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Guayusa Tea

How guayusa, the caffeinated Amazonian holly leaf, delivers smooth energy alongside antioxidants comparable to green tea and emerging evidence for mood and blood sugar support

Guayusa (Ilex guayusa) is a caffeinated holly tree native to the upper Amazon basin of Ecuador, where the Kichwa people have brewed its leaves as a morning tea for centuries. It sits somewhere between green tea and yerba mate in flavor — earthy and smooth, without the bitter edge of either.

What makes guayusa distinctive is its combination of caffeine and theobromine (the compound also found in dark chocolate), which many people find produces a calm, alert energy without the jitteriness that coffee can cause [3]. It also carries a notable antioxidant load, with chlorogenic acids and flavonoids comparable in some measures to Camellia sinensis green tea [2].

A 2024 randomized double-blind crossover trial found that a moderate dose of guayusa extract significantly improved mood, reduced fatigue, and enhanced motor-cognitive speed compared to placebo in healthy adults [4] — the first well-controlled human evidence for its cognitive effects.

What Is in Guayusa

Guayusa leaves contain three main categories of bioactive compounds [1][3]:

Methylxanthines: Caffeine is the most abundant stimulant, typically 1.5–3.0% of dry leaf weight, comparable to many green teas. Guayusa also contains theobromine (the mild stimulant in chocolate) and small amounts of theophylline. The combination of caffeine with theobromine tends to produce a more gradual energy onset and longer duration than caffeine alone, which is one reason guayusa is often described as producing less jitteriness than coffee [3].

Chlorogenic acids: The dominant antioxidants are mono- and dicaffeoylquinic acid derivatives — the same family of phenolics that makes coffee and yerba mate antioxidant-rich. These compounds have been studied for their effects on blood sugar regulation, lipid metabolism, and inflammation [3].

Flavonoids and carotenoids: Chlorogenic acid and quercetin-3-O-hexose are the chief flavonols, while lutein is the most concentrated carotenoid [1]. Luteolin and kaempferol derivatives add further antioxidant depth.

How It Compares to Green Tea

In the most direct head-to-head study, guayusa tea preparations provided 60–80% protection from oxidative stress in cellular antioxidant assays — broadly comparable to Camellia sinensis teas tested at similar concentrations [2]. Anti-inflammatory activity (measured as inhibition of nitric oxide production in stimulated immune cells) was also similar between guayusa and green or black tea.

Where guayusa differs is in its specific compound profile. It lacks the catechins (EGCG, EGC, ECG) that make green tea distinctive, relying instead on caffeoylquinic acids for antioxidant potency [2]. This matters because different phenolic classes act on different pathways. Guayusa is not a replacement for green tea but an alternative with overlapping and some distinct benefits.

Cognitive and Mood Effects

The caffeine-theobromine combination accounts for part of guayusa's effect on alertness, but the 2024 human trial by Helwig et al. went further [4]. In 25 adults given either 600 mg or 1,200 mg of a standardized guayusa extract, or placebo, the lower dose produced:

Significantly lower total mood disturbance score
Reduced fatigue-inertia ratings
Improved perceived energy and focus
Faster motor speed and psychomotor speed

The higher dose additionally reduced reaction time in a neurocognitive test. Crucially, no significant cardiovascular effects (elevated blood pressure, heart rate, or QT interval changes) were observed at either dose compared to placebo, supporting the safety of normal supplemental amounts.

Blood Sugar and Metabolic Research

The chlorogenic acids in guayusa inhibit glucose-6-phosphatase, one of the enzymes controlling glucose release from the liver — the same mechanism that gives coffee its modest blood-sugar-lowering effects [3]. Preclinical research in streptozotocin-induced diabetic rats found that guayusa tea provided ad libitum over three weeks improved glycemic markers and autonomic cardiovascular regulation [5]. These are early data in an animal model, but the mechanism is plausible and consistent with what is known about chlorogenic acids generally.

Brewing and Practical Use

Traditional preparation involves simmering dried leaves for 10–15 minutes at lower temperatures than boiling. As a brewed tea, 2–3 grams of dried leaf per 250 ml cup is a common starting point. Commercially, guayusa is available as loose-leaf, tea bags, and concentrated extracts — the 2024 clinical trial used a 600–1,200 mg standardized extract, roughly equivalent to 2–4 cups of moderately strong brewed guayusa.

Guayusa is considered safe based on its long history of use in Ecuador, its low toxicology profile reviewed by Wise and Negrin (2020), and the absence of adverse cardiovascular signals in the controlled human trial [3][4]. Individuals sensitive to caffeine should apply the same caution as with other caffeinated beverages.

See our green tea page for EGCG catechin-based antioxidant benefits, and our matcha page for the highest-concentration catechin source among teas.

Evidence Review

Phytochemical Characterization (García-Ruiz et al., 2017)

García-Ruiz and colleagues published the first systematic phytochemical analysis of guayusa as a commercial tea product [1]. Using HPLC-DAD-ESI-MS, they identified 14 phenolic compounds and five carotenoids in guayusa leaves. Chlorogenic acid and quercetin-3-O-hexose were quantitatively dominant among the phenolics, while lutein was the most concentrated carotenoid. Antioxidant capacity measured by DPPH and ORAC assays confirmed high radical-scavenging activity consistent with the chlorogenic acid content.

The study situated guayusa within the emerging category of caffeinated botanical beverages and provided a composition baseline for comparing guayusa to established teas. The carotenoid content is notable given that few hot-brewed beverages contribute meaningful lutein intake.

Antioxidant and Anti-inflammatory Activity vs. Green and Black Tea (Pardau et al., 2017)

Pardau et al. conducted the most direct comparison of guayusa with conventional teas using standardized in vitro and cellular assay models [2]. Three guayusa tea preparations (varying brew strength and temperature) were compared against green and black Camellia sinensis teas. Total polyphenolic content of guayusa ranged from 54–67 mg GAE per gram dry mass, roughly half the values seen in green tea but within the range of some black tea preparations.

In the Caco-2 cellular antioxidant assay — which measures protection against peroxyl radical damage inside intestinal cells — guayusa afforded 60–80% protection, comparable to the Camellia sinensis preparations. Anti-inflammatory activity was assessed by measuring nitric oxide production in LPS-stimulated RAW 264.7 macrophages. Guayusa reduced nitric oxide by 10–30%, broadly similar to the green and black teas tested.

The key mechanistic distinction: guayusa's antioxidant activity is primarily driven by caffeoylquinic acid derivatives (mono- and dicaffeoylquinic acids identified by mass spectrometry), not catechins. This means it may access antioxidant pathways that are distinct from EGCG-mediated mechanisms of green tea.

Safety Review (Wise and Negrin, 2020)

This critical review analyzed guayusa's ethnobotanical history, chemical profile, and toxicological data as part of a novel food safety assessment for the European market [3]. Key conclusions:

Guayusa has been consumed continuously in Ecuador for at least several hundred years, with no documented historical adverse effects
Acute and chronic toxicology studies in rodents showed no genotoxicity, mutagenicity, or organ-level harm at doses far exceeding normal dietary intake
The methylxanthine, chlorogenic acid, and flavonoid profile presents no known risks beyond those associated with caffeine itself
The review recommended standard caffeine advisories (pregnancy, caffeine sensitivity) apply equally to guayusa

The authors noted that guayusa's chemical profile is still less thoroughly characterized than green tea, and called for further work on bioavailability and specific effects of its caffeoylquinic acid compounds in humans.

Human Randomized Crossover Trial: Cognitive and Mood Effects (Helwig et al., 2024)

This is the most rigorous human evidence to date for guayusa's cognitive effects [4]. The study enrolled 25 healthy adults (mean age 28, 9 male/16 female) in a randomized, double-blind, placebo-controlled crossover design. Participants received 600 mg GLE, 1,200 mg GLE, or placebo at three separate visits, with a washout between visits.

Outcomes at 60 minutes post-ingestion:

600 mg GLE: Significantly lower total mood disturbance (POMS-SF; p < 0.05), reduced fatigue-inertia subscale (p < 0.05), improved perceived energy and focus (p < 0.05), faster choice reaction time (p < 0.05), and faster motor speed (p < 0.05) vs. placebo
1,200 mg GLE: Additionally reduced reaction time in a neurocognitive hop test, supporting motor-cognitive benefits at higher doses
Cardiovascular safety: No significant differences in blood pressure, heart rate, or QT interval vs. placebo at either dose, suggesting the extract does not carry excess cardiovascular risk at these amounts

The study's limitations include a single-visit acute design (no chronic use data), a relatively young and healthy sample, and that the extract concentration may not directly translate to specific amounts of brewed tea. Nonetheless, this is the first placebo-controlled human trial demonstrating dose-dependent cognitive benefits from guayusa supplementation.

Glycemic Effects in an Animal Model (Peçanha de Miranda Coelho et al., 2025)

A Brazilian research group investigated whether guayusa tea could affect glycemia and autonomic cardiovascular control in streptozotocin-induced diabetic female rats [5]. Diabetic rats given guayusa tea ad libitum for 21 days showed improvements in glycemic markers and in sympathovagal cardiovascular balance compared to diabetic controls. Specifically, guayusa was associated with higher values of α1 (a sympathetic modulation index of systolic arterial pressure) and variance in systolic arterial pressure, with a significant inverse correlation between final glucose and vascular variability (r = −0.81, p = 0.002).

These preclinical results suggest guayusa may modulate the autonomic nervous system dysfunction that accompanies chronic hyperglycemia. The study is limited by the animal model (STZ-induced diabetes differs mechanistically from type 2 diabetes) and small sample size (n = 13). Human evidence for guayusa's blood sugar effects is currently lacking.

Overall Evidence Assessment

The evidence base for guayusa is still developing. The antioxidant and anti-inflammatory profile is well-characterized and comparable to green tea in laboratory conditions. Safety data is reassuring. The 2024 human trial establishes plausible cognitive benefits at moderate supplemental doses. Glycemic effects in humans remain unconfirmed.

The strongest practical take: guayusa is a safe and antioxidant-rich caffeinated beverage with a favorable stimulant profile (caffeine + theobromine), meaningfully supported by phytochemical evidence and one well-designed human trial. It is not a replacement for the more extensively studied green tea, but it offers a distinct compound profile and may particularly appeal to those who find coffee or yerba mate too harsh.

References

Guayusa (Ilex guayusa L.) new tea: phenolic and carotenoid composition and antioxidant capacityGarcía-Ruiz A, Baenas N, Benítez-González AM, Stinco CM, Meléndez-Martínez AJ, Moreno DA, Ruales J. Journal of the Science of Food and Agriculture, 2017. PubMed 28188617 →
Antioxidant and anti-inflammatory properties of Ilex guayusa tea preparations: a comparison to Camellia sinensis teasPardau MD, Pereira ASP, Apostolides Z, Serem JC, Bester MJ. Food & Function, 2017. PubMed 29134218 →
A critical review of the composition and history of safe use of guayusa: a stimulant and antioxidant novel foodWise G, Negrin A. Critical Reviews in Food Science and Nutrition, 2020. PubMed 31366209 →
Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarizationHelwig NJ, Johnson EC, Lande A, Lande PJ, Smith CR, Smith CL. Journal of the International Society of Sports Nutrition, 2024. PubMed 39014963 →
Ilex Guayusa Tea Improves Glycaemia and Autonomic Modulation in Female Streptozotocin-Induced Diabetic RatsPeçanha de Miranda Coelho JA, Rossi RC, Vieira FT, Llesuy S, da Silva Neto CR, Bosi Ferraz MM. Pharmaceuticals, 2025. Source →