Guaraná Supplementation for Cancer-Related Fatigue

Cancer-related fatigue is one of the most common and distressing symptoms experienced by patients during and after cancer treatment, and current options to manage it are limited. Guaraná (Paullinia cupana), an Amazonian plant rich in caffeine and other methylxanthines with anti-inflammatory and central-nervous-system-stimulating properties, has shown preliminary benefit for fatigue in small studies but lacks robust evidence. This pragmatic, prospective, single-arm study will evaluate whether guaraná supplementation reduces chronic cancer-related fatigue and improves quality of life in 60 patients with breast, lung, colorectal, or gastric cancer receiving active systemic treatment. Participants will take a 50 mg guaraná capsule by mouth every 12 hours for up to six 21-day cycles. The main outcome is the change in fatigue (baseline vs. post-intervention) measured with the FACIT-F and the Brief Fatigue Inventory (BFI). Secondary outcomes include quality of life (EORTC QLQ-C30) and adverse events. The study aims to support guaraná as a safe, accessible complementary option in supportive cancer care.