The World’s First Open-Source Supplement Company

Most companies use "proprietary blends" so they don't have to tell you the amount of each ingredient in their formulas. At Natural Stacks we believe it's your right to know exactly what you're putting into your body. We proudly publish our innovative formulas and ingredient suppliers in an open source format. 

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01/ Caffeine and L-Theanine for Clean Energy and No Crash

Smart Caffeine is a highly effective combination of L-theanine and Caffeine. L-theanine is a natural amino acid found in green tea that removes the undesirable side effects of caffeine, creating long-lasting energy and attention without jitters, anxiety, or a crash.

The benefits include:

  • Increased focus and alertness

  • Improved cognitive function

  • Enhanced short-term memory retention

  • More ability to ignore distractions

  • No overstimulation

Smart Caffeine creates a relaxed yet alert state that is ideal for focusing and thinking clearly.

Smart Caffeine is a natural nootropic stack made from coffee and green tea to support a relaxed but alert state that is ideal for productive, focused activity - mental or physical.

The energy and motivation from the Caffeine is harnessed and smoothed over with L-theanine. The result is a focused energy state with improved cognitive function [14] that’s perfect for creative or analytical work. Best of all, there’s no jitters, no crash and no anxious feelings. [15]

Thousands of people use Smart Caffeine every day as a study aid, pre-workout, energy drink replacement or whenever they need a lift.

There have been many recent clinical trials conducted by various organizations proving that the combination of L-Theanine and Caffeine in our same 2:1 ratio increases the ability to focus without the over stimulating effects of Caffeine alone:

A recent study from The Netherlands confirmed that "The combination of L-Theanine and Caffeine improves the cognitive performance and increases subject alertness." and that the combination "helps to focus attention during a demanding cognitive task." [1]

The Cognitive Neurophysiology Laboratory in New York conducted testing for 4 days on volunteers from the age of 21 and 40 and found that L-Theanine and Caffeine in combination positively affect human cognition and caused measurable increases in alpha brain waves - the brain waves associated with alertness. [2]

A UK-based study published in Nutritional Neuroscience found that the combination of L-Theanine and caffeine improved both speed and accuracy of performance when switching between tasks (multi-tasking) and reduced susceptibility to distractions during a memory task. The researchers summarized: "These results replicate previous evidence which suggests that L-Theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks." [3]

A Dutch study gave participants L-Theanine and caffeine in the same 2:1 ratio that Smart Caffeine contains, the asked the participants to complete 2 attention tasks at 10 and 60-minutes after ingestions. The researchers stated that "The results support previous evidence that L-theanine and caffeine in combination can improve attention." [4]

A review of multiple studies published by the School of Psychology in Australia concluded that "L-theanine may interact with caffeine to enhance performance in terms of attention switching and the ability to ignore distraction; this is likely to be reflective of higher-level cognitive activity." [5]

New research from Korea has shown the amino acid L-Theanine (commonly found in tea) inhibits the excitatory effects of caffeine (you'll be less jittery) and "low doses of L-theanine can partially reverse caffeine-induced reductions in Slow Wave Sleep (the transition from wakefulness to sleep); however, effects of L-theanine on caffeine-induced insomnia do not appear to increase dose-dependently."

L-Theanine can reduce jittery effects of caffeine and helps prevent sleeplessness caused by caffeine consumption. [6]

Another study from neuroscience labs here in the US found that L-Theanine in combination with caffeine had positive effects on both tonic (background) and phasic (event-related) cognition.

In this study, participants were dosed placebo, caffeine only and caffeine + L-Theanine. The participants that received the combination of caffeine + L-Theanine demonstrated significantly greater increases in mental performance than both the caffeine-only and the placebo groups. [7]


100% Happiness Guarantee

If for whatever reason you're unsatisfied with your Natural Stacks supplements, you can keep the full bottle on us and we'll refund your money. Anything after the first bottle, we'll ask that you return for a refund.

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Based on 176 reviews
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176 Reviews
Reviewed by Jeneffer E. M.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Smart Caffeine

This product is good, I like that it's natural.

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Reviewed by Wendy C.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Best caffeine boost I've tried!

I don't drink coffee (it upsets my stomach). Using very strong black tea sometimes helps me, but it was getting to the point where I was relying completely on Extra Strength 5-Hour Energy to get through my day. I was going through a bottle a day, which adds up to around $100/month! Yikes! I am very happy with the Smart Caffeine supplement...I take it as soon as I wake up in the morning, and it gives me long-lasting quiet energy. I only rarely have to take more than one a day. Not only am I able to be more focused and productive, but I'm saving a boatload of money as well. Very grateful for this product!

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Reviewed by Thijs J.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Simple but effective

My favorite nootropic by far. Very convenient if you need an energy boost.

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Natural Stacks

Thanks, Thijs! Sustained energy without the jitters! It's great when paired with CILTEP for the ultimate nootropic stack!

Reviewed by Tellisa Hill b.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Really smart caffeine!

Helps me to concentrate and be more alert.

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Natural Stacks

Thats great, Tellisa! Clean energy from caffeine without the "jitters" is essential for concentration.

Reviewed by Travis B.
Verified Buyer
I recommend this product
Rated 5 out of 5
Review posted

Greatly helps medical work

I work in a stressful medical laboratory, and I need a boost while also staying calm. The caffeine and L-theanine blend is a great combo!

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