It seems as though high stress levels and sleep deprivation are becoming commonplace for many these days. Unfortunately, medicating for these conditions come with risks and side effects that can be anxiety-inducing themselves. But what if there was a natural supplement that could help combat this?
Enter L-theanine.
L-theanine is a natural compound present in a small percentage of foods and has been associated with a wide range of benefits including aiding in the treatment of sleep disorders and reducing stress and anxiety symptoms. If you are struggling with managing your sleep or stress levels and aren’t ready to consider traditional medications, a supplement may be the answer you are looking for.
What is L-Theanine?
L-theanine is an amino acid that can be found in a small population of certain foods, such as green, black, and white varieties of tea and some species of mushrooms, such as Bay Bolete. It does not fall into the category of essential amino acids however, our body is not able to produce L-theanine on its own [1].
If you aren’t a mushroom or tea lover, it may be challenging for you to get this beneficial compound in your diet. Because it has been associated with many health benefits, it can be found in many supplements including pills, capsules, gummies, and powders.
Additionally, research has found L-theanine to have many potential health benefits aside from sleep and stress management, causing this compound to explode in popularity over recent years.
5 Benefits of L-Theanine

Taking L-theanine supplements has been associated with a range of health benefits, including improved sleep, better mental focus, improved mood and reduced stress levels, better blood pressure management, and increased immunity.
Improves Sleep
According to research, taking an L-theanine supplement may help improve sleep, specifically in those who have difficulty with falling asleep. Unlike sleep medications, L-theanine does not act as a traditional sedative and taking it will not result in dependance. But rather l-theanine helps to naturally stimulate anxiolysis, a state of being relaxed but awake. Anxiolysis is required for high-quality sleep [2].
L-theanine may also help to improve sleep quality by helping you to relax. Sipping on a cup of tea or taking an l-theanine supplement can help to promote relaxation by reducing your resting heart rate without making you feel drowsy [3].
Although the act of sipping on a hot cup of tea can be relaxing in itself, taking a l-theanine supplement can be an easy way to get in a consistent amount of l-theanine daily.
For convenience, choosing a high-quality powder supplement you can easily mix into foods and beverages is an easy option, such as Naked Nutrition’s sleep aid supplement.
This product contains 200 mg of l-theanine along with other beneficial ingredients for sleep, such as melatonin and GABA (gamma amino butyric acid).
2. Boosts Mental Clarity
If sleep is not what you’re after right now, pairing L-theanine with caffeine may help boost mental clarity and focus. According to one small study, taking 97 mg of l-theanine combined with 40 mg of caffeine helped to increase mental focus for a group of young adults when given difficult tasks [4].
Another study a few years later found similar results when combining 100 mg of L-theanine with 50 mg of caffeine. Participants who were given difficult tasks had fewer errors than those in the placebo group. Although the research on l-theanine and improvements in focus is promising, more research is still needed to determine how this compound might help improve mental clarity in individuals [5].
3. Reduces Stress and Anxiety
Because L-theanine helps to induce a state of relaxation without subsequent drowsiness, it is believed to be a helpful compound for treating stress and anxiety symptoms.
A randomized, placebo-controlled trial conducted in 2019 on 30 participants taking 200 mg of l-theanine for 4 weeks found that taking an l-theanine supplement might help to improve mental health and reduce stress-related ailments in individuals with no psychiatric illness. Additionally, a review of 5 randomized-controlled trials found that 4 out of the 5 studies linked l-theanine supplementation to improvements in stress and anxiety symptoms [6,7].
4. Boosts Immunity
Some studies support l-theanine for improved immunity but its actual effects on our immune system are still unknown. Some researchers believe that because l-theanine helps with sleep and stress levels it naturally boosts our immune system while other studies have found that l-theanine may help with reducing inflammation and decreasing the risk of upper respiratory infections and the flu. Some of these results can likely be attributed to the catechins found in green tea that provide antioxidant effects [8, 9, 10].
5. Improves Blood Pressure
During stressful situations, it’s common for our heart rate and blood pressure to rise. Because l-theanine may help reduce stress, it may also help individuals reduce their heart rate and better manage their blood pressure.
How Much L-Theanine Should I Take?
There is no current recommendation for dosage of l-theanine at this time. Based on current studies, taking a supplement that contains 100-200 mg per serving will likely provide the most benefits however, this doesn’t translate to whole foods.
If you prefer to get your l-theanine from food sources, be mindful of your caffeine intake. If you are interested in taking an l-theanine supplement, be sure to consult your doctor or healthcare provider first.
Are There Any Side Effects?
L-theanine supplements are considered safe and no significant side effects have been recorded from taking them. However, it’s important to mention that dietary supplements are not regulated by the Food and Drug Administration (FDA).
Individuals undergoing cancer treatment should avoid taking l-theanine supplements as certain compounds in these supplements, such as EGCG, a compound in green tea, may reduce the effects of certain chemotherapy drugs [11].
Additionally, taking large amounts of green tea instead of supplements can cause stomach upset and nausea and should be limited due to the caffeine content.
Bottom Line
L-theanine supplements are associated with many health benefits including improved sleep, better mental focus, improved mood and reduced stress levels, better blood pressure management, and increased immunity. Although more research is still needed on l-theanine, it is considered safe for most healthy adults.
When choosing an l-theanine supplement, be sure to choose one from a trusted brand and be mindful of the other ingredients provided in the product. Although there is no established recommended dosage at this time, choosing a supplement that contains between 100-200 mg will likely provide the best results.