Caffeine + L-Theanine - The Ultimate Beginner Nootropic
The world of nootropics is as vast as it is complex, and while that might be a turn off for some folks. I just can’t get enough of them.
Nootropics are my jam, but not everyone feels comfortable spiraling down the rabbit hole that is the nootropics cosmos.
Fear not, because today, we’ll discuss one of the best beginner nootropics stacks there is on the market in the combination of caffeine and L-theanine.
Related - Complete Guide to Caffeine
Caffeine is the stimulant (drug) of choice for a considerable portion of the population, and for good reason -- it’s well studied, relatively safe (when consumed in appropriate doses), and benefits both mental and physical performance. But, not everybody responds well to caffeine on its own.
That’s where theanine comes in, and the magic of the caffeine-theanine stack takes off.
But, let’s not get ahead of ourselves.
Let’s first begin by discussing what caffeine is and how it works.
What is Caffeine and What Does It Do?
Caffeine is a methylxanthine naturally occurring in a number of plants, including coffee, coca, tea, and guarana. Other members of the xanthine family include theobromine and theophylline. 
As you’re likely aware caffeine (as well as its xanthine relatives) stimulate the central nervous system, increase mood, and boost arousal and concentration.
What you might not be aware of is how they do this.
Caffeine and it's ilk function primarily as adenosine receptor antagonists.  Adenosine is an inhibitory (“downer”) neurotransmitter that can depress CNS firing when it binds to the adenosine receptor in the brain by inhibiting dopamine and glutamate release. 
This leads to relaxation and increased feelings of tiredness, drowsiness, and fatigue, which promote sleep.
Caffeine is structurally similar to adenosine and can bind to adenosine receptors in the brain, thereby preventing adenosine from binding, leading to increased feelings of alertness, energy, and arousal.
Caffeine also stimulates dopamine release and potentiates the effects of dopamine receptor stimulation. [4,8] As you probably know dopamine is commonly referred to as the “reward” molecule in the brain and serves a critical role in mood, motivation, and motor control.
This is why your morning cup of coffee, energy drink, or serving of pre-workout not only boosts your energy levels, but also your mood and motivation, giving you the proverbial “kick in the pants” to get moving and get work done -- in the gym or in the office.
Combined, these effects are also why caffeine is a great productivity supplement and has been noted in research to improve learning, memory, and reaction time as well as cognitive performance in sleep-deprived individuals, even when doses are as high as 600mg! [5,6,7]
But that’s not all caffeine does. It can also: 
- inhibit different phosphodiesterases (PDEs),
- modulate GABA receptors (this is important, hint hint), and
- promote calcium release from intracellular stores.
Phosphodiesterases are a family of enzymes that degrade cAMP (cyclic adenosine monophosphate) and cGMP (cyclic guanosine monophosphate). 
PDE inhibitors have been extensively studied for their ability to treat a wide range of conditions including everything from asthma to cardiovascular disease and even erectile dysfunction (Viagra is a PDE-5 inhibitor, FYI).
GABA is the body’s main inhibitory neurotransmitter which reduces neuronal activity to cause relaxation and sleep. Interestingly, chronic caffeine intake can increase the amount of GABA receptors in the brain, but actually decrease the release of GABA, which is why supplementing with caffeine promotes wakefulness and doesn’t cause drowsiness. [9,10]
Since caffeine inhibits GABA release, less GABA and more glutamate is in circulation, which means that greater neuronal activity and excitation occurs. However, when the delicate balance between glutamate and GABA is off-kilter, you may start to feel anxious, jittery, and on edge. [11,12]
Consuming too much caffeine can easily lead to jitters, anxiety, or overstimulation making that energy boost all for naught as your too jacked up to be able to channel that energy into something productive.
Beyond that, for certain individuals, using too much caffeine or consuming it too close to bedtime can seriously mess up their sleep -- impairing recovery and compromising both mental and physical performance the next day.
If you’re someone that’s uber-sensitive to caffeine, or an individual that’s used just a wee bit too generous of a serving of pre-workout, there’s help on the way in the form of L-theanine.
What is L-Theanine?
L-theanine is a non-proteinogenic amino acid found prevalently in the leaves of Camellia sinensis (green tea) that can help take the “edge” off of caffeine.
Like caffeine, l-theanine readily crosses the blood-brain barrier where it gets to work stimulating various receptors in the brain, except instead of exciting neurons, L-theanine has a calming effect on the brain.
You see, theanine is structurally similar to glutamine (the precursor to both glutamate and GABA) and has been shown to inhibit synaptic release of glutamate while increasing levels of serotonin, dopamine, and GABA. 
L-theanine also increases alpha brain waves, which promotes relaxation without sedation as well as creative thinking. 
Theanine may even improve memory too as some research indicates that theanine boosts BDNF (brain-derived neurotrophic factor). 
BDNF is a protein belonging to a family of growth factors that supports the survival of existing neurons while simultaneously promoting the growth and differentiation of new neurons. Essentially, you can think of BDNF as a type of fertilizer for your neurons.
Theanine is also able to help limit the vasoconstrictive actions of caffeine on blood vessels in the brain. In case you weren’t aware, caffeine can cause blood vessels to constrict, which is why it’s frequently included as an ingredient in migraine and headache medications. 
Research has shown that adding theanine to caffeine helps reduce the number of headaches individuals have and other studies suggest it may help reverse reductions in slow-wave sleep caused by caffeine. 
As an added bonus, unlike many other nootropics, L-theanine is incredibly well studied, has no alarming side effects, is considered GRAS (generally regarded as safe) by the FDA, and even high doses show no signs of toxicity in animal studies. 
At this point, you’re no doubt wondering how the combination of caffeine and theanine could possibly be effective for productivity as it seems the two compounds have opposing actions in the body.
Yet, research finds the two to be highly synergistic...
The Magic of Caffeine + L-Theanine
The combination of caffeine and theanine (which easily could be considered “The Odd Couple” of the nootropics world) actually is extremely effective together. While they have opposing actions to a certain extent, combining caffeine and theanine may actually increase the benefits of both compounds.
Studies have found that the combination is effective for enhancing focus and sustaining it. [19,20] It’s also been noted to improve accuracy on attention-switching tasks and reduce the likelihood of distractions when performing memory tasks.
Other research notes that the dynamic duo significantly improves reaction times and acute attention (as assessed by measuring the amount of time it takes subjects to respond to flashing lights on a computer screen). [19,21]
Essentially, theanine helps “refine” the energy burst of caffeine and take some of the “teeth” out of its energy surge. This may benefit those who tend to feel overwhelmed, anxious, or jittery when ingesting anything containing the consummate stimulant, and it also has the added benefit of enhancing the cognitive, focus-boosting properties of caffeine.
What’s the Right Dose of Caffeine + L-Theanine?
Now, here’s where things get sticky with nootropics. Most of the studies to date show that the caffeine to L-theanine ratio must be 1:2.
So, if you took 100mg of caffeine (the amount in your average strong cup of drip coffee), you’d want to take 200mg of theanine.
Other studies have shown that a dose of 75mg caffeine to 50mg theanine can be effective. 
However, everyone’s neurochemistry is a bit different and depending on what nootropics you’ve previously used (and for how long you have used them) might alter your own “ideal” caffeine to theanine ratio.
Take me, for example.
If I do a 1:2 caffeine to theanine ratio, I get no energy or enhanced focus at all, and frankly feel quite tired and unmotivated. And, several other studies have also found no benefit on alertness with the combination of caffeine and L-theanine, most likely due to theanine having too much of a taming effect on caffeine’s stimulatory properties. [20,22,23]
That being said, I have found benefit when dosing the pair at a 1:1 ratio or 2:1 ratio (200mg caffeine to 100mg theanine), or foregoing theanine altogether and just riding solo with caffeine.
(I’ve never been super sensitive to caffeine and respond equally well to both low and high doses of the stimulant, hence my comments earlier about the individual differences regarding neurochemistry and nootropics dosing).
If this is your first experience with nootropics, it’s always best to start on the low end and work your way up. You might want to try an even 100mg to 100mg pair and see how you react and then adjust each up and down accordingly.
Of all the nootropic combinations on the market, the caffeine + theanine stack has been shown to be effective in multiple human studies, and it’s also extremely affordable. All it requires on your part is some experimentation to find your own ideal dose.
1) Franco R, Oñatibia-Astibia A, Martínez-Pinilla E. Health benefits of methylxanthines in cacao and chocolate. Nutrients. 2013;5(10):4159–4173. Published 2013 Oct 18. doi:10.3390/nu5104159
2) Ribeiro, J. A., & Sebasti, A. M. (2010). Caffeine and Adenosine, 20. https://doi.org/10.3233/JAD-2010-1379
3) Boswell-Smith V, Spina D, Page CP. Phosphodiesterase inhibitors. Br J Pharmacol. 2006;147 Suppl 1(Suppl 1):S252–S257. doi:10.1038/sj.bjp.0706495
4) Volkow ND, Wang GJ, Logan J, et al. Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain. Transl Psychiatry. 2015;5(4):e549. Published 2015 Apr 14. doi:10.1038/tp.2015.46
5) Institute of Medicine (US) Committee on Military Nutrition Research; Marriott BM, editor. Food Components to Enhance Performance: An Evaluation of Potential Performance-Enhancing Food Components for Operational Rations. Washington (DC): National Academies Press (US); 1994. 20, Effects of Caffeine on Cognitive Performance, Mood, and Alertness in Sleep-Deprived Humans. Available from: https://www.ncbi.nlm.nih.gov/books/NBK209050/
6) Sherman SM, Buckley TP, Baena E, Ryan L. Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day. Front Psychol. 2016;7:1764. Published 2016 Nov 14. doi:10.3389/fpsyg.2016.01764
7) Ryan, L., Hatfield, C., & Hofstetter, M. (2002). Caffeine reduces time-of-day effects on memory performance in older adults. Psychological Science, 13(1), 68–71. https://doi.org/10.1111/1467-9280.00412
8) Solinas, M., Ferré, S., You, Z.-B., Karcz-Kubicha, M., Popoli, P., & Goldberg, S. R. (2002). Caffeine Induces Dopamine and Glutamate Release in the Shell of the Nucleus Accumbens. The Journal of Neuroscience, 22(15), 6321 LP – 6324. https://doi.org/10.1523/JNEUROSCI.22-15-06321.2002
9) Shi D, Nikodijević O, Jacobson KA, Daly JW. Chronic caffeine alters the density of adenosine, adrenergic, cholinergic, GABA, and serotonin receptors and calcium channels in mouse brain. Cell Mol Neurobiol. 1993;13(3):247–261. doi:10.1007/bf00733753
10) Isokawa M. Caffeine-Induced Suppression of GABAergic Inhibition and Calcium-Independent Metaplasticity. Neural Plast. 2016;2016:1239629. doi:10.1155/2016/1239629
11) Rogers PJ, Hohoff C, Heatherley SV, et al. Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption. Neuropsychopharmacology. 2010;35(9):1973–1983. doi:10.1038/npp.2010.71
12) M J SHIRLOW, C D MATHERS, A Study of Caffeine Consumption and Symptoms: Indigestion, Palpitations, Tremor, Headache and Insomnia, International Journal of Epidemiology, Volume 14, Issue 2, June 1985, Pages 239–248, https://doi.org/10.1093/ije/14.2.239
13) Nobre, A. C., Rao, A., & Owen, G. N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 17 Suppl 1, 167–168.
14) Tamano, H., Fukura, K., Suzuki, M., Sakamoto, K., Yokogoshi, H., & Takeda, A. (2014). Advantageous effect of theanine intake on cognition. Nutritional Neuroscience, 17(6), 279–283. https://doi.org/10.1179/1476830513Y.0000000094
15) Nathan, P. J., Lu, K., Gray, M., & Oliver, C. (2006). The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent. Journal of Herbal Pharmacotherapy, 6(2), 21–30.
16) Dodd FL, Kennedy DO, Riby LM, Haskell-Ramsay CF. A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood. Psychopharmacology (Berl). 2015;232(14):2563–2576. doi:10.1007/s00213-015-3895-0
17) Jang, H.-S., Jung, J. Y., Jang, I.-S., Jang, K.-H., Kim, S.-H., Ha, J.-H., Lee, M.-G. (2012). L-theanine partially counteracts caffeine-induced sleep disturbances in rats. Pharmacology, Biochemistry, and Behavior, 101(2), 217–221. https://doi.org/10.1016/j.pbb.2012.01.011
18) Borzelleca, J. F., Peters, D., & Hall, W. (2006). A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats. Food and Chemical Toxicology : An International Journal Published for the British Industrial Biological Research Association, 44(7), 1158–1166. https://doi.org/10.1016/j.fct.2006.03.014
19) Haskell CF , et al. “The Effects of L-theanine, Caffeine and Their Combination on Cognition and Mood. – PubMed – NCBI.” National Center for Biotechnology Information.
20) Foxe JJ , et al. “Assessing the Effects of Caffeine and Theanine on the Maintenance of Vigilance During a Sustained Attention Task. – PubMed – NCBI.” National Center for Biotechnology Information,
21) Kahathuduwa CN, Dassanayake TL, Amarakoon AMT, Weerasinghe VS. Acute effects of theanine, caffeine and theanine-caffeine combination on attention. Nutr Neurosci. 2017;20(6):369-377.
22) Rogers PJ, Smith JE, Heatherley SV, Pleydell-pearce CW. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology (Berl). 2008;195(4):569-77.
23) Einöther SJ, Martens VE, Rycroft JA, De bruin EA. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite. 2010;54(2):406-9