From the Guidelines
L-theanine supplementation is recommended for its potential benefits in reducing stress and anxiety, improving focus, and supporting cardiovascular health, with a typical dosage of 200mg daily. According to the study published in Mayo Clinic Proceedings in 2021 1, L-theanine is a derivative of glutamate that has a dose-dependent decrease in blood pressure. The benefits of L-theanine include:
- Promoting relaxation without causing drowsiness by increasing alpha brain wave activity
- Influencing neurotransmitters like GABA, serotonin, and dopamine to reduce stress and anxiety
- Improving focus and attention, especially when combined with caffeine
- Enhancing sleep quality
- Potentially supporting cardiovascular health by helping to lower blood pressure in some individuals It is generally considered safe with minimal side effects, but those on blood pressure medications should consult their healthcare provider before starting L-theanine supplements as it may enhance their effects. The study suggests holding L-theanine 24 hours before surgery 1, but for general health benefits, it can be taken as needed for acute stress or regularly for ongoing benefits.
From the Research
Benefits of L-Theanine
- L-Theanine may help reduce stress and anxiety, with studies suggesting that it can decrease perceived stress and improve sleep quality 2, 3, 4
- It may also have a positive effect on cognitive function, particularly attention and reaction time, when combined with caffeine or taken alone 5, 2
- L-Theanine has been shown to increase alpha waves in the brain, which are associated with relaxation and selective attention 5
- Some studies suggest that L-Theanine may have neuroprotective and anti-seizure effects, although more research is needed to confirm these findings 5
- L-Theanine has been found to be safe and well-tolerated in most studies, with few adverse effects reported 6, 2, 3
Potential Therapeutic Uses
- L-Theanine may be useful as an adjunctive treatment for generalized anxiety disorder (GAD), although more research is needed to confirm its efficacy 6
- It may also be beneficial for reducing stress and improving sleep quality in healthy adults 2, 4
- Some studies suggest that L-Theanine may have potential therapeutic applications in schizophrenia, although more research is needed to explore this further 3
Mechanisms of Action
- L-Theanine may exert its effects by inhibiting the binding of L-glutamic acid to glutamate receptors in the brain, leading to a reduction in cortical neuron excitation 4
- It may also affect the sympathetic nervous system, leading to a decrease in heart rate and salivary immunoglobulin A responses to stress 4