanine contributes to a mood boost.
The GABAA receptor blocker bicuculline produced an approximately three-fold increase in DRN serotonin. In conclusion, glutamate neurotransmitters have a weak tonic excitatory influence on serotonergic neurons in the rat DRN. However, the predominate influence is mediated by GABA(A) receptors.
Conclusions. This study demonstrates that chronic L-theanine supplementation (8 weeks) is quite safe and features with diverse beneficial effects on the improvement of depressive symptoms, sleep disturbance, anxiety, and cognitive impairment functions in patients with MDD.
Possible Drawbacks of L-Theanine for Anxiety
Can Decrease Serotonin Levels While L-theanine also has the potential to increase serotonin levels in the brain, it has occasionally been shown to decrease them as well.
Here's how it works: L-theanine increases the brain's production of serotonin and dopamine production, and GABA. [4] Serotonin and dopamine (known as “the happy hormones”) and GABA are all neurotransmitters and play a role in regulating mood, emotion, alertness, concentration, sleep, and other bodily functions.
Certain drugs and substances such as caffeine, alcohol, nicotine, NutraSweet, antidepressants, and some cholesterol-lowering medications deplete serotonin and other neurotransmitter levels. Hormone changes cause low levels of serotonin and neurotransmitter imbalances.
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.
Some inherited genetic disorders may affect the body's ability to make or metabolize serotonin. Lifestyle and other factors that may also play a role include: Hormonal shifts, such as due to beginning or stopping hormone replacement therapy, menopause, pregnancy, or advancing age. Lack of sunlight.
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.
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.
Moderate daily intake of L-Theanine is safe, and no side effects were reported in any published study. High doses on daily basis will lead to: Lowering blood pressure (which may be beneficial to some people).
Magnesium works as an important co-factor required for conversion of tryptophan (from proteins we get from food) to serotonin and melatonin, both of which help in falling asleep."
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.
About 20 minutes after ingestion, L-theanine naturally lowers the body's cortisol levels. Cortisol is that pesky hormone that shoots up when you're feeling stressed (a not-so-fun fact, it also aids the body in storing fat, too).
Mix with cold or hot water for a soothing drink before bed. Amounts of L-theanine of 900 mg daily have been used safely, although most adults consume smaller doses of 200-400 mg daily. Thorne's Theanine provides 200 mg per capsule.
5-HTP has an average rating of 6.5 out of 10 from a total of 151 ratings on Drugs.com. 54% of reviewers reported a positive effect, while 25% reported a negative effect. L-theanine has an average rating of 5.2 out of 10 from a total of 137 ratings on Drugs.com.
Regular exercise for at least 30 minutes each day improves one's overall mood. Research has revealed that long-term cardiovascular exercise boosts serotonin levels in the brain. Serotonin can lower hostility and symptoms of depression. It also encourages agreeableness.
B12 acts as a cofactor in synthesis of neurotransmitters such as serotonin and dopamine, thus B12 deficiency affects mood, emotions and sleeping and can lead to psychiatric disorders.
Dopamine: Often called the "happy hormone," dopamine results in feelings of well-being. A primary driver of the brain's reward system, it spikes when we experience something pleasurable. Praised on the job? You'll get a dopamine hit.
Folic acid and vitamin B12 are involved in the synthesis of serotonin and other neurotransmitters. Vitamin B12 deficiency has been found in many patients who have depression or decreased attention, concentration, and memory.