PEP Topic 

Guarana (Paullinia cupana) is a plant native to the central Amazon that has been used medicinally for centuries. It has a popular reputation as a stimulant and aphrodisiac and of providing gastric-protective effects. Guarana contains caffeine and similar chemicals. Guarana has been used to treat diarrhea, weight loss, and fatigue. Evaluation of its use for patients with cancer has related to symptoms of fatigue, sleep-wake disturbances, and depression.

Effectiveness Not Established

Research Evidence Summaries

da Costa Miranda, V., Trufelli, D.C., Santos, J., Campos, M.P., Nobuo, M., da Costa Miranda, M., … del Giglio, A. (2009). Effectiveness of guarana (Paullinia cupana) for postradiation fatigue and depression: Results of a pilot double-blind randomized study. Journal of Alternative and Complementary Medicine, 15, 431–433.


Study Purpose:

To evaluate the effectiveness of guarana in the treatment of the fatigue and depression of patients with breast cancer who are undergoing adjuvant radiation therapy

Intervention Characteristics/Basic Study Process:

Guarana, a plant native to the central Amazon, is known for its stimulant properties. The study involved three phases. Investigators randomized patients at the start of adjuvant radiation treatment (RT) to either guarana or placebo (phase 1). Halfway through RT, crossover occurred from placebo to guarana and vice versa (phase 2). Protocol terminated at end of the 28th RT (phase 3) for both groups. Assessments occurred three times, once at the start of each phase. The total time of the trial was 35 days. A dose of 75 mg/day guarana was administrated.

Sample Characteristics:

  • The sample was comosed of 36 participants. In Group A, 17 participants received guarana first, then switched to placebo. In Group B, 19 received placebo first then switched to guarana.
  • Mean patient age in Group A was 59 years; in Group B, 57 years.
  • All participants were female and had infiltrating ductal breast cancer. All patients had undergone mastectomy and were receiving adjuvant RT. Authors state that most participants had stage I or II cancer, but they do not provide a table of sample characteristics. 


  • Single site
  • Outpatient
  • Brazil

Phase of Care and Clinical Applications:

Active treatment

Study Design:

Double-blind randomized design with crossover

Measurement Instruments/Methods:

  • Chalder Fatigue Scale (CFS)
  • Brief Fatigue Inventory (BFI), in Portuguese
  • Beck Depression Inventory-II (BDI-II), validated in Portuguese


  • Authors reported no statistically significant differences between the guarana- and placebo-treated group, on any of the measures of fatigue or depression.
  • Authors reported no significant differences within groups over time or in different treatment arms, placebo or guarana.
  • Authors noted no toxic effects of guarana.
  • Participants in neither group had significant fatigue or depression at the start of the trial. Showing the improvement of a nonexistent symptom is impossible, according to the so-called floor effect.


Findings did not support the use of guarana for the treatment of depression or fatigue in cancer patients.


  • The study had a small sample, with fewer than 30 participants. Conclusions drawn from such a small sample may not be valid.
  • The study was likely underpowered in regard to detecting group differences.
  • Participants did not demonstrate significant symptoms at baseline. A better course may be to select either patients at risk for fatigue and depression or a sample of individuals already presenting with such symptoms, to see if treatment results in improvement.

Nursing Implications:

Due to the limitations noted, this study does not support valid nursing conclusions.