L-theanine User Reviews & Ratings (Page 4)

• 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."

• Jim...
• Taken for 1 to 6 months
• September 14, 2018

For Dietary Supplementation "Every time I use this supplement, I have either an intense dream or a full-blown graphic, bloody nightmare. The night before last, it was about a bloody body being dragged around and hidden in my house! This is a known side effect of this supplement. The other potential benefits, of lowering cortisol and helping me stay asleep, are all great. However, if I feel gross all day remembering the feelings of these dreams, that's not helping me be less stressed or focused during the day."

• Mil...
• November 11, 2020

For Dietary Supplementation "I took l-theanine at a 200 mg dose at 2 am in combination with 100 mg caffeine. I was hospitalized hours later. After the extreme weakness and dangerously low blood pressure it caused, panic attacks almost drove me crazy. It doesn't seem to work well for everyone."

• Pal...
• Taken for less than 1 month
• June 10, 2025

"Glad to read I am not the only one with palpitations. Heart feels like it's pumping harder, so I will have to stop. Too bad because it lowered my blood pressure really well. Haven't read anything like this, but I'm getting a yeast or bread-like smell from it too. I took 100 mg."

• Tha...
• Taken for less than 1 month
• April 26, 2021

For Dietary Supplementation "I tried supplementing with L-Theanine for stress and noticed that I was getting random heart palpitations. When I stopped supplementing, they went away. It also hides in a lot of supplements. A friend's husband had the same issue from a natural sleep product that had L-Theanine in it."

• Tra...
• Taken for less than 1 month
• March 1, 2018

For Dietary Supplementation "I had been taking 3 mg melatonin for sleep, but wanted to cut back as it left me feeling somewhat drugged. I found a product that contains 1.5 mg melatonin plus 100 mg l-theanine in a chewable, gummy form. It’s been working great for me for about a week. I feel this combo “lets” me sleep vs. “puts” me to sleep. However, I’m not sure if it’s the level of melatonin, the l-theanine, or the combo that works so well for me, but I’ll continue with it for a while."

• Dee...
• Taken for less than 1 month
• October 13, 2019

For Dietary Supplementation "Took 100 mg of L-theanine with a 20 oz coffee. Felt energetic and very focused all day long, just like it said I would. Went to sleep and remember having bad nightmares. Woke up at 4 am with the worst gas and diarrhea I ever had (to the point I thought about going to the ER). I do believe they are onto something with this drug, but the way it randomly affects each person completely differently tells me that more research is needed. It is asinine to be sold over the counter."

• Jen...
• Taken for 1 to 6 months
• September 5, 2019

"I also struggle with generalized anxiety disorder. It doesn’t usually disrupt my life in such a forceful way, luckily, but it does cause me issues with falling asleep and focusing at work. I tried taking 200 mgs at night and 100 mg in the morning, as suggested by several websites. I did this for almost two months, and I started feeling VERY depressed and had some really dark thoughts. While this does happen occasionally, it’s really usually only anxiety I struggle with. I decided to stop taking it to see what would happen; how could a supplement make me feel this way? Well, within a few days, this depression, borderline crippling dark feeling I had, totally disappeared. I took a month and tried again; smaller dose and tried a tea that also had it and experienced the same thing. Super strange... I think it’s worth a try, but monitor your moods."

• Nat...
• Taken for less than 1 month
• August 13, 2018

For Dietary Supplementation "Took this as I was suffering from anxiety and wanted to avoid prescription medication. I took this before bed, felt a little relaxed, and slept well for 3 hours. Woke up after that and could never sleep after. Don't think this is right for me, so gave up."

• 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."

• Amw...
• Taken for less than 1 month
• February 25, 2023

"I am grateful to have come across this website review page. It occurred to me, after experiencing lightheadedness, near-fainting spells, and heart palpitations for the past week and a half, that it could be related to something I was taking. I decided to search for information on L-Theanine, as I had added 50 mg of it to my nightly routine about 3.5 weeks ago to aid in sleeping, which it did. I recently visited the doctor to have an EKG and blood work done to investigate these new symptoms, but everything came back normal. However, I did notice a drop in my blood pressure from its usual 120/80 to 90/70, and my heart rate decreased from the 80s to the 70s. Upon reading the reviews, it appears that my recent issues could be linked to L-Theanine. I appreciate everyone sharing their experiences, as everyone is affected differently by various substances. Although some may benefit, others may not. I am currently grateful and have decided not to take L-Theanine tonight."

• 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."

• ONe...
• April 25, 2023

For Dietary Supplementation "I have been trying for months to find a solution for my ADHD/anxiety. My therapist recommended exercise, meditation, journaling, and eating healthy (an existing habit). After months of no improvements, we were thinking of trying rx medications, which is a fear of mine because of the side effects. Before seeing a psychiatrist, I did my own research and discovered L-theanine from a YouTuber’s video that sparked my interest. I went out the next day and bought L-theanine along with a few other supplements that were recommended, and I must say, the next day I felt completely fine, with no crippling anxiety, no overthinking, and I was more outgoing. I’m looking forward to more days like this. I hope L-theanine can help you as well!"

• Baz...
• Taken for less than 1 month
• August 17, 2020

For Dietary Supplementation "I read this supplement could help with withdrawals from fluoxetine, so I took a 400 mg dose (the only dosage I could find) with magnesium before going to bed. I slept very poorly that night (could have been unrelated, though). But the next day in the morning, I experienced a feeling of panic and rapid heartbeat that completely freaked me out. I was driving and thought I was going to black out. I don't get panic attacks or severe anxiety, so I decided to stop this supplement immediately. I would recommend starting on a very low dose if you are going to try this."

• Egg...
• Taken for less than 1 month
• October 2, 2018

For Dietary Supplementation "I began taking this about 3 weeks ago, as it had a lot of good reviews and seemed to be helpful for those with anxiety and social anxiety, which I have both of quite badly. I take 200 mg daily, a few times I have doubled it, and only one day did I feel slightly less anxious, and by slightly less, I mean barely any difference. I have not had any good results, it's like I'm not taking anything unless it's too soon to tell."

• Jac...
• Taken for 1 to 6 months
• October 15, 2021

For Dietary Supplementation "Heart palpitations within 5 minutes of taking 100 mg. This is after about one month of usage without any problems. It was providing me the benefit of a clear head, no fogginess when waking up, but the palpitations are concerning and affect sleep quality. Will try to reduce the dosage to 50 mg."

• 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."

• Maz...
• September 2, 2020

For Dietary Supplementation "So I suffer from BPD and every type of anxiety, I guess. I found l-theanine and bought 450 mg ones. Took 2 pills before sleeping. Within 30 minutes, was knocked out without the daily suicidal thoughts. Everything was going so well. However, a month later, I was perfectly fine until I had a stomach ache. I went to the toilet a number of times and nothing was coming out. The following night, I had diarrhea. The worst ever experienced in my life! It was 2:30 a.m. and my stomach didn't let me sleep, so I went to the toilet. Story short, ended up unconscious in the hallway. Once I gained consciousness, I ran to the toilet again for the other half of rapid fire. It took all my energy. Today, after 2 months, again, was laughing with Mum until I had the worst stomach ache out of nowhere. I felt my body shutting down on me. I rushed to the toilet with the same signs and rapid fire before falling unconscious. Now I know it is l-theanine, I will not try these again. Please do not try this."

• Ter...
• Taken for 1 to 6 months
• December 12, 2023

For Dietary Supplementation "I have been taking l-theanine for almost a year now with stops, of course. The longest I have taken it was about 2-3 months, every day 400mg in the morning and 200mg at lunch (if needed). I started at a lower dose but moved up quickly. It has helped me a lot. I have C-PTSD, generalized anxiety, ADHD, autism spectrum, and depression. I also suffer from PMDD. It doesn't work for every panic-anxiety-PTSD episode I get, but sometimes even diazepam doesn't help. Most of those episodes get better in half an hour, I regain the ability to think clearly again, though I still experience intense emotions. However, they stop controlling me. It doesn't help me with sleep though, I actually get quite active. I can honestly say that l-theanine is saving me from addiction to benzodiazepines. Now I only take diazepam about 2 out of 10 times I have breakdowns. It doesn't give me brain fog, it actually lowers my heart rate (I have 90BPM almost constantly). The only issue I have with it is that it only works for 4 hours."

• Anonymous
• August 6, 2021

For Dietary Supplementation "100 to 200 mg 3 times a day helps me with generalized anxiety disorder. I also have powdered form. 1/8 tsp under my tongue relaxes my brain. Lowers cortisol at night for better sleep. Tapering off gabapentin with l-theanine and melatonin before bed. God bless, keep looking forward."

• Car...
• Taken for 1 to 6 months
• October 23, 2023

"I started it around June after doing extensive research on it online. I was going through a very stressful time in my life at the time multiple stresses in my life. Cancer scare with my mom relationship issues due to being unemployed. I started the drug end of June, it started working only after about 3 days. I don't know what it took so long to work. I started with 400 in the morning then started 600 mg every morning. I found that if you didn't eat something with it, it made me very sick. I read later that it had to do with the fact that it is an amino acid, so it messes with your stomach acid causing you to get sick if not taken with food. It saved my life after that. I was very close to checking in somewhere due to the constant paranoia and fear. It was literally driving me insane, being in a constant state of fear. I felt disconnected and not myself. It made things go away in almost a strange way. I remember driving and suddenly it didn't feel anxious anymore."

• 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."

• 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."

• RJA...
• Taken for 1 to 6 months
• February 2, 2022

For Dietary Supplementation "Micro dosages. Hi - I posted last year explaining how well I felt after drinking green tea. However, 40 mg-200 mg of the supplement made me feel very uncomfortable (mentally and physically). I also mentioned giving microdosing a go. I have been taking tiny amounts of the supplement in powder form at night and in the morning for 2 months, and it has done me wonders."

• 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."