Caffeine and Theanine Capsules

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What is Caffeine?

Caffeine is a potent stimulant obtained from coffee beans or manufactured in a lab. Caffeine works by blocking adenosine from its receptors. Adenosine causes drowsiness, so inhibiting it results in prolonged alertness [1]. It is the most widely consumed stimulant in the world [2].

Caffeine Benefits

While its primary use is as a wakefulness enhancer, caffeine has additional benefits including improving endurance, stimulating fat loss, and as a nootropic.

Caffeine and Endurance

Caffeine is able to improve endurance in both anaerobic and aerobic exercises. Its anti-fatigue effects delay the onset of muscle fatigue during anaerobic workouts, allowing you to work longer [3]. It is also able to improve endurance performance during aerobic workouts, meaning it lengthens an individual’s time to exhaustion [4]. These effects are more pronounced in non-habitual caffeine users [5].

Caffeine and Fat Loss

Caffeine can reliably increase metabolic rate, which in turn helps to burn more calories. In one study, all participants were able to lose weight when they combined caffeine with a low-calorie diet [6]. However, caffeine tolerance develops quickly, so it is suggested to use caffeine intermittently for maximum results.

Caffeine as a Nootropic

While there is some debate as to whether caffeine is a true nootropic, it is able to enhance alertness, concentration, and short-term memory [7]. It is also able to enhance reaction time, particularly in situations of sleep deprivation [7].

What is L-Theanine?

L-Theanine is an amino acid found in most teas used for relaxation without sedation. Its structure is similar to that of glutamate, an excitatory neurotransmitter. It has been studied for its neuroprotective benefits as well as its ability to enhance cognition, improve learning and memory, and reduce stress [8,9].

L-Theanine Benefits

Theanine’s main benefit is its ability to induce relaxation. That being said, it also provides stress-relief and nootropic benefits.

Theanine and Relaxation

Both neural measurements and self-reported assessments attest to l-theanine’s efficacy as a relaxation agent [10,11]. It is also able to do so with relative speed, taking effect within 30 minutes to an hour [10,11]. What sets theanine apart from other relaxants is its ability to induce relaxation without drowsiness [12].

Theanine and Stress

There is much research dedicated to L-Theanine’s stress reduction benefits in both animal and human studies. Theanine is able to reduce corticosterone in rats and salivary IgA in humans, both of which are biomarkers to stress [13,14]. In the rat study, theanine was able to reduce stress both with and without active stressors. [13]

Theanine as a Nootropic

Some of theanine’s nootropic benefits directly correlate to its ability to reduce stress. It is a well-documented fact that corticosterone and stress exert negative effects on memory [15,16]. By reducing the biomarkers of stress and stress itself, theanine is able to improve memory. Independent of its stress-reducing benefits, theanine is also able to improve delayed recognition and recall in individuals with mild cognitive impairment. [17]

Why L-Theanine and Caffeine Capsules?

While it may seem counterintuitive to combine a stimulant with a relaxant, theanine and caffeine are a unique mix. Theanine is able to attenuate the negative effects of caffeine (headaches and jitters) while simultaneously improving alertness, reaction time, and working memory [18]. This combination provides smooth, focused energy without the drawbacks commonly associated with stimulants and relaxants.

Caffeine and Theanine Powder vs. Capsules

Caffeine and theanine are available in both bulk powder and capsule form. While one method of supplementation is not more effective than the other, capsules are much more convenient. Caffeine and theanine capsules provided pre-measured dosages that remove the tedium of measuring your supplements every day.

L-Theanine and Caffeine Dosage

Theanine and caffeine are most often used in a 2:1 ratio. Each capsule contains 200mg of theanine and 100mg of caffeine. For best results, individuals should take 1 theanine and caffeine capsule per day.

Curated Reviews

So these are great. They aren't big capsules. The caffeine : l-theanine ratio of 1:2 is considered fairly optimal for most people. If I had to choose an amount of caffeine I would want in one dose (one pill), I would have chosen pretty close to 80mg, which is what these provide (100mg is too much for me, 50mg too low). You may be different, but in any case, they're 5 stars for me. I take them to the coffee shop because all my other noots are free powder form.– Christopher C.

"So I've been taking these caffeine & theanine capsules every morning for the past few days, along with an ALCAR capsule. Both these capsules are cheap and they work very well together for me. I get higher energy level and a mood boost too. Compared to other much more expensive nootropics this works really well. Perhaps the best 'stack' you can get on a tiny budget. I add some Oxiracetam to this stack and if I'm ever sleep deprived one Sulbutiamine capsule added to this stack puts me on top of my game. However I find this is only required in rare cases. 1 x Caffeine + Theanine capsule & 1 x ALCAR capsule = great energy and mood. I take one on waking up. Then at lunch time."- Quinn

"I'm a 50 year old male who does Brazilian Jiu Jitsu. I like to use this product about an hour before class. It doesn't make me shaky or make my heart rate elevate that I notice. I'm 5'10 and weigh 180lbs - I only take 2 before I get on the mats. I've taken 3 but felt a bit nauseated after rolling for 2 hours. That may have been due to something else though. But I find 2 works well for me. Will order again."– James H.

"Very new to nootropics and heard that l-theanine and caffeine was a good starter. Used it for a good 2-3 weeks and it gives you that boost in the morning. You don't get jitters from the caffeine and you feel focused. It's hard to notice the effects because they are quite subtle. Overall, excellent product and would recommend to anyone new to nootropics or want to focus without drinking coffee. Although nothing beats the taste and smell of coffee in the morning."– Vincent F.

"I love caffiene and like many at times over indulges. I learned about Theanine balancing caffiene and would often take some when I've had too much caffiene. To put it together beforehand as a balanced, clean energy that is almost unnoticeable. I'll take 2 caps in the mid afternoon when I might reach for a cup of jo and get so much work done and don't really notice a change in my energy most of the time."– Tim T.



Additional Resources

Theanine Examine Page
Caffeine Examine Page
Caffeine Wiki
Theanine Wiki


Review guidelines


Statements found within have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. Consult with your physician before taking if you are pregnant, nursing, have any cardiovascular or other medical issues, or anticipate surgery. Keep out of the reach of children.

Scientific studies cited are not conclusive and have limitations, due to of their closed environment nature. Referenced studies will not necessarily determine your experience with a supplement or nootropic, since there are many unaccounted variables, which fall outside the scope of the studies.

The reviews contained within are the opinions of contributors and are not necessarily the views or opinions of Powder City. These reviews should not be taken as fact or recommendation, and are only opinions of products that the contributors may have or may have not used. Powder City makes no warranty, implied or expressed, to the accuracy of information provided by these reviews.


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