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L-theanine and Tremors: What Users Say

Tremors: mentioned by 6 users (4.2%)

Based on user experiences from 143 L-theanine reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

anxiety 16.8%
dizziness 11.2%
heart palpitations 11.2%
headaches 9.8%
increased heart rate 5.6%
depression 4.9%
nausea 4.9%
tremors 4.2%
brain fog 3.5%
tiredness 3.5%

Reviews for L-theanine

Commonly mentioned side effects
  • 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!"

1 / 10
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73 Report
  • gol...
  • Taken for less than 1 month
  • November 28, 2021

For Dietary Supplementation "I am a 21-year-old female with medicated ADHD, but no other health problems. Everything I've read has said that L-theanine helps with ADHD stimulant medication jitters, without any side effects. I took 200 mg yesterday afternoon. What followed was what I felt was the worst human experience imaginable. Within 40 minutes, and for 5 hours afterward, I was dissociating for the first time in my life (everything felt distant and like I wasn't in my own body), every muscle was twitching, I was easily startled, tachycardia, I could not stop crying, and every time I closed my eyes, all I could see were rapid flashes of light, as if I was seeing my own neurons firing off. This supplement took me to depths of sadness that I did not know were possible for anyone to feel. Even now, well over 24 hours later, whatever trace amount of L-theanine is still in my system has rendered my ADHD medication useless, and I am still unwell. I hope it clears within the next few days-I just want my life back."

1 / 10
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28 Report
  • NYg...
  • Taken for less than 1 month
  • August 26, 2018

For Dietary Supplementation "The first time I took 100 mg of L-Theanine, it made me feel spacey, tired, and gave me a headache. It did calm me down, I felt my dopamine level rise, but the overall feeling was somewhat uncomfortable. A lot of sources recommend having coffee with it. I loved the combination. It made me feel happy, motivated, and energetic, but that didn’t last long. In 5 hours, I started to have a bad crash. I had jitters all over my body, and my heart rate was very high. I took 50 mg of L-Theanine to calm down, but it didn’t feel the same the second time, not the same mood, and I felt cranky, but it relaxed me. Since I don’t feel right after a calm down, I take 5-HTP after. I also pair L-Theanine with 5-HTP for sleep and have happy dreams, sleep, and wake up with a smile. I recommend that combination for people who suffer from depression. For those who suffer from anxiety, don’t have it with coffee and be careful with it, calm downs can be pleasant. Could be the brand too, get a quality brand."

7 / 10
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25 Report
  • cma...
  • Taken for less than 1 month
  • December 20, 2021

For Dietary Supplementation "If you have low blood pressure, do not take L-theanine. I took only a single capsule and have felt lightheaded and shaky to the point that my body is trembling. I feel like I am going to pass out. I was prescribed L-theanine for my general anxiety. You would think that considering I have a history of low blood pressure, the doctor would mention it could lower my blood pressure further. I guess it is on me for not doing enough research."

2 / 10
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3 Report
  • cma...
  • Taken for less than 1 month
  • December 20, 2021

For Dietary Supplementation "If you have low blood pressure, do not take L-theanine. I took only a single capsule and have felt lightheaded and shaky to the point that my body is trembling. I feel like I am going to pass out. I was prescribed L-theanine for my general anxiety. You would think that considering I have a history of low blood pressure, the doctor would mention it could lower my blood pressure further. I guess it is on me for not doing enough research."

2 / 10
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3 Report
  • Kmj...
  • Taken for 1 to 6 months
  • March 11, 2022

For Dietary Supplementation "So far, pretty good after a month. Taking 200 mg twice a day for stress and anxiety, with heart racing, shaking, sleeplessness. Certainly takes the edge off, but honestly, not working as well as I thought it would. I have high hopes, as I became seriously addicted to tranquilizers and antidepressants 10 years ago, and it took me a year of horror to get off them. My body simply doesn’t metabolize these drugs. So no way will I ever take another, and so hoping l-theanine will help through my anxiety, as the older I get, the more anxious I seem to become as life happens while we plan it. Thanks, everyone, for sharing your experiences."

6 / 10
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