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Caffeine + L-Theanine

L-Theanine and Caffeine are powerful energizing compounds found in mushrooms/tea and in coffee, respectively. The benefits of using Caffeine with L-Theanine include significant mood boost, enhanced memory and cognitive performance, energizing effects, and improved metabolism.


Background of Caffeine + L-Theanine

Important Information, Benefits, Effects, and Important Facts

L-Theanine and Caffeine are two highly effective compounds with a long history of use in different cultures around the world. On the one hand, L-Theanine is typically used for its relaxing, calming, and stress-reducing effects, along with its powerful antioxidant benefits. On the other hand, Caffeine is used for its energizing, mood-boosting, and stimulating effects. Combining the two supplements has great benefits, all of which have been verified in studies from around the world.


Caffeine + L-Theanine capsules are typically used to improve mood, boost cognitive performance, and to stimulate mental energy. L-Theanine may also help mitigate some of Caffeine’s potentially negative side effects. The recommended serving size is 1-2 capsules of 250 mg once to twice daily. Side effects of too much Caffeine include nervousness, headache, tremor, spasms, palpitations, high blood pressure, insomnia, and indigestion. Do not exceed the recommended serving size.


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Caffeine + L-Theanine Reviews



Goods stuff, very good quality and price is as expected. Pills are high quality, bottle came with cotton and was packed to the brim with the pills =)



At a Quick Glance


Ingredients (1 capsule)

Caffeine - 100 mg
L-Theanine - 150 mg


How it Works

Binds to Adenosine Receptors
Releases Catecholamines
Active at GABA sites

Is Used For

Enhancing Cognitive Function
Mental Focus
Boosting Energy Levels
Improving Mood

Medical Disclaimer

Not intended to treat, diagnose, or cure any disease or ailment. Please read and fully understand potential adverse effects before using this product. These statements have not been reviewed by the FDA and are not written by a medical professional. Please consult your doctor before using any supplements, especially if you have any medical conditions.





Benefits and Effects on Humans

Based on Available Scientific Research and Anecdotal Evidence



Used For: Efficacy
Cognitive Enhancement ★★★★★
Boosting Energy Levels ★★★★★
Improving Mood ★★★★
Enhancing Mental Focus ★★★★★
Pre-workout ★★★




How to Use

Recommended Serving Size and Application


The serving size of our Caffeine + L-Theanine capsules is 250 mg, each containing 150 mg of L-Theanine and 100 mg of Caffeine. The recommended serving size is 1-2 capsules, once to twice daily. Always start with a lower serving (1 capsule) to assess your response to the supplement.


Since this product contains Caffeine, it is not recommended to use it after midday since it may interfere with your sleeping patterns. Best taken in the morning or 30 minutes prior to exercise. Do not exceed the recommended serving size.



Evidence-Based Research



1. Summary


L-Theanine is a fairly rare phytochemical and a non-dietary amino acid found primarily in a small number of mushrooms and in common tea, Camellia sinensis. For thousands of years, people in the East have used strong tea as a health-promoting and calming drink. Without knowing it, they were tapping into the benefits of L-Theanine. These include the ability to help reduce stress, improve mood and mental focus, boost your sleep quality, and promote a healthy circulatory system through its powerful anti-oxidant effects. [1]

Caffeine is even better known than L-Theanine. With coffee being the world’s most consumed drink, most people have a good understanding of Caffeine’s effects. It is energizing and stimulating, with noticeable improvements in mood and cognitive performance. The Caffeine compound is known as a purine alkaloid and is found predominantly in Coffea Arabica (the ‘coffee tree’), which is a dark green shrub that is indigenous to Ethiopia.[2]

Caffeine is a stimulant with potentially dangerous properties at high doses. It acts as a vasoconstrictor, meaning it increases blood pressure while improving focus and energy. A cup of coffee generally contains around 60mg of pure caffeine. More than 6 cups of coffee can be dangerous, and pure caffeine needs to be used very carefully to avoid potentially negative side effects. [3]


caffeine + l-theanine for focus


2. Human Effects and Benefits


The overall benefits and effects of Caffeine + L-Theanine capsules can be summarized into three categories, namely, the benefits of L-Theanine alone, Caffeine alone, and the benefits of combining the two.


2.1. Benefits of L-Theanine


2.1.1. Powerful Antioxidant Effects:

Studies have shown that L-Theanine has protective effects on the liver due to its ability to act as a powerful antioxidant. Alcohol consumption increases the amount of toxic chemicals called ‘free-radicals’ in your body. These cause harm to your liver and other organs. In 2012, scientists showed that L-Theanine has a significant protective effect on the liver by helping your body to destroy free-radicals. [4]


2.1.2. May Help Boost Mental State:

Studies have shown that the consumption of L-Theanine significantly increases the activity in alpha-frequency brainwaves in humans. Alpha brainwaves are associated with a relaxed, but alert state of mind. These effects are especially noticeable in concentrations that are higher than what you’d find in a cup of tea, for example. Alpha brainwave activity is thought to play an important role in attention and mental focus. [5]


2.1.3. Helps to Reduce Feelings of Stress:

Human studies have shown that supplementing with L-Theanine can reduce your response to stress. In one study, volunteers took an L-Theanine supplement and were presented with a stressful stimulus. The results showed lower heart rate and salivary immunoglobulin (s-IgA) for those who used L-Theanine. These are critical aspects of the stress response. [6]


2.2. Benefits of Caffeine


2.2.1. Energizing and Stimulating

Caffeine has powerful effects on the central nervous system (CNS). Through these effects, it is able to generate positive and noticeable effects on mental activity. It is particularly effective in activating noradrenaline receptors and affecting the release of dopamine. Essentially, caffeine increases mental and physical energy while improving mental stimulation and alertness. [7]


2.2.2. Improves Mood

People have known for a long time that caffeine can be used to improve mood. A single cup of coffee produces, for many people, noticeable effects on their state of mind and feelings of well-being. Numerous studies have been conducted to evaluate the mechanisms and the scientific soundness of these claims. Needless to say, there is now empirical evidence that Caffeine significantly helps to boost mood. [8]


2.2.3. Boosts Physical Energy and May Help Maintain a Healthy Metabolism

In a recent study, the effects of caffeine on energy levels and thermogenesis (production of heat in the body, as a result of increased metabolism) were studied. In the study, twelve healthy participants were given either Green Tea Extract, Tyrosine, or Caffeine (50 mg). Of the three substances used, only Caffeine produced a significant increase in thermogenesis. This means that Caffeine can be used to boost metabolism and physical energy/endurance. Furthermore, this evidence suggests that people may consider using Caffeine in addition to a healthy diet as a means of promoting weight-loss. [9]


2.3. Benefits of Using L-Theanine with Caffeine

When you take a supplement containing both Caffeine and L-Theanine, you’ll be getting the benefits of both these great compounds. This means you’ll feel noticeable improvements in mood, memory, and stress-reduction, while also feeling mentally stimulated and energized. This is definitely one of the top supplement stacks available today!


2.3.1. Helps Mitigate Potential Negative Effects of Caffeine

Studies into the effects of using L-Theanine with Caffeine show a highly synergistic relationship between the two. In one study, researchers found that L-Theanine helped to reduce the vasoconstrictive effects of Caffeine. In effect, this means that L-Theanine may help to reduce some of the potentially dangerous effects of Caffeine, especially for people with high blood pressure. [10]


2.3.2. Boosts Cognitive Performance

A number of studies have researched the synergistic effects of L-Theanine and Caffeine in combination, especially for your mental state. In one such study, researchers found that taking Caffeine with L-Theanine significantly improved cognitive performance and mood, while reducing the effects on heart-rate and blood pressure that are noticeable when using caffeine alone. [11]

In a similar study, researchers found that taking L-Theanine with Caffeine helped to reduce the adverse effects of both. This means fewer people reported headaches (which was common with high doses of L-Theanine). Furthermore, the combination improved Rapid Visual Information Processing (RVIP) accuracy scores better than either supplement alone, and also reduced ‘mental fatigue’ ratings. The results suggest a significant improvement in cognitive performance when using a combination of L-Theanine and Caffeine. [12]

caffeine for energy and focus  


3. Safety & Toxicity


3.1. Side Effects

Large servings of Caffeine can cause nervousness, headache, tremor, spasms, palpitations, high blood pressure, insomnia, and indigestion.[13] Large servings of L-Theanine can cause dizziness, upset stomach, and headaches.


Caffeine may not be suitable for people with a number of varying ailments. This includes people with anxiety disorders, bipolar disorder, bleeding disorders, heart conditions, diabetes, epilepsy, diarrhoea, glaucoma, high blood pressure, irritable bowel syndrome, or osteoporosis. If you have any medical issues, please consult your doctor before using a Caffeine supplement. [14]

Caffeine is also known to be addictive and withdrawal symptoms from prolonged caffeine use are common. Withdrawal effects may include headaches, irritability, anxiety, dry mouth, and nausea.[15] To avoid withdrawal symptoms, do not use high doses of Caffeine capsules for prolonged periods of time.


3.2. Overdose

Please be aware, it is possible to overdose on Caffeine. At extremely large servings, fatal overdose is possible. An overdose on coffee is very unlikely. However, using pure anhydrous Caffeine increases the risk because it is much easier to take a far greater amount. In one case study, a 39-year-old man passed away after consuming 12 grams of pure caffeine anhydrous.[16]


According to Healthline, overdose symptoms can occur at servings greater than 400 mg per day. This means that it is important to limit the serving of Caffeine + L-Theanine capsules to no more than 4 capsules per day, for healthy adults. Pregnant women are warned to reduce this to no greater than 200 mg per day.13



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How We Research Our Content

Our content is written using meticulous research methods and claims are backed by links to scientific references, wherever possible. The author and editors of Liftmode's Research Team have strong academic backgrounds in microbiology, physiology, and biochemistry.

Content Updated On: December 5th, 2018


Scientific Support and References


[1] Juneja, L. (1999). L-theanine—a unique amino acid of green tea and its relaxation effect in humans. Trends in Food Science & Technology, 10(6-7), 199–204.

[2] Barone, J. J., Roberts, H. R. (1996). Caffeine consumption. Food and Chemical Toxicology, 34(1), 119–129.

[3] Svatikova A., et al. (2015). Potentiated blood pressure responses to energy drink intake in caffeine naïve healthy adults: A double-blind randomized controlled study. Journal of the American College of Cardiology, 65: A1432.

[4] Li, G., et al., l-Theanine prevents alcoholic liver injury through enhancing the antioxidant capability of hepatocytes. Food Chem Toxicol. 2012 Feb;50(2):363-72.

[5] Nobre, A.C., Rao, A., Owen, G.N., L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. 2008;17 Suppl 1:167-8.

[6] Kimura, K., Ozeki, M., Juneja, L.R., Ohira, H., L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007 Jan;74(1):39-45. Epub 2006 Aug 22.

[7] Glade, M.J., Caffeine-Not just a stimulant. Nutrition. 2010 Oct;26(10):932-8

[8] Smith, A., Sutherland, D., Christopher, G. Effects of repeated doses of caffeine on mood and performance of alert and fatigued volunteers. J Psychopharmacol. 2005 Nov;19(6):620-6.

[9] Belza, A., Toubro, S., Astrup, A., The effect of caffeine, green tea and tyrosine on thermogenesis and energy intake. European Journal of Clinical Nutrition (2009) 63, 57–64 (2009)

[10] Dodd, F.L., et al., 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 Jul;232(14):2563-76.

[11] Giesbrecht, T., et al., The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci. 2010 Dec;13(6):283-90

[12] Haskell, C.F., et al., The effects of L-theanine, caffeine and their combination on cognition and mood. Biol Psychol. 2008 Feb;77(2):113-22. Epub 2007 Sep 26.

[13] Kerrigan, S., Lindsey, T. (2005). Fatal caffeine overdose: Two case reports. Forensic Science International, 153(1), 67–69. 

[14] Temple, J.L., Bernard, C., Lipshultz, S.E., Czachor, J.D., Westphal, J.A., & Mestre, M.A. (2017). The Safety of Ingested Caffeine: A Comprehensive Review. Frontiers in Psychiatry, 8.

[15] Juliano, L. M., & Griffiths, R. R. (2004). A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology, 176(1), 1–29.

[16] Jabbar, S.B., Hanly, M.G. (2013). Fatal caffeine overdose: a case report and review of literature. Am J Forensic Med Pathol, 34(4):321-4.