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L-theanine User Reviews & Ratings (Page 5)

L-theanine has an average rating of 5.3 out of 10 from a total of 143 reviews on Drugs.com. 45% of reviewers reported a positive experience, while 45% reported a negative experience.

Reviews for L-theanine

Commonly mentioned side effects
  • Jay...
  • Taken for less than 1 month
  • November 23, 2021

For Dietary Supplementation "Took 225 mg before bed for several nights in a row (4 or 5 maybe). I did sleep well and had vivid dreams. I noticed my premature atrial contractions that I have had diagnosed previously were especially frequent and bothersome. I have had them now and then my whole life, but they are only frequent and dizzying under periods of extreme stress and fatigue, which I am not experiencing right now. I didn't correlate the two until I found others reporting palpitations. Unfortunately, I haven't taken theanine in a couple of weeks, but the problem persists. Obviously, I can't say for sure it caused the problem, but it is the only change in my routine that I can correlate it with. It hasn't gone away with cessation of the supplement, though. 225 mg is quite a high dose apparently. Be careful and start with 50 mg if you are going to try it."

4 / 10
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  • Sto...
  • Taken for less than 1 month
  • March 8, 2023

For Dietary Supplementation "Decided to try this to help with minor anxiety - not interested in taking prescriptions. Started with 400 mg/day (200 mornings, 200 evenings), felt good, and was generally stress-free for a few days but wanted to see how I'd do with 300/300 mg a day (600 mg total for a day). I'm 6'4", 200 lbs. Found myself having a strange reaction one night with very low blood pressure and could literally feel my breathing getting way too shallow. I already have low blood pressure. Backed off of this and only did 200 mg in the morning, cut way back on caffeine, and feel much better. Just be careful if you go above 400 mg/day. Also, the half-life of l-theanine is very long and stays in your system for a while, so keep this in mind. Overall, I do recommend l-theanine if you know what you're doing."

9 / 10
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  • Mic...
  • Taken for less than 1 month
  • June 30, 2022

For Dietary Supplementation "After reading the reviews, I ordered a bottle of 200 mg l-theanine capsules for anxiety, and I just took one early this morning. I didn't read anything about it needing time to take effect, but it's been about 5 hours now, and I don't feel less anxiety at all. I also don't feel productive or clarity of mind, I feel my usual burnout and chaotic mind. I just have this weird feeling in my head like the beginning of what might later be a headache, so I took some ibuprofen to avoid that. I took this capsule specifically today because I'm having irritability and a hard time functioning and getting things done. I guess if you didn't have a bunch of demanding and inconsolable children you're caring for, then this may feel like it works. Has anyone tested this with kids screaming and yelling in the background and constantly asking for things and being dissatisfied? I doubt it. I'm also having back pain from tensing up, but that might just be my anxiety."

1 / 10
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10 Report
  • Lyn...
  • Taken for 1 to 6 months
  • August 22, 2023

For Dietary Supplementation "I can't remember if I posted about this before so apologies. I've been taking 350mg once a day. I split the second 200mg powdered capsule in half. I'm trying to self-wean off my benzos as I've developed resistance and they're not effective anymore. Do not mix the two! I feel calmer and more sedated. I do get quite groggy, but I'm calm and everything just melts away without any side effects. I can handle things better. The only thing I'm worried about is my racing heart, developing resistance to it, and the vivid dreams. I'll give it more time to see if my anxiety (like racing thoughts, panic attacks and thoughtless rambling) and PMDD symptoms continue to improve. Last cycle was milder and it surprised me. I refuse to go on hormones or try another SSRI. I threw that trash Paxil in the garbage. L-Theanine seems to be working out. My cortisol hormone levels were high and I just got my blood tested last week. I was told they lowered. I'm so happy to hear that."

8 / 10
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  • MrT...
  • Taken for less than 1 month
  • August 22, 2021

For Dietary Supplementation "I was very skeptical of a supplement doing anything for my anxiety/panic, which has been pretty strong, like a nervous breakdown. I wanted to avoid SSRIs (bad experience in the past), and therapy hadn't helped. Well, I'm shocked at how powerful L-Theanine has been. I've been taking a big dose (350 mg tablet x3 a day), and it feels like I'm taking diazepam, just without side effects or withdrawals. A zen-like blanket of the mind. The worry thoughts are still there, but it's like you float through them. Hard to describe... a warm fuzzy feeling a bit like a tab of acid (from my younger days). If you're a cynic like me, try it, definitely before your doctor puts you on a hard drug."

10 / 10
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  • Kir...
  • Taken for 1 to 6 months
  • May 7, 2023

For Dietary Supplementation "Researching these types of supplements is a good idea before popping pills left and right. Some medications can interact with supplementation. One size does not fit all, and if you are taking prescription medication, a negative drug interaction can occur. I have an uncle that cannot eat seafood, if he does, his entire body will break out in a rash, and he will need to get to an ER ASAP. Everyone is different. Experimenting with nootropics, I have sought to underdose and skip days. I have found positive effects from these types of supplements. L-Tyrosine and L-Theanine are similar but different. I would suggest you wear your seatbelt, research, and tread carefully on the freeway of nootropic supplementation. Do what you gotta do. Follow doctor's advice."

8 / 10
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  • 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."

5 / 10
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  • Iss...
  • Taken for less than 1 month
  • October 10, 2021

For Dietary Supplementation "I've had sleep issues for the past week since stopping smoking cannabis. I took nutritional advice at a health food shop and bought L-theanine and Serotonin 5-HTP. I took one each of the capsules shortly before going to bed last night, following the directions on the bottles. I had a terrible night with stomach pains and nausea, and then a headache developed. These symptoms have remained more or less constant, with a slight reduction for a time after taking paracetamol. It is now 4:25 PM. I will not be taking either of these supplements again."

1 / 10
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  • Hap...
  • Taken for less than 1 month
  • December 21, 2022

For Dietary Supplementation "Since combining L-Theanine with Magnesium Taurate, I didn’t have the need to take my beta blocker (metoprolol) anymore. I did have to taper off metoprolol for good measure since it can be dangerous to stop taking it suddenly."

8 / 10
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  • 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."

8 / 10
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  • lau...
  • Taken for less than 1 month
  • January 5, 2021

For Dietary Supplementation "Took 100 mg of l-theanine and got a headache about two hours later, along with some brain fuzziness. Not entirely miserable, but definitely not desirable. Not sure if I've felt noticeably calmer or more focused."

3 / 10
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  • Ind...
  • Taken for 1 to 6 months
  • May 18, 2023

For Dietary Supplementation "I’ve taken it twice with different responses. First time: 400 mg in the daytime, and it sent me absolutely doo-lally, and I was totally hyper manic. I couldn’t settle. Three years later, I tried it again at 400 mg in the daytime. It was a last resort as I was totally sleep-deprived/stressed and thought, “I’ll try anything.” Within an hour, I had to lie down and take a three-hour nap. I then used it over a period of two months. First as an ad-hoc sleeping aid. I find it doesn’t lengthen sleep much, maybe an hour, but the quality of sleep is higher. There can sometimes be what feels like mild grogginess, but it is easily overcome by just doing something. Then I’m pretty productive, can hammer through mundane tasks with ease, and stay on track with routine computer work. A great benefit was in tapering off caffeine (50-100 mg per mug) - pretty much removed all side effects. The only difference I can see was an underlying infection the first time around."

9 / 10
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  • Jen...
  • Taken for less than 1 month
  • April 5, 2022

For Dietary Supplementation "I am an 18-year-old female, and I have tried the l-theanine and caffeine combination many times to help with my ADHD and mild anxiety, but it has zero effect on me, whether I take it on an empty stomach or not. I tried upping the dose, still, no results."

1 / 10
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  • swi...
  • Taken for less than 1 month
  • August 2, 2021

For Dietary Supplementation "I felt so spaced out, couldn't really work. I got focused on doing all kinds of things I've wanted to do for a long time, but not work. I couldn't calm down in the evening, had this urge to get stuff done, organize things, etc., very unpleasant. Somehow made me a little bit calm, but mostly way too over the place to get anything done sensibly. Now I feel exhausted after a few days of it, feel as if I'd have been on drugs for a few days."

2 / 10
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  • 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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  • Rom...
  • Taken for less than 1 month
  • November 25, 2021

For Dietary Supplementation "Started taking 100 mg to help fall asleep, and it worked great, took it about 30 min before bed. But then I began to realize additional muscle fatigue and stopped taking it. As with all supplements, they are trial and error. Did not notice any other side effects."

4 / 10
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  • Lyn...
  • Taken for less than 1 month
  • July 21, 2023

"I tried this as recommended by a herbalist at my local health food store as I'm very hesitant to take other psychiatric medication. He said not to mix it with benzos. I only took one a day, 200 mg. This gave me the calmness and peace I was looking for but I had no memory whatsoever. I would forget conversations and it was quite awkward. I would have horrific night terrors. My klonopin had stopped the nightmares, so I'm only taking them during my PMDD week. They do help calm me down to the point of feeling doped-up sedation and they kill my appetite. Consult your doctor if you decide to try this. I love/hate this supplement."

7 / 10
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  • 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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  • Jwc...
  • Taken for 1 to 6 months
  • May 22, 2022

For Dietary Supplementation "Diagnosed in the early '90s with ADD as a kid, docs tried me on all the usual suspects, made me a zombie kid, I hated it. 30 years of non-medicated personal mind battle later, and I learned about L-theanine. I take 200 mg in the morning and again after dinner. First dose ever, after 30 min or so, it was like the dust cloud in my head settled and the uncontrolled randomness of my otherwise frolicking mind just kind of chilled out. Not some voodoo miracle, but a legitimately settled and amiable thought process for me. Unfortunately, about 4 weeks in, and I believe it to be causing a pretty low-grade but almost constant nausea with an unsettled but not painful stomach. I am going to stop for a few days/week to confirm my experience. I do not notice any real boost when combined with caffeine, but I may tinker more. I don’t drink coffee, so I may need more caffeine content. I may try a different brand of L-theanine also, I really feel it helped me in a life-altering way as long as I can beat the nausea."

8 / 10
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  • Dav...
  • Taken for less than 1 month
  • September 8, 2021

For Dietary Supplementation "I'm surprised I haven't heard of L-Theanine before now. With an anxiety disorder and insomnia, I worry a lot and, as a result, don't sleep well, if at all. I've been taking 200 mg at bedtime (only), and it definitely helps to slow 'the wheels,' but it doesn't do much for sleep. So I add a Benadryl 25 mg, and that does the trick. Since I don't like taking the Benadryl every night, I ordered a bottle of Passion Flower to see if that will help. I've been on this routine for about 2 weeks. I should add that, even though I'm not bothered much by anxiety lately - except for later in the afternoon - I do have a kind of fogginess in my head all day... like having a wad of cotton in my skull instead of a brain. Maybe it's the Benadryl."

7 / 10
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  • Rac...
  • Taken for 6 months to 1 year
  • July 6, 2016

For Dietary Supplementation "I have been taking this for about 6 months after being diagnosed with Generalized anxiety. This stuff is a lifesaver. I'm not worrying all the time and I can actually relax. Definitely worth trying!"

10 / 10
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  • Mic...
  • March 6, 2015

For Dietary Supplementation "I take anywhere between 200 to 2000 mg's (Yes, 2 thousand milligrams/2 grams) and it works wonders for anxiety, panic, and stress in general. Great with caffeine too."

10 / 10
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112 Report
  • Gen...
  • June 29, 2016

For Dietary Supplementation "I had terrible anxiety and insomnia, since taking l-theanine I have no anxiety and I now have no issues sleeping. For me, it has been amazing."

10 / 10
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90 Report
  • KD7...
  • March 25, 2014

For Dietary Supplementation "I take theanine with my morning coffee - it cuts out any jitters and goes well with caffeine. I mix approximately 250 mg L-Theanine powder into the drink."

9 / 10
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107 Report
  • Bna...
  • Taken for less than 1 month
  • September 22, 2016

For Dietary Supplementation "So much better than Prozac or Zoloft. No side effects."

10 / 10
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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.

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