L-theanine and Anxiety: What Users Say

• lis...
• Taken for less than 1 month
• March 7, 2021

For Dietary Supplementation "I got horrible chest pain and tachycardia (fast heart beats) and palpitations from just 50 mg every time I took it. I haven’t found any warnings of these side effects for this until I came on here. This site is so helpful. Be very careful with this supplement. Start very low and look out for worsening mood and anxiety. I can’t believe no other websites list these common side effects."

• Chl...
• November 15, 2019

For Dietary Supplementation "I started taking L-Theanine about 3 months ago and I think at first I felt it helped my sleep. The last month has been horrendous. I literally would wake up 6-8 times a night wide awake. Sometimes even felt extremely anxious like a panic attack was coming on. I was wide awake all night long then exhausted the day after. Averaging 3-4 hours of restless sleep every night. I was getting extremely worried about what was happening to me. I was running low on my pills and about to order another bottle but decided to research L-theanine a little more first and saw other people having similar side effects so I immediately stopped taking them which was 3 days ago. The last 2 nights I slept so much better. No more waking up 8 times a night in a panic. I also have the MTHFR gene mutation which may be the reason why it has the opposite effect on me. L-theanine increases GABA levels which has opposite effect on those of us with the MTHFR gene mutation. My bottle is going in the trash!"

• Aid...
• Taken for less than 1 month
• November 6, 2019

For Dietary Supplementation "I began taking L-theanine before bed for about a week—just enough time for it to really exhibit effects—I forgot about it for 1-2 days and started again. When I started again, I experienced a large spike in anxiety compared to usual. I felt spacey, anxious, frustrated, and even violent. I am not diagnosed with any anxiety disorders but definitely experience occasional anxiety, especially in social settings and when trying to sleep. After reading a plethora of reviews, the bottom line is this: this medication is sketchy. It’s not well-studied, and the physiological mechanisms are not well outlined in literature. I’m a biochemistry major at a strong institution, so I’m not out of my element with this statement. Consult a psychiatrist before starting a dosage regimen. Hope this helps."

• lif...
• Taken for less than 1 month
• September 24, 2020

For Dietary Supplementation "I write this as I was searching for adverse effects from l-theanine. Well, lo and behold, I see others on there have also experienced dizziness and strange symptoms. I currently take 1 mg of Klonopin and 50 mg of Zoloft daily. I decided to try 200 mg of l-theanine last night. My hands are still shaky as I type this almost 24 hours later. I was unable to leave my house today due to dizziness, exhaustion, depression, and anxiety. When I woke up last night to go to the bathroom, I felt like the room was spinning, and I awoke from a coma. I can only conclude that the l-theanine reduced my blood pressure to near zero. There were no indications that I could not take it with the medications I am on. Well, guess what? IT HAD A VERY BAD ONE! Those of you on medications, be very cautious!"

• Anonymous
• Taken for less than 1 month
• March 8, 2021

For Dietary Supplementation "I took l-theanine combined with melatonin to help me fall asleep, and my experience was awful. It made me almost jittery, and although I was very tired, I couldn’t go to sleep because of the restlessness it caused. Once I did fall asleep, I woke up frequently feeling really anxious."

• Anonymous
• Taken for less than 1 month
• March 8, 2021

For Dietary Supplementation "I took l-theanine combined with melatonin to help me fall asleep, and my experience was awful. It made me almost jittery, and although I was very tired, I couldn’t go to sleep because of the restlessness it caused. Once I did fall asleep, I woke up frequently feeling really anxious."

• Cor...
• Taken for 1 to 6 months
• May 11, 2020

For Dietary Supplementation "I have Cushing's disease and experience most days some anxiety, some days extreme anxiety, and rarely no anxiety. I call the no anxiety days the 'old me.' While I have been using a combination of homeopathic, allopathic, and herbal to control my anxiety, finding l-theanine felt heaven-sent. I wasn't just anxiety-free, I felt calm, in control, and even when I had an adrenal/Cushing cycle, the cycle was easily handled and recovery was quick. I was me again. Then my blood pressure started to experience unusual rapid drops, from 140/80 to 78/52. I am not sure if it is the l-theanine. I was taking 225 mg a day. So I have decided not to take it for a week. See what happens."

• GBa...
• Taken for less than 1 month
• January 11, 2021

For Dietary Supplementation "Tried to take for general anxiety and for calmness. Just 100 mg, 3 days in a row, caused the opposite: insomnia, anxiety, and also a strange capability to bring up bad memories. Moved me more towards a depressive state of mind."

• Myl...
• February 18, 2019

For Dietary Supplementation "Honestly, this really isn’t as great as it seems. Yeah, it will do its job and relax you, but to the point you start forgetting stuff. Being in weird moods. Your appetite will be different. Also, my stomach has just been feeling full, and heartburn happens easier than it did before. If I drink a beer or two, it just feels like I’m so full and get a weird feeling. Also, makes you have even worse anxiety after you take it. As if it makes you feel okay, but when it wears off or you don’t take it, you feel crazy. At least I did. I will no longer take this. I don’t recommend it unless you want to feel not like yourself. Don’t let it make you feel this is a thing that doesn’t have side effects because it does."

• Car...
• Taken for less than 1 month
• April 29, 2020

For Dietary Supplementation "I started theanine last week. It seemed great the first few days. Then, these past 2 days, it has triggered some really nasty anxiety attacks. I was up until 3 a.m. afraid to go to sleep for 2 nights in a row. It causes extreme thirst and hard and heavy heartbeats. I believe this drops my blood pressure too low in conjunction with propranolol. Will not take again. Be careful with this stuff."

• Anonymous
• Taken for less than 1 month
• July 17, 2020

For Dietary Supplementation "I only took two pills (200 mg each pill) over two days. The first day I seemed more focused, noticed I was reading through articles faster and seemed more alert, but not 'wired.' The second day, I felt really dizzy and brain foggy, anxiety spiked to where I felt like I couldn't even go outside, let alone go somewhere specifically, rapid heartbeat, and frequent trips to the bathroom. Threw the bottle in the trash and hopefully things will level back out in the next couple of days."

• pea...
• Taken for less than 1 month
• November 12, 2020

For Dietary Supplementation "I have had panic attacks for a few years now. I am on Effexor (75 mg) and Klonopin (very little). Since my doctor wants me off the Klonopin and my anxiety has seemed to get worse, I decided to find other alternatives. I looked to magnesium, which really seems to help. I noticed L-theanine, and like most of you, I took it and felt the anxiety. I was like, what? Isn't it supposed to relax me? Well, I felt just the opposite. It subsided on its own, and I wasn't sure it was the pill, so I took it again at bedtime, and yep, the same. So I won't be taking any more."

• Jda...
• Taken for less than 1 month
• October 4, 2019

For Dietary Supplementation "I've been having panic attacks. I researched and saw this was highly recommended. I took 100 mg in the morning. That's it. I only took one. It made me feel calm, then way too hyped up, and my heart started beating very fast. I got all jittery. I panicked because of the fast heartbeats! I thought I was having a heart attack. Never again."

• kat...
• Taken for less than 1 month
• July 30, 2019

For Dietary Supplementation "I struggle with Generalized Anxiety Disorder, and I hate the way medicines make me feel! I saw some stuff about l-theanine and was excited to try something holistic with so many great reviews. At first, it was great; I noticed a calming effect within 30 minutes, I felt focused and alert, and overall in a good mood. I started taking 2 100 mg pills a day. After 2-3 weeks, I started noticing some changes. I felt like I just couldn’t focus at all, was in a weird depressed mood, wanted to sleep all the time, had no motivation to go workout. And if I didn’t take it at all, I felt HORRIBLE: dizzy, anxious, bad headaches. I stopped taking it about 3 days ago, and I’m trying to adjust. It just didn’t agree with me; maybe I should have just been taking it a few times a week rather than every day, but I think for now I’ll just steer clear."

• Joh...
• January 29, 2022

For Dietary Supplementation "Let’s be clear here: supplements like this have clearly helped some folks. I just happened to fall on the other side of things, and it needs to be shared. As with others, I had a good first few days, and then days 4 and 5 were something entirely different, with heightened anxiety and depression deeper than I have felt before (worsened existing depression). I only took 200 mg in the morning and 200 mg at night. The moral of the story is to start low and start slow and write down what is happening. Talk to someone before taking this, because it can sincerely mess you up. I am a slow metabolizer, and that may play a role in my experience, just not sure."

• Oli...
• Taken for 1 to 6 months
• May 24, 2022

For Dietary Supplementation "I appreciate this does work for some people, and I agree it does relax you... until it wears off! For me, it gave me heart flutters and the worst anxiety ever once it wore off. I just didn't feel like myself and felt like I had a very low mood. Would not recommend, but I appreciate everybody's body chemistry is different. I'll stick to meditation and herbal teas."

• Syl...
• Taken for less than 1 month
• December 26, 2024

For Dietary Supplementation "I started taking L-Theanine for sleep. It worked well, associated with magnesium glycinate and chelate. I could sleep very well, but I started to be depressed and very anxious as soon as I woke up and during the day. I am normally a very happy and active person. So I had to stop taking it, and I went back to my happy mood."

• RJA...
• Taken for less than 1 month
• October 26, 2021

For Dietary Supplementation "I discovered L-theanine by accident through drinking green tea, which I noticed had a hugely positive effect on my mental state - feeling relaxed, calm, as well as alert with mental clarity. This led me to buy L-theanine supplements, and unfortunately, dosages from 40 mg to 400 mg each caused me physical and mental discomfort - headache, nausea, anxiety, and lack of focus. I wondered if I am sensitive to the L-theanine and should try out micro dosages."

• Lon...
• Taken for less than 1 month
• September 6, 2021

For Dietary Supplementation "I took one 200 mg pill of l-theanine to help me get rid of anxiety about one hour before I wanted to go to sleep. It elevated my anxiety with horrifying nightmares. In these nightmares, people looked like hideous mutants. I woke up several times, or I think that I did, and the horror was still playing. The nightmare came to life. That was an experience that I never want to relive! Ashwagandha works far better for me."

• She...
• Taken for less than 1 month
• January 12, 2022

For Dietary Supplementation "I took 200 mg about a month ago for a few days to help with anxiety. It seemed to work at first, but then I felt more anxious as it wore off later. I also had a burning feeling in my stomach and reflux. The second day I took it with caffeine/coffee. I was very focused-like a robot, getting things done. The burning continued, even after taking my reflux meds. I again felt anxious when it wore off. Recently, I just took some melatonin and didn’t realize it had 200 mg of l-theanine. I later had cramping and diarrhea. That is not normal at all for me. I also woke up in the night feeling very anxious. I think it’s all from the l-theanine. I would not have taken it recently if I’d known it was in the melatonin. Magnesium works much better for me for calm and sleep, but you have to use the glycinate kind or it can cause gastro issues. I think it could help some people, but the side effects were terrible for me. In fact, it caused anxiety instead of helping it."

• Rut...
• Taken for less than 1 month
• April 15, 2020

For Dietary Supplementation "This drug increased heart rate, felt sedative, and at the same time, more depressed and stressed."

• Eme...
• Taken for less than 1 month
• November 6, 2021

For Dietary Supplementation "Opened a capsule and took some, and immediately felt anxious, nauseated, and worried with palpitations. Will not try again."

• Eme...
• Taken for less than 1 month
• November 6, 2021

For Dietary Supplementation "Opened a capsule and took some, and immediately felt anxious, nauseated, and worried with palpitations. Will not try again."

• Anonymous
• January 29, 2022

For Dietary Supplementation "I experienced dizziness, faster heartbeats, and heightened anxiety when trying to sleep."