Bulk Supplements always works for me. Easy to mix, tastes fine. You can easily mix into a beverage or just plain water. Totally takes the edge off. Use for sleep at night every night and occasionally during day for high stress moments. Chills me out without any cognitive impairment. Always buy this from this brand. Great deal.Helps me go to sleep and stay asleepI just got my first order of Theanine from this specific seller (BulkSupplements) and am very happy with what I got.I use L-Theanine for mental function and I combine it with caffeine. I find it is useful in helping me focus and that with a larger dosage of caffeine (especially caffeine from guarana extract) that the effects are very pronounced. I can stay on track of tasks, sharply focus, and especially feel I work better with numbers. As all of our bodies are different and the same medication has different outcomes with different people, I cannot say if Theanine will be effective for you or not when used for this purpose. With that said, the User reviews here (and elsewhere) show that there is a pretty sizable chunk of people who have had luck using Theanine (combined with caffeine) for improved mental function.In terms of the science behind L-Theanine, the research is varied and not nearly as vast as many other supplements used for improved mental functioning. Some research has suggested Theanine has some degree of usefulness for anxiety, hyperactivity, sleep, the immune system, and mental performance. I use the word "some" because the results of clinical research has varied. Given how the same drug will affect different people in a different manner, this isn't all that surprising to see a limited number of controlled trials yield variable findings. With that said, User reviews show that Theanine has been extremely successful for some people (myself included) and so I think this is a supplement that holds potential value. Note that most of the studies which have found beneficial effects for reaction time and memory have also utilized caffeine alongside Theanine, as these two drugs seem to have synergistic effects in potentiating each other. I do not personally get any notable benefit from Theanine without simultaneous usage of caffeine.In terms of safety, I think it is always important to be aware of what goes in the body, and to be sure that what goes in our bodies come from trustable and respectable suppliers. Another Reviewer asked the question of 'how can one know they are getting real Theanine?' It's a fair question, and this is how I went about answering that question...In terms of 'knowing' if it is Theanine, I know because the difference for me is tremendous and very pronounced: for me, it takes the stimulant side of caffeine and somehow funnels it into mental sharpness. Caffeine alone does not do this, nor has any other supplement I have used for improved mental function. In terms of knowing if the product is safe and pure, I spent some time looking at different suppliers and reviews for their company and for the products they sell. I feel that this company, Bulk Supplements, has one of the best reputations on all of Amazon. Their general transaction feedback is excellent (like 99% positive), and virtually every product they sell has outstanding reviews. These thousands of stellar reviews made me feel that Bulk Supplements was a great choice to go with, and now having the product I can say I am very happy with what they sent me. So I am not sure if that is beneficial for you, but for me it was the deciding factor in buying Theanine from Bulk Supplements over other companies. I will certainly be purchasing from them in the future and I highly recommend them as a company to buy from.This Theanine (and other supplements in bulk) go along really well with a scale and a machine for making pills. As this comes in bulk powder, dosing quantity using a scoop is not the most reliable means and being able to weigh the dose is a much more consistent route. I purchased an AMW scale a few years ago for under ten bucks, so a decent-quality scale can be had for a very low price. I also own the Capsule Machine which I use to make capsules from bulk powder supplements. While there are tons of different makers producing those kinds of products, I figured I would mention those two as I purchased both on Amazon and can say first-hand that I am very happy with each. Having this scale and capsule machine makes using supplements much easier for me.So overall, I have had really good results with Theanine, and I am very happy with the Theanine that Bulk Supplements delivered on. While I cannot say if Theanine will be helpful for you or not, I can say that this is a Seller with good-quality Theanine in a pure form, and for a very reasonable price.After reading someone's review on how it helped so much, I do this. I couple this with "GABA" capsules. I use maybe 1/2 teas. as this is "bulk powder" but a better price. It is tasteless. But you can buy capsules instead. (vitacost has them, I buy the GABA there). do your research. can't say here......"I'm no doctor, blah blah blah". ;)I have anxiety and a mix of ocd, bruxism and misophonia. I began l theanine when my chiropractor suggested it. It was the only thing, a doctor visit, dental visit that they ground my teeth down a bit to try literally anything; even a mouthguard and cutting caffeine out did not help. I used to have to take 3 or 4 aspirin and put biofreeze on my face and neck just to Cope with the pain. I began mega dosing l theanine capsules and it became annoying to take so many capsules of this Amino acid so I eventually searched for a powder. Through my experience with l theanine I began to give my cats l theanine treats from pet smart, at first for a 14 hr moving trip and continued for behavior indicated by my senior cat as anxiety. I noticed a big improvement with my cats as well. I bought this large bag of bulk loose l theanine and liked that it was still 1 mg per 250 dose. I usually end up taking between 1000-3000mg a day depending on the day. It isnt a depressant which is great for staying the day; it blocks glutamate and prevents your body from experiencing fight or flight in the first place. It really, really helps with my tongue thrusting (pushing my tongue against my bottom teeth subconsciously throughout the day) and with my night time bruxism. It greatly lessens behavioral accidents with my senior cat. This bag of loose bulk amino acid really cut the annoyance and cost down for me. It tastes like semi sweet powdered sugar or stevia maybe. I put some on a banana yesterday in a pinch and enjoyed it surprisingly. Usually I will shake about 4-5mg in a shaker bottle with water and put it in my cats water dish (surprisingly they don't seem to notice and drink it as usual) and then I'll put around 8 to10mg in my protein shake. I love caffeine but it tends to worsen my anxiety mixed issues, thankfully, l theanine works with caffeine, taking the edge off the anxiety or jittery feelings some experience, and it boosts the concentration from caffeine for a good morning kick while simultaneously calming you down. Anyway sorry for going on but I will be subscribing to this product and I can't suggest it enough (especially for BRUXISM/tongue thrusting issues and pet anxiety/marking territory due to anxiety).