L-theanine and Dizziness: What Users Say

• Dan...
• Taken for 1 to 6 months
• March 26, 2020

For Dietary Supplementation "I have been taking this for about a month, and only now have I started having really weird side effects. At first, it seemed to be greatly helping my anxiety, and for about a week now, I have had awful heart palpitations. I originally thought it was stress but started realizing they would start back up after I took the l-theanine. I was taking 200 mg - 400 mg a day. I also experienced low-grade nausea, especially if I did not eat, as well as dizziness and fatigue. I'm pretty sure I cannot continue this. Also, when I went to the doctor, my blood pressure was very low, and it may have been due to this. I am a 31-year-old female in very good health."

• 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!"

• Sha...
• February 21, 2017

For Dietary Supplementation "I started taking this about two weeks ago for insomnia. It was combined with lavender oil as a natural sleep aid. It works for helping me to shut my brain off at night and fall asleep, but it caused severe dizzy spells and bad headaches. I also had some stomach upset. I hear that's a rare reaction, but just wanted users to be aware of the possibility. Today I had a dizzy spell so bad in the kitchen that I fell and hurt my hip. I am a 37-year-old woman."

• Ang...
• Taken for less than 1 month
• October 24, 2020

For Dietary Supplementation "I tried just one pill last night and shortly after felt really relaxed, like that feeling when you’re about to fall asleep. Then my heart was beating closer to 125 bpm for at least an hour or more. I felt dizzy and also nauseous. I won’t be taking this again."

• Wen...
• Taken for less than 1 month
• February 1, 2020

For Dietary Supplementation "Initially, I really benefited from the calm feelings when I took 200 mg at bedtime. Fell asleep more easily and had relief from falling asleep anxiety. After a few weeks, however, I started getting debilitating headaches, fogginess, dizziness, and fatigue. It confined me to home. I am very disappointed."

• Lil...
• Taken for 1 to 6 months
• December 30, 2020

For Dietary Supplementation "I've been using 200 mg of l-theanine combined with caffeine on and off for about 4 months now. At first, it was okay, but I would have this weird dizziness that would fade away after some time. I loved the way it kind of made me 'wake up' for hours so I could work and study with full focus. However, this month and last month have been horrible for me with regards to taking these pills. I've started to feel tingly and numb in the hands and feet, and I have this awful dizziness accompanied by horrible heartburn. I feel like I am living in another dimension right now as everything around me is spinning. I took the pills last night for me to finally realize that this isn't for me. I did not sleep all night long! I still feel restless 10 hours later, and the numbness, dizziness, and heartburn are still there. I am a perfectly healthy woman, and trust me, this supplement isn't for everyone, so be careful."

• 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."

• Gen...
• Taken for less than 1 month
• July 11, 2019

For Dietary Supplementation "48-year-old male. Took it for general anxiety disorder, tried every med out there, almost everyone, some worked for a couple of years then stopped working so I go to another, on these meds for 19 years, very medication sensitive, got off all meds a year ago, still had a little anxiety so took l-theanine for about a week, worked really well for 7 days then suddenly developed a massive headache with extreme neck pain and dizziness. I stopped taking l-theanine 250 mgs. It's been 2 days since I stopped and the headache and neck pain are almost gone. Definitely not for me, allergic to pain lol!"

• Hal...
• Taken for less than 1 month
• September 14, 2019

For Dietary Supplementation "I was very stressed in the last weeks, so I thought that it’s time to try this out. (I am eating healthy, working out every 2nd day.) I took 100 mg last night and slept very well. The next dose today morning then... mmm... I felt so strange... I couldn’t think clearly, I felt dizzy. I was at the store and suddenly I felt that I would lose my balance... I felt that my heart would explode. Personally, I don’t recommend it."

• Bet...
• April 22, 2020

For Dietary Supplementation "I took this supplement this morning on the way to work. By the time I got to work, I felt a little tired and dizzy. Within an hour, I became so nauseous and dizzy, and my head felt tight, and my neck got stiff, and my arms started to feel weak, and I got a little confused when trying to talk. I had to leave and go home. I still feel all of those things. I will not be taking this supplement again."

• K F...
• June 21, 2017

For Dietary Supplementation "I already drank green tea and did not realize this was in my other multivitamin supplement. This made me so dizzy after a few days I could not drive or barely think straight. It also caused extreme fatigue for me. I am only 46 and in good health/fit. I would have crashed a car if I had driven in the last 24 hours. Please be careful with this."

• 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."

• jiv...
• Taken for 2 to 5 years
• April 27, 2021

For Dietary Supplementation "I've been using this for years. The first to counter glutamate sensitivity or reactions, which it does very well. I've used it to relax, but (for me) it lasted too long. I felt my most relaxed and tired about 8 hours after I took it, so I assume it has a long half-life. It's not something to chill you for 2 or 3 hours. For the last 9 months or so, I've been using it to help sleep. Just 100 mg a few hours before bed helps, but doesn't keep me asleep for more than 4 hours. I find adding anything to this, like melatonin or inositol, to improve sleep just causes side effects. In fact, just the L-theanine alone after 8 months or so of use started to cause all-day dizziness and headaches that made me have to stop using it. I keep it now in case I eat something dining out that's very high in glutamate (like seafood) or has unlabeled MSG, as I do get reactions like elevated BP and pulse, which this definitely helps with. Great for occasional use."

• ren...
• Taken for less than 1 month
• February 22, 2022

For Dietary Supplementation "I took 200 mg and started to feel dizzy, heart and hands burning sensations, like a feeling of fear. I just want to relax. Never ever take it anymore."

• Anonymous
• January 29, 2022

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

• Maa...
• Taken for less than 1 month
• November 7, 2020

For Dietary Supplementation "After two days of taking 200 mg once a day, I felt dizziness, and my body relaxed overall."