Have you ever sipped on a cup of tea only to feel your body take a deep breath and melt into your chair? Or maybe you’re feeling extra stressed, and a cup of green tea helps to take the edge off.
There’s something comforting about a hot beverage when you’re running on high, but it might not be the warmth calming you down—it might be L-theanine.
L-theanine is an amino acid known for its calming qualities, but it delivers several other health benefits—and that’s what we’re talking about now. This article covers everything you need to know about L-theanine and where the best place to find it is.
Best L-Theanine Supplement: Performance Lab® Caffeine 2™
Are you sick and tired of caffeine overstimulation? Are you done with the post-workout crashes after downing a stim-heavy pre-workout?
Caffeine can help boost energy levels and focus, but when used in high doses long-term, it can lead to unwelcome side effects and performance decrements—but it’s time that stops.
If you’re looking for laser focus, more attention, and better energy without side effects, Caffeine 2™ needs to be in your stack. It’s an ultramodern energy supplement designed with peak stim benefits in mind—with fewer side effects.
Caffeine 2™ combines NutriGenesis® Caffeine Balance B-Complex with natural caffeine, L-theanine, and L-tyrosine for cleaner, healthier, more relaxed energy, plus faster bounceback and less burnout.
When it comes to athletic performance, you want the best supplements for the best performance—and Caffeine 2™ ticks all the boxes.
Key benefits:
- Caffeine enhanced for superior nootropic, athletic and thermogenic performance
- Increases alpha brainwaves to balance caffeine energy with relaxation, creativity, and clarity
- Promotes alert, revitalized performance during multitasking, stress, and fatigue
- Reduces jitters, crashes, and other adverse effects associated with caffeine overstimulation
- Safe for daily use: Replenishes caffeine-depleted brain chemicals to prevent burnout
- Promotes balanced physiological responses to caffeine-induced stress
- Patented, cutting-edge nutrients from Suntheanine®, Ajipure®, and NutriGenesis®
Key features:
- NutriGenesis® Caffeine Balance B-Complex
- 500 mcg Riboflavin+ (Vitamin B2)
- 750 mcg Vitamin B6+
- 167 mcg Folate (Vitamin B9)
- 2 mcg Vitamin B12+
- 50 mg Natural Caffeine (from Coffea robusta seeds)
- 100 mg Suntheanine® L-Theanine
- 250 mg Ajipure® L-Tyrosine
What Is L-theanine?
If you’re a fan of green tea, you might’ve heard about L-theanine before. It’s a non-essential amino acid isolated from black and green tea leaves.
While there is some speculation that L-theanine may support weight loss—one of the primary benefits of consuming green tea—it's best feature is blocking glutamic acid from binding to its receptors in the brain, which curbs over-excitation for a calmer, more relaxed energy boost. This mechanism is one of the main reasons why sipping a cup of tea is relaxing and why it’s an effective supplement during periods of high stress or heavy mental exertion 1.But the other reason why people gravitate towards L-theanine, especially athletes, is its synergistic effects with caffeine. Caffeine is a stimulant known to increase energy and focus, but it can easily cause overstimulation and subsequent adverse effects like jitters, anxiety, rapid heartbeat, and more.
But when you combine L-theanine with caffeine, it mitigates some of the typical adverse reactions—reducing its stimulatory effects while lowering stress, improving alertness and accuracy, and generally enhancing physical and mental performance 2, 3.But now, you’re probably wondering exactly how L-theanine delivers these powerful effects—here’s how it works.To the body, L-theanine and the excitatory neurotransmitter glutamate look pretty similar. That means L-theanine can weakly bind to the same receptors, preventing glutamate from binding. Less available binds dampen glutamate hyperactivity, freeing it up to support GABA and a calm, feel-good alertness.On top of that, it also promotes neuroinhibitory and parasympathetic responses, which makes it a super helpful supplement when you’re experiencing higher than normal levels of neurotransmitters like norepinephrine and epinephrine, and in need of a boost in serotonin and dopamine.
When you combine the actions of L-theanine, you’re getting:
- Better focus and attention
- Reduced stress and anxiety
- Enhances sleep quality
- Better and more stable mood
- Increased motivation
- Sharper memory
But where caffeine is concerned, that’s where L-theanine shines. L-theanine can reduce the physiological responses to excessive caffeine intake and stress by inhibiting excitatory responses in the brain.
When you stack L-theanine and caffeine, they work synergistically to increase energy levels, attention, and focus, without causing overstimulation 4.
Simply put, L-theanine works on a few pathways to alter behaviors in the brain:
- Boosts levels of GABA and other calming brain chemicals that control emotions, concentration, mood, arousal, sleep, appetite, and more
- Lowers levels of “excitatory” brain chemicals and increases concentrations of chemicals that promote calmness
- Enhances alpha brain waves to promote “wakeful relaxation” and enhances relaxation, focus, and creativity
So, what’s it suitable for? A lot!
L-Theanine Uses And Benefits
L-theanine may be known for promoting a calm and relaxed state, but that’s not all it can do.
Whether you're sipping a cup of green tea or popping back pure capsules, here are the top uses and benefits of this amino acid:
Improves sleep
Because of its ability to block excitatory neurotransmitters and induce relaxation, L-theanine can be a great sleep support supplement.
Studies have shown that it can help people fall asleep faster (reduce sleep onset latency) and improve sleep quality. However, L-theanine doesn’t inherently have sedative properties; instead, it induces sleep through its anxiolysis (reducing anxiety) 5.
Reduces stress and anxiety
L-theanine might take the crown if there’s a solid supplement for generalized anxiety disorder (GAD).
It’s one of the most effective and non-drowsy compounds for reducing stress and mitigating anxiety symptoms by promoting relaxation and attentive wakefulness.
Research finds that just four weeks of L-theanine supplementation can decrease stress-related symptoms (depression, anxiety, sleep disruptions) and improve markers of cognitive function (verbal fluency, executive function) 6.
These anti-anxiety effects are due to increased alpha brainwave activity and increased synthesis of GABA, which, in turn, increases brain levels of dopamine and serotonin to improve feelings of calm and well-being 7, 8. As a result, it can help to alleviate many of the signs of physical and psychological stress.
Enhances cognitive function
Cognitive function is more than just how smart you are—it’s about your memory, attention, focus, learning abilities, and more.
While there is a class of supplements explicitly designed for cognition—they’re called nootropics—L-theanine is generally part of them but can be equally as effective on its own.
It may protect the brain against oxidative stress-induced neuronal damage and inhibit neurological functions that reduce antioxidant capacity and promote oxidative damage 9.
Other research suggests that caffeine and L-theanine can improve performance on cognitively demanding tasks 3.
May support weight loss
Don’t get your hopes up for L-theanine being your next fat burner.
However, some research suggests that taking L-theanine could help manage weight indirectly by regulating appetite, improving energy metabolism, and increasing fat loss via its sleep-supportive activity.
Boosts immunity
Vitamin C might have been your go-to for immune support, but what about L-theanine?
Research suggests it could be one to add to your immunity stack. L-theanine regulates immune cytokine secretion, and drinking theanine-rich tea can induce an innate immune response and immunologic memory 10.
How Much L-theanine?
While there’s no “ideal” dose to reap maximal benefit from L-theanine, most studies and clinical trials administer between 100 and 250 mg for optimal results.
That said, some evidence suggests the anti-anxiety effects of L-theanine are most pronounced with doses between 200 to 400 mg daily 11. For better sleep quality, doses between 250 mg and 400 mg have also been effective 12.
Although most studies use doses below 500 mg per day, L-theanine hasn’t shown toxicity, even at doses up to 6,000 mg per day.
Whether you’re looking for better sleep, calm clarity, or to reduce anxiety, taking L-theanine is a smart idea.
And each capsule of Caffeine 2™contains 100 mg of Suntheanine® L-theanine—the purest and most potent form of L-theanine—and it’s safe to take up to five capsules daily for maximum benefit!
References
- Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007;74(1):39-45.
- Giles GE, Mahoney CR, Brunyé TT, Taylor HA, Kanarek RB. Caffeine and theanine exert opposite effects on attention under emotional arousal. Can J Physiol Pharmacol. 2017;95(1):93-100.
- Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. 2008;11(4):193-198.
- 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.
- Rao TP, Ozeki M, Juneja LR. In Search of a Safe Natural Sleep Aid. J Am Coll Nutr. 2015;34(5):436-447.
- Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362.
- Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. 2008;17 Suppl 1:167-168.
- Nathan PJ, Lu K, Gray M, Oliver C. The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent. J Herb Pharmacother. 2006;6(2):21-30.
- Takeshima M, Miyazaki I, Murakami S, Kita T, Asanuma M. l-Theanine protects against excess dopamine-induced neurotoxicity in the presence of astrocytes. J Clin Biochem Nutr. 2016;59(2):93-99.
- Juszkiewicz A, Glapa A, Basta P, et al. The effect of L-theanine supplementation on the immune system of athletes exposed to strenuous physical exercise. J Int Soc Sports Nutr. 2019;16(1):7.
- Everett JM, Gunathilake D, Dufficy L, Roach PD, Thomas J, Upton D, Naumovski N. Theanine consumption, stress and anxiety in human clinical trials: A systematic review. In 39th Annual Scientific Meeting of the Nutrition Society of Australia 2015. 2015.
- Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011;16(4):348-354.
