YahGarden

Herb library · Herb · Ilex guayusa

Guayusa

A holly tree of the upper Amazon whose caffeine-rich leaves are brewed like tea. It is an everyday drink of Kichwa families in Ecuador and is now sold worldwide; two small trials found short-term effects on alertness and a small rise in blood pressure.

Traditional use

Among Kichwa families of Napo province in Ecuador, guayusa has long been a central part of daily and family life. A 2026 study of Kichwa households found that the leaves are still grown and brewed at home, and that people value the drink for keeping sleepiness, tiredness, body aches and hunger away. Its use has spread beyond the family as export demand for the leaf has grown.

What studies show

  • Limited

    Alertness and mood: in two small randomized, placebo-controlled crossover trials in adults (one with 25 people), a single dose of guayusa leaf extract improved some measures of mood, energy and reaction time over the next hours. These were one-time doses of an extract that contains caffeine, so they say little about drinking the tea over time.

  • Limited

    Blood pressure: in both trials the extract raised blood pressure; in one, both doses raised it by about 4 to 5 points, and jitteriness rose with the dose in women.

Be careful of

Cautions

  • NoteGuayusa contains caffeine. Count it toward your caffeine for the day, and avoid it late in the day if caffeine keeps you awake. A 2020 safety review judged the leaf no riskier than green tea or yerba mate, based on its chemistry and long history as a drink.
  • ConditionIt raised blood pressure in both trials. If you have high blood pressure, heart rhythm problems or anxiety, talk with a clinician first.
  • PregnancyCaffeine limits in pregnancy apply to guayusa; talk with your clinician.
  • Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, especially stimulants or medicines that interact with caffeine, or are pregnant or breastfeeding.

Sources

  1. Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization (J Int Soc Sports Nutr, 2024) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  2. Acute Effects of Naturally Occurring Guayusa Tea and Nordic Lion's Mane Extracts on Cognitive Performance (Nutrients, 2023) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  3. A critical review of the composition and history of safe use of guayusa: a stimulant and antioxidant novel food (Crit Rev Food Sci Nutr, 2020) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  4. Socio-cultural components related to the cropping, harvesting, and consumption of guayusa (Ilex guayusa Loes) in Amazonian Kichwa communities (PLoS One, 2026) — PubMed record (opens in a new tab) · NIH · read September 25, 2026

Reviewed September 25, 2026.