Last verified: today
Guayusa Leaf
Also known as: Ilex guayusa, Amazonian holly, guayusa tea
Evidence under review. — Not yet rated
Amazonian tea leaf with caffeine and antioxidants. Limited clinical research; mostly traditional use.
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What it does
Guayusa is a caffeinated leaf from the Amazonian holly tree, traditionally brewed as a tea by indigenous peoples of Ecuador and Peru. It naturally contains caffeine, theobromine, and antioxidant...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
No established dose
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Found in
What the Science Says
Guayusa is a caffeinated leaf from the Amazonian holly tree, traditionally brewed as a tea by indigenous peoples of Ecuador and Peru. It naturally contains caffeine, theobromine, and antioxidant compounds called polyphenols, which may support alertness and provide antioxidant activity similar to other caffeinated botanicals. Because no clinical trial abstracts were available for this analysis, any specific health benefit claims beyond general caffeine effects remain unverified by published research.
What It Doesn't Do
Not proven to be superior to coffee or green tea for energy. No clinical evidence it burns fat on its own. 'Clean energy' marketing is mostly about caffeine — same stimulant found in coffee. No proven nootropic edge beyond basic caffeine effects. Not a substitute for medical treatment of fatigue or cognitive decline.
Evidence-Based Benefits
Provides a caffeine-driven boost in alertness, similar to other caffeinated teas.
Weak EvidenceEffective at: No established dose
Contains polyphenols that may offer antioxidant protection in the body.
Weak EvidenceEffective at: No established dose
Absorption & Bioavailability
Unknown — no pharmacokinetic studies were available. Caffeine from plant sources is generally well absorbed orally, but guayusa-specific absorption data is lacking.
Red Flags to Watch For
- Contains caffeine — can cause anxiety, insomnia, elevated heart rate, or jitteriness, especially in sensitive individuals or when combined with other stimulants
- Very limited published clinical research; most health claims are based on traditional use or marketing, not controlled trials
- Products vary widely in caffeine content with no standardized dosing — risk of unintentional overconsumption
- May interact with stimulant medications, blood thinners, or medications metabolized by the liver due to polyphenol content
Products Containing Guayusa Leaf
See how Guayusa Leaf is used in these analyzed products:
Research Sources
- General knowledge — Limited published research available
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25