In this article I will go in depth about what makes Guayusa different, looking at some interesting studies. For those who can’t be bothered with all the analysis and science, see my findings below, otherwise scroll down to the juicy details.

Guayusa benefits:

  • High Caffeine levels: Improved wakefulness, focus, and greater mental and physical performance.
  • Raises histamine; Improving cognitive performance and mood.
  • Better for regular drinking in regards to health, especially compared to coffee (more explanation later)
  • More heart healthy chlorogenic acids compared to roasted coffee and tea.
  • Particular to Guayusa tea: a calm, warm sense of energy – rather than the jittery, anxious energy of coffee.

Side effects:

  • It is high in caffeine and high doses of caffeine can be dangerous, so drink in moderation. Tolerance levels are different from person to person, but if you consume too much (300mg-400mg, that would be 4-6 cups of Guayusa brewed at full strength), you are likely to experience at least some of these side effects:
    • Headache
    • Insomnia
    • Anxiety
    • Irritability
    • Frequent urination or inability to control urination
    • Fast heartbeat
    • Muscle tremors
    • Nausea
    • Fatigue – after the caffeine levels have left your bloodstream you may feel more tired than normal. As if your body has to ‘catch up’. Best to consume moderate levels of caffeine for this reason.
  • It also raises histamine a little, a small amount is a good thing, but if your histamine levels get too high you may experience these side effects:
    • Itchy skin, eyes, ears, nose
    • Difficulty Sleeping
    • Hives, rashes, athletes foot
    • Tissue swelling, especially facial and throat
    • Hypo-tension (drop in blood pressure, dizzy when you stand up quickly)
    • Rapid heartbeat, heart palpitations
    • Anxiety or panic attack
    • Chest pain
    • Nasal congestion
    • Seasonal allergies
    • Conjunctivitis (red itchy and watery eyes)
    • Headaches and migraines
    • Fatigue, confusion, irritability
    • Digestive upset
    • Heartburn and re-flux
    • Blackouts and loss of consciousness
  • Generally speaking, with 2 or more cups of Guayusa, these are the side-effects you are more likely to experience:
    • More pooping (though you could consider it a cleanse)
    • More peeing
    • More thirsty than you would have been if you had just drunk water
  • And if you have it within 5 hours of going to sleep:
    • Difficulty Sleeping
    • Lighter less fulfilling sleep (maybe some lucid dreams)

The Quick Takeaway

Don’t let all those side effects scare you, as they say, too much of anything is bad thing.

If you regularly consume caffeine, or your lifestyle/job requires you to perform at you best, Guayusa is a good alternative for daily usage compared to coffee. As always, the caffeine will enhance mental and physical performance, although from my analysis, I conclude that consuming Guayusa regularly is safer and better for your cardiovascular health than consuming coffee regularly.

However if you find you have difficulty sleeping or experiencing any other side effects of high histamine levels, stop drinking Guayusa immediately. It is also important to have ways of winding down in the evening, since nothing is more performance enhancing that a good nights sleep.*1

Guayusa health benefits and side effects

For more comparisons between coffee and Guayusa see our other article.

Common Myths about Guayusa

  • It has a low tannin content. Misleading and almost definitely false. It has a tannin content equal to and if not more than ordinary tea.*2 That’s not necessarily a bad thing, it’s even a good thing, since all tannins are polyphenols, and polyphenols are anti-oxidants. The marketing claim that the “tannins in coffee stain your teeth but Guayusa does not” needs investigation. Tannins are also known for blocking iron absorption, but further research has shown that only non-heme iron is blocked.*3
  • The L-theanine content is significant and works synergistically with the caffeine. False. The l-theanine content is negligible.
  • The theobromine and theophylline content is significant. False. Again, both are of negligible amounts.

The Juicy Details

In the name of good research I will try and reference everything appropriately. When the reliability of a source of information is more dubious, this will be pointed out. We hope you learn something here that you could not have found anywhere else, and enjoy!


Starting with the basics. Guayusa is high in caffeine. One serving of 5g*4 brewed for 10 minutes will contain about 82mg*5 of caffeine. A cup of coffee contains on average94mg of caffeine*6. For comparison, tea has on average between 14 to 61mg of caffeine per serving*7

Important note: When comparing tea directly to Guayusa, it is important to note, that per dry weight the caffeine levels are similar*8, or Guayusa may even have less caffeine per gram than tea. However, since Guayusa is brewed stronger (and tea would be difficult to brew stronger since it will become too bitter from its tannin content), Guayusa ends up being more highly caffeinated. For the same reason, we will find that a Guayusa brew is also often more nutrient dense than most teas.

Theophylline and Theobromine

Another two psychostimulants present in Guayusa are called, theophylline and theobromine. Just like caffeine, these are both part of a group of compounds called ‘methyxanthenes’. They are found mostly in tea and cocoa.

Theobromine has been reported in Guayusa to be 0.08-0.25mg/g*9(0.008-0.025%), this is compared to 1.5-3% in cocoa beans, 0.02mg/g (0.02%) in green coffee beans, 0.15-0.2% in tea and 0.3% in dried mate. So it is rather negligible; more similar to coffee, and much lower than yerba mate and cocoa beans respectively. Theophylline content is even more negligible at levels of 0.002-0.005mg/g.


Guayusa also contains L-theanine. It has about 1.3mg/g of dried leaf compared to tea which contains about 20-50mg/g of dried leaf. Once again the L-theanine levels of Guayusa are too low to have any meaningful impact on the drinker.*10

Companies trying to market the benefits of Guayusa often talk about the high theobromine and theophylline levels, and the L-theanine levels, although from this research, I would conclude that it contains comparatively small amounts of all. Small enough to say that they are irrelevent in normal consumption.

Chlorogenic Acids

What may be more relevent is the chlorogenic acid content in Guayusa. It has similar levels to green coffee beans in fact.

26.5mg/g of chlorogenic acid per dry weight in guayusa compared and total phenolics of 106.62 for blanched guayusa compared to 54.87mg/g for unblanched guayusa. Very interesting find, from now on we will always recommend blanching guayusa, even if it may wash some of the caffeine out. Green coffee beans for comparison contain 35-75mg/g*11, so not too disimillar. Of course, note that roasting the coffee beans will destroy a lot of it. Green tea for comparison is measured as 0.366mg/g for dry leaves.*12Green yerba mate is 23.8mg/g and toasted yerba mate is measured as 3.16mg/g. Almost all yerba mate available to buy is smoked, which we guess is similar to toasting.


Guayusa contains 19 out of a total of 20 existing essential and non-essential amino-acids. Interesting fact, but I personally doubt that the quantities are significant when it comes to day to day consumption of the tea. Maybe it would be more important if you consume the whole leaf. This is something for us to research further.

The Most Interesting Study – What makes Guayusa special.

So far nothing is too shocking… and then there’s the study funded by Applied Food Sciences (AFS) and conducted by Miami Research Associates*13. Normally it is wise to be dubious when a study is funded by a company that has special commercial interest in the product. In this case, I have no reason to believe there was any foul play, although I would still like to see this replicated in another similar study.

The study itself is a double-blind crossover clinical trial comparing human consumption of 200mg of caffeine from AMATEA™ Guayusa extract to 200mg of caffeine from a green coffee extract. The results were nothing short of remarkable*14. Adrenalin levels in the subjects were 6-7x less for those that consumed the Guayusa extract. Meanwhile, norepinephrine, acetylcholine, serotonin and histamine levels were significantly higher. Evidently the bodies chemical response to guayusa compared to coffee is quite different, and this is what I will further investigate with you, to figure out exactly what is happening, how it effects to body, and hopefully figure out why it’s happening.

What happens to the guayusa drinker compared to the coffee drinker?

1. While Adrenalin (epinephrine) decreases 6-7x, Noradrenalin (norepinephrine) output is about doubled. Ephinephrine and norepinephrine have similar effects on the body on the whole though there are some subtle and important differences. Epinephrine has more an effect on the heart, while norepinephrine works on the blood vessels – mainly to increase and maintain blood pressure. “Norepinephrine is continuously released into circulation at low levels while epinephrine is only released during times of stress.”*15

2. Acetylcholine levels are doubled on average. Acetylcholine is a neurotransmitter commonly used as a supplement for those who want to improve memory and cognition.

3. Seratonin (the “happy hormone”) levels were 2-3x as high. Apart from regulating the mood, seratonin also aids cognitive function.

4. Histamine levels are almost tripled in a similar pattern to seratonin. You might remember histamines as that thing that you want to get rid of with ‘antihistamines’ when you’re suffering from hay-fever. But they’re not always the enemy, they are mainly known as an immune response to remove allergens from your body by making you sneeze, tear up or itch. Sometimes harmless things such as pollen or dust can trigger the histamine by accident, that’s when you may take an anti-histamine to alleviate the symptoms.

But histamine is much more than immune system support. It is a neurotransmitter, and is actually directly responsible for the increase in epinephrine, acetylcholine and seratonin. It regulates aggression and the sleep-wake cycle.

Raised histamine levels from guayusa is most likely from blocked Dao receptors in the same way mate, green tea and energy drinks do.*16

On one hand high performers tend to have high histamine levels, on the other hand, if the levels are too high there are numerous unwanted side effects*17. Decreased brain histamine causes neurobehavioural symptoms such as anxiety-like behaviors and impaired learning/memory. In contrast, increased brain histamine produces appetite suppression, anxiolytic actions and improves cognitive function.*18

If your histamine levels are too high however, you may have difficulty sleeping, and a bunch of other ugly side effects. So you want high histamine levels, but not too high, and only when you need to perform – definitely not when you need to wind down, sleep or relax.

Recommended use case for Guayusa compared to Coffee

So, to reiterate the difference between coffee and Guayusa. Coffee elicits a much greater flight or flight (adrenal) response, while Guayusa stimulates the expression of histamine, which is more about up-regulating the mind and body when it is performing at a high level. The way I would interpret this to apply it for our own use, Guayusa is good for maintaining high levels of performance throughout the day, while coffee is good for acute periods of performance, for example sprints. This is all the more true because the caffeine from coffee peaks and falls a lot faster than that from Guayusa, something I’ll talk about under the next heading.

It is also important to consider the effect of high adrenal levels from coffee. “Persistent epinephrine surges can damage blood vessels and arteries, increasing blood pressure and raising risk of heart attacks and strokes”*19Most people are familiar with the fact that chronic stress is bad for you body long term. So it seems wise to use coffee sparingly compared to Guayusa for the sake of long term health.

The rates of release of caffeine

The caffeine consumed from guayusa absorbs a lot slower into the bloodstream compared to that of roasted coffee. The main reason for this is that the high level of polyphenols in Guayusa slow down the digestion of the caffeine, while roasted coffee has very little polyphenols because they are damaged in the roasting process (unlike coffee made from green coffee beans which would have a very similar rate of caffeine release).

Because of this the caffeine from Guayusa may taper over a period of 4-5 hours in contrast to coffee lasting 2-3 hours.

What have we learnt?

Unlike I previously thought, the reason Guayusa drinkers don’t get the coffee jitters is nothing to do with the L-theanine, but everything to do with the histamine vs adrenaline response.

There are many other foods that raise histamine levels, so I might be left wondering, “what is so great about Guayusa?”. Except I’m not, because there’s one fact that cannot be escaped. Guayusa also has caffeine. The only question is, do you want caffeine with histamine, or do you want caffeine with adrenaline. The choice is yours.

What we still don’t know?

We don’t know why the adrenal response of Guayusa is a lot lower than coffee. I have a suspicion it’s something to do with the raised histamine levels, though I cannot find any study proving a direct correlation.


1* Ted talk – Sleep is your superpower -Matt Walker.

2* Other websites have made claims that the tannin content in Guayusa is low, but have provided no evidence. They are wrong. I think RUNA was the first to make the claim, and being taken as an authority on Guayusa many have taken it as fact. We ourselves have been guilty of it talking about the low tannin content of Guayusa. It could be about the mix-up around tannins and pseudo-tannins. For most intents and purposes pseudo tannins and tannins are all simply classified as tannins. They are similar in almost all ways except molecular weight. Pseudo tannins are smaller molecules than tannins. The only difference I can find is that tannins (not pseudo tannins) can be used for tanning leathers (staining a darker colour). Whether this also extends to teeth, where tannins stain teeth but pseudo tannins do not, I don’t know. Although it sounds plausible. If anyone (who has a knack for science) can figure this out for me this read might help. For investigation: Do pseudo tannins stain teeth? How much tannins vs pseudo tannins does guayusa have compared to coffee, black tea and green tea? Therefore, can we claim guayusa stains teeth less than coffee, black tea or/and green tea?

This study shows that the gallic acid content in guayusa is around 116mg/g. Why does that matter? Because there are actually 3 major groups of tannins. Two of those are from gallic acid and chlorogenic acid, the other is from catechins (which included EGCGs). Guayusa is high in catechins, chlorogenic acids and gallic acid, and therefore in not low in tannins.

3* Tannins reduce iron absorption although only non-heme iron.

4* The serving size is calculated from the traditional serving of 5 leaves per cup as drunk by the Kichwa tribe of Ecuador see this link for reference. We then aquired some leaves and found that on average they weigh 1g, and so came up with the number – 5g per cup.

5* On average, although the caffeine content can vary significantly from season to season and from farm to farm. Because Guayusa is grown in the rainforest, not in a controlled envirornment, these variations are inevitable. The caffeine in a cup hot brewed from 5g of Guayusa can range from anything between 60mg and 100mg. (in the future we intend to have every batch tested so we can give you a precise figure every time).

6* Coffee, brewed from grounds as reported by the Agricultural Research Service of the United States Department of Agriculture.

7* This number was derived from a range of teas; white, green and black. The results showed there was no observable trend in caffeine concentration due to variety of tea. Link here.

8* This study showed caffeine levels in green tea around 36.6mg/g (3.66%) per dry weight (which is the highest level we could find for any tea) Compared to 19.08mg/g (1.9%) of caffeine in Guayusa from this study. Looking at the lab-test results supplied from our own supplier, we have seen caffeine levels ranging between 1.9% and 2.4%, with an average of 2.1% from 7 different batches.

9* In this 2019 study.

10* Found in this interesting study. Section 2.2 and 3.3.1.

11* 3.5%-7.5% translates to 35-75mg/g, green coffee bean study

12* Comparison of cholorogenic acids in teas.

13* This study, although funded by AFS has this disclosure: “This research was sponsored by Applied Food Sciences Inc., the manufacturer of the JAVA.g and AMATEA extracts. Applied Food Sciences Inc. was involved in the research design, protocol formation, and review of the final manuscript, but QPS MRA (Miami Research Associates) was exclusively responsible for the execution of the clinical trial, analysis of the data and the interpretation of the results.”

14* See this summary of the study.

15* Article from


17* Article about histamine, side effects are also listed in this article under the heading “what are the symptoms of histamine intolerance?”

18* Study investigating how histamine works in the body.

19* This article from Harvard Health Publishing.