The March 2022 American Psychological Association survey of stress levels among Americans highlighted a significant increase in stress, noting it’s the highest since the survey began in 2007. Stress and anxiety are closely linked and can severely impact health, contributing to conditions like hypertension, heart disease, IBS, eating disorders, substance abuse, and neurodegenerative diseases. With these challenges, many are seeking natural ways to reduce stress and enhance their quality of life.
L-theanine, an amino acid from the tea plant (Camellia sinensis), offers a promising natural solution. The medicinal benefits of tea have been recognized since 2737 BCE. Chinese scholars have long praised tea for its ability to bring peace, relaxation, and even longevity.
Modern Science Confirms the Value of Tea
Scientific studies support these ancient beliefs. A 2007 placebo-controlled study found that six weeks of tea consumption helped participants recover more quickly from stress, reducing cortisol levels and promoting relaxation. While the rituals of tea drinking contribute to calmness, the bioactive ingredients in tea leaves, particularly L-theanine, play a significant role. This amino acid, found in black, green, and oolong teas, is known for its calming effects.
L-theanine’s chemical structure is similar to glutamate, a key neurotransmitter in stress responses. It helps decrease cortisol levels by inhibiting the stress response. Additionally, L-theanine increases gamma aminobutyric acid (GABA)-A, the main inhibitory neurotransmitter in the brain, fostering a sense of calm.
Theanine Counteracts the Effects of Stress
Stress triggers the nervous system to release vasoconstricting hormones, raising blood pressure. Fortunately, L-theanine can lower heart rate and blood pressure during stress and mental challenges, especially in those prone to anxiety. In one study, participants performing a challenging task experienced reduced blood pressure and anxiety with L-theanine.
Similar anti-anxiety effects have been observed in various studies. In another study, a 200 mg dose of L-theanine reduced heart rate, stress scores, and salivary immunoglobulin A levels, an objective stress marker. Pharmacy students also reported lower stress levels and reduced sympathetic nervous system activity with L-theanine supplementation.
Human EEG studies show that L-theanine induces alpha brain waves within 40 minutes of intake, indicating relaxation and improved creativity, performance under stress, and concentration. A 200 mg dose of L-theanine is equivalent to about eight cups of black tea, highlighting its potency compared to tea consumption.
Theanine Sharpens the Mind
Tea contains caffeine and L-theanine in a 2:1 to 4:1 ratio, depending on the type and preparation method. While caffeine can enhance alertness, it counteracts L-theanine’s relaxing effects. Remarkably, a single 200 mg dose of L-theanine can enhance concentration without raising blood pressure.
Clinical trials confirm that L-theanine improves attention, allowing individuals to focus on their goals without distraction. Electrophysiological recordings show L-theanine’s specific effect on brain attention circuitry, sustaining focus during difficult tasks. In a study of healthy adults, consistent L-theanine use improved verbal fluency, decision-making, and mood, partly due to increased dopamine levels.
Theanine Supports and Protects the Brain
Research suggests that tea or L-theanine consumption may protect the brain from chronic stress, aging, and cognitive decline. L-theanine promotes brain neuron regeneration and boosts brain-derived neurotrophic factor (BDNF), enhancing learning and memory. It may reduce the risk of Alzheimer’s and other neurodegenerative diseases.
A study showed that green tea extract and L-theanine improved memory in adults with mild cognitive impairments. L-theanine also slows Parkinson’s disease progression in animal models, offering antioxidant and anti-inflammatory benefits.
L-theanine is a popular supplement for relaxation, mood improvement, stress reduction, and brain health support. It is important to source vitamin and herbal extracts from a trusted source as there are significant amounts of counterfeit supplements in the market today, especially since the supplement market is not regulated by the FDA. Your certified functional medicine practitioner can recommend a supplement containing this ingredient if indicated for your treatment plan, and can help you source a trusted product form a 3rd party verified lab. If stress affects your quality of life, consider giving L-theanine a try with the help of your functional doctor.
Our licensed naturopathic doctor and experienced functional medicine practitioner offers comprehensive functional medicine consultations in Meridian / Boise, Idaho. Free discovery calls are available!
