Have you been drinking your daily L-theanine?
It’s good for you after all – or at least, usually, that is. The cutting-edge of coffee brands and even nootropic supplement companies have likely dosed you with L-theanine more than once.
Whether to your knowledge or not, the gist is that L-theanine is ‘the latest’ fortification to come to caffeine drinks, energy drinks, even electrolyte water products – positioned akin to that of a daily vitamin.
Maybe rightfully so. But... the problem isn’t so much about the real benefits of L-theanine, there are a number which are well-documented.
Instead, the problem is that synthetic L-theanine (i.e. unnaturally isolated/produced) could be masking the negative effects of those drinks.
Introduction: Are L-theanine Extracts Safe?
Potentially worse, there may be direct risks of synthetic theanine isolates, a big difference between the natural origin of L-theanine (found in high levels from only one trusted place in nature – matcha green tea powder).
Something that those getting their daily L-theanine from matcha powder do not need to worry about is whether a given distributor is following good manufacturing practices, or accurately accounting for purity and potency.
Coffee with L-theanine – Is it Safe? Best L-theanine
We’ve covered all of the health benefits of L-theanine in its natural form before. But here are some cautions against the growing trend of adding L-theanine isolate to energy drinks and coffee.
Keep reading if you’ve drunk “L-theanine fortified coffee”, or even specifically created this concoction on your own accord. Here’s your fair warning:
Finding the best L-theanine Natural Complex
In theory, products ‘developed’ by nature have healthy levels of amino-acids, phytonutrients, antioxidants, and key vitamins and minerals. Just to name a few, it’s by ingesting whole-food products that our health is honored by a natural, unadulterated balance.
But what happens when you start extracting, or ‘mixing and matching’ isolated compounds from one source into another?
Reliable L-theanine: Entourage Effect
For one, there is a loss to the natural entourage effect. Where one compound can bring balance to another, that’s no longer the case.
In fact, it’s an established fact that extracts of all kinds tend to have side effects as a result of removing compounds from their natural counterparts.
Side-effects of L-theanine Extracts
One great example is with pharmaceuticals; these are often drugs originating from natural plant sources. Yet, when you isolate one compound by taking it out of nature, a more intense effect is created rather than being mild and generally safer when in whole-plant form .
Could this be the case for synthetic theanine? Yes, it looks like it could be...
Is L-theanine Addictive? Synthetic L-theanine Risks
There is no research to indicate that high doses of L-theanine found in supplements or fortified-coffee drinks are addictive. However, there is also no research that definitely proves without a doubt that synthetic forms of theanine are able to be safely metabolized by the body as compared to natural sources.
One of the reasons for this is that synthetic isolates of theanine may contain an unnatural ratio of the chiral types of theanine (D-theanine to L-theanine) than that found in healthy green tea powder .
To reiterate, there's great reasons to be interested in the health benefits of L-theanine. We cover all benefits in a recent article, but below we document research about what separates natural L-theanine from synthetic L-theanine.
Including some reasons that you should be wary of non-matcha L-theanine.
Theanine: Generally Regarded as Safe by the FDA
While L-theanine is considered generally safe by the FDA, the number of research publications are far outshined by the host of long-standing science done on behalf of L-theanine that is naturally occurring in green tea leaves.
Still, there’s two parts to the question of whether you should use a theanine supplement: safety and efficacy:
Efficacy of Theanine
Firstly, it’s unfair to assume that the benefits seen from theanine in green tea are able to carry over to energy drinks or fortified coffees, especially considering that some benefits are only known to be active when in conjunction with polyphenols (EGCG) in green tea , including smooth-muscle tone and relaxation.
Safety of Theanine
Second, and perhaps more importantly, the influx of this trend of adding L-theanine to coffee ultimately begs the question whether the FDA’s decision from years ago will stay true as new manufacturers cut corners to supply the growing market.
GMP Theanine – Should you Trust it?
Considering that one of the few tested sources of synthetic theanine is patented (Suntheanine®), including the production method, it’s questionable how other manufacturers will ensure quality with novel isolation techniques.
One of the most important concerns here is regarding the amino-acid D-theanine, the ‘other-handed’ structure of the L-theanine molecule (together making for the chiral types of theanine).
According to a recent meta-analysis, there is no research yet on the health effects, safety, or efficacy of D-theanine .
Safety of D-theanine
And furthermore, considering that biosynthesized theanine will unavoidably contain levels of this compound before further isolation, it’s more appealing than ever to simply stick to a time-tested source of theanine that doesn’t pose question or doubt.
Can you Overdose on L-theanine?
Next in the line of caution regarding added L-theanine to your coffee or water – many people are wondering whether it’s possible to overdose on L-theanine. The FDA’s opinion that generally regards it as safe is still relevant, but it’s no longer the full picture.
Where to Buy L-theanine
When L-theanine is consumed outside of its natural form it also means that it’s not being ingested alongside other key ‘balancing compounds.’ These include EGCG, caffeine, and other flavonoids.
From what should be a natural mixture found only in sources like Japanese matcha or certain medicinal mushrooms, now one must wonder what L-theanine will do inside their body.
L-theanine Half Life and whether to order L-theanine Powder
Even considering the half-life of L-theanine, it’s questionable whether synthetics will perform with similar potency and all-day energy. It’s also a question whether L-theanine powder has the same level of safety as natural sources.
In fact, in a recent review of clinical research, one study evaluated the effects of high doses of L-theanine (higher than you’d receive in natural sources) on alpha brain waves.
It found contradicting results where alpha waves were reduced, as compared to when heightened from natural L-theanine .
Relaxation Properties of L-theanine Supplements and L-theanine Extracts?
Considering that the synergy (and critically – the ratio) of caffeine and L-theanine is a well-documented relationship involved behind potential relaxation/cognitive benefits , that very research implies how unpredictable such an extract could be.
And, as earlier mentioned, the muscle relaxing properties of theanine involve a combined effect with compounds naturally alongside it (like not of fortified coffee).
Organic L-theanine Powder: Benefits and Original Source
It’s solely by similar logic that other potential benefits of L-theanine are inextricably tied to its original form (matcha powder), not limited to: heart-health benefits of theanine, cognitive & longevity benefits of theanine, antioxidant benefits of theanine, and the potential atherosclerosis therapeutic benefits of theanine .
Unintended Effects of L-theanine Synthetics
From the above, it’s indeed feasible that the unexpected outcome regarding alpha-brain waves could be due to faulty extracts which do not carefully control for the chiral nature (right and left-handed types) of the theanine amino-acid .
Specifically, it could be due to D-theanine that has a negative side effect on alpha waves, again, not something one would need to worry about with a natural daily source established as a suggestion to promote them .
More General Reasons to Avoid L-theanine Fortified Coffee Drinks
It’s also recommended to consider all of the unknowns with added L-theanine supplements to drinks, foods, and otherwise. For one, the savory flavor of L-theanine could be used in some energy drinks to further mask added sugar content.
Second, potency and actual dosages are not regulated and you could end up with more than anticipated – again, not a problem when enjoying it naturally through green tea.
L-theanine Dosage and Best Dosage for Brain Boost
Third, excess L-theanine fortification could similarly mask the dangerous effects of having too much caffeine, a known problem of many energy drinks, even coffees.
It’s known that excess caffeine may cause stress on a neurochemical level, as well as other issues like mid-day crash and metabolism.
Conclusion: Natural L-theanine and Caffeine Supplement
Finally, while L-theanine might be helpful to negate those problems, it’s simply an unknown territory. Fortunately though, there’s a natural product that already is excellent at balancing the energizing benefits of caffeine, with the calming and focusing qualities of L-theanine.
- Fun Tip: Matcha also has a much older history than coffee, which is only a fraction as old as matcha green tea.
The bottom line – Should you Stack L-theanine with Caffeine?
You don’t have to ask yourself whether to choose L-theanine or coffee, or L-theanine vs caffeine – why not get them both in a safe and enjoyable way?
It’s simple… choose matcha!
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 Mackenzie, R. (2011). The neuroethics of pleasure and addiction in public health strategies moving beyond harm reduction: Funding the creation of non-addictive drugs and taxonomies of pleasure. Neuroethics, 4(2), 103-117.
 Türközü, D., & Şanlier, N. (2017). L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety. Critical reviews in food science and nutrition, 57(8), 1681-1687.
 Unno, K., Furushima, D., Hamamoto, S., Iguchi, K., Yamada, H., Morita, A., ... & Nakamura, Y. (2018). Stress-reducing function of matcha green tea in animal experiments and clinical trials. Nutrients, 10(10), 1468.
 Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., & Scholey, A. B. (2008). The effects of L-theanine, caffeine and their combination on cognition and mood. Biological psychology, 77(2), 113-122.