Theanine

Negative side effects of Theanine

When given to children in 400mg doses daily for 6 weeks, it resulted in no negative side effects. These 400mg doses were divided into two, one with breakfast and one in the afternoon. [16]

All other studies that we have reviewed examined the effects of smaller doses for a shorter period in older people (who might be expected to be more tolerant of the drug). None of these studies mentioned any negative side effects, but they mostly examined its safety when used in single doses.

How much and how often should you dose Theanine?

Theanine is generally consumed as-needed or daily in 100-200mg doses. This is also the dose-range that has been studied and found beneficial for the enhancement of certain aspects of cognitive functioning and mood.

Smaller or larger doses may do nothing or even impair cognitive performance. [25]

What time of day should you take Theanine?

Some studies suggest it is effective for improving sleep, but it wasn't used prior to sleep in these studies. Many of the studies that found cognitive benefits from 100-200mg of Theanine examined its effects throughout the day of use. This suggests that to get the most benefits from Theanine, you should use it during the day, for example in the morning.

What form of Theanine is the most effective for stress reduction and cognitive enhancement?

L-Theanine is much more effective and science-backed for cognitive enhancement than D-Theanine.

Unless otherwise stated, all mentions of Theanine on this page regard L-Theanine.

What are the effects of combining Caffeine and L-Theanine?

The classic caffeine and L-Theanine stack which many people have reported that they get good focus with no nervousness from usually contains 100mg caffeine and 200mg l-theanine. If you've never combined two nootropics into a stack before, this is a good beginner stack for you, considering it comes with a high probability of positive effects with low risk for negative side effects.

In fact, you have likely consumed this nootropic stack without knowing. Green tea contains both L-Theanine, and Caffeine

”What’s really interesting about how we normally ingest caffeine is that it’s ingested with vasodilators. So if you look at caffeine in tea, tea contains catechins which we know increase blood flow. If you look at caffeine in coffee, coffee contains these things called chlorogenic acids which again increase blood flow. [...] Humans tend to ingest caffeine in a form which not only have you get caffeine in there but also there are these substances which oppose the reduction in blood flow.” ~ Nootropics researcher Andrew Scholey on the Nootralize podcast.

One study found that 75mg Caffeine and 50mg Theanine resulted in no beneficial cognitive or behavioral effects for healthy humans. [5] Caffeine did have benefits when given alone in this study. This likely means that the doses used were too small, and that the potential synergistic effects that the combination could result in in higher doses isn't present in smaller doses.

In another study participants received 250mg Theanine and 150mg Caffeine. [33] On top of exerting the same benefits as 150mg Caffeine alone, the combination improved reaction time on several cognitive tests, and improved sentence verification accuracy. The "stack"also reduced subjective tiredness and increased subjective alertness, more than Caffeine alone.

One study, conducted in healthy humans, suggests that some of the acute cognitive benefits of the combination of Caffeine and Theanine are thanks to reduced mind-wandering and decreased tendency to lose concentration to distracting stimuli. [35]

How does Theanine work?

The mechanisms of action of Theanine have not yet been fully discovered by researchers.

Scientists have found that Theanine can exert the following neurobiological effects:

• Increased brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate, and NMDA receptors (in animal studies) [37]
• Decreased background alpha band activity levels and increased attention-related anticipatory alpha band activity levels (in humans performing a task demanding attention) [38]
• Enhanced alpha electric band generation in occipital and parietal region of brain and increased synthesis of γ-aminobutyric acid (GABA) (study type undefined)[1]
• Increased long-term potentiation (LTP) in the dentate gyrus (in rats) [40]
• Increased brain-derived neurotropic factor (BDNF) and nerve growth factor (NGF) in the hippocampus (in rats) [41]
• Eliminated the vasoconstrictive effect of Caffeine (in humans) [32]

Is Theanine neuroprotective?

The short answer is that yes, Theanine has been found to exert neuroprotective effects in several animal studies. [43]

However, the contexts in which the compound might protect the brain in humans are underresearched and it is therewith unknown whether it can have such beneficial effects on brain health.

How much Theanine is in different forms of tea?

In general, the amount of Theanine in any specific sort of tea varies between samples of that specific tea sort. [44] This means it is impossible to say exactly how much Theanine is in for example a cup of Green Tea.

If you want a quick but imprecise answer, here it is:

"Contrary to previous research, a standard (200 ml) cup of black tea was found to contain the most l-theanine (24.2 ± 5.7 mg) while a cup of green tea contained the least (7.9 ± 3.8 mg)." [46]

For a more precise answer let's look at the results of another study. Many samples of different forms of teas were taken and the contents of Caffeine and Theanine in them were analyzed. These were the results (in mg/g):

_{Src: Pharmacognosy Magazine. Boros, Csupor, and Jedlinszki. Image included for educational purposes from "Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples".}

To conclude, it's best to use a Theanine supplement, such as the one sold by Mind Nutrition, so that you can know exactly how much Theanine you're taking.