Guayusa

Best for

Sharpen focus and mental stamina

Promising early signal · 650–1200 mg/day · 2 studies , n=130

2 papers · 2 claims · 15 outcomes scored · 2 positive

Outcomes

What guayusa actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Sharpen focus and mental stamina Promising early signal

Concentrate longer, resist distraction, and stay mentally sharp through demanding tasks.

2 RCTs n=130 650–1200 mg —

39014963·38140277

moderate

2 RCTs n=130

650–1200 mg

—

Reduce everyday fatigue Faint early signal

Less of that heavy, worn-out feeling that makes simple tasks feel like a chore.

1 RCT n=50 1200 mg — #9/44

39014963

small

1 RCT n=50

1200 mg

—

#9 /44

Outcome	Effect	Evidence	Dose	Weeks	Rank
Sharpen focus and mental stamina Promising early signal	moderate	2 RCTs n=130	650–1200 mg	—	—
Reduce everyday fatigue Faint early signal	small	1 RCT n=50	1200 mg	—	#9/44

Buy well

Recommended Guayusa products

Real products that dose Guayusa where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Guayusa dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

dry mouth mild

tremor mild

headache mild

upper respiratory tract infection

Sources

Generated August 14, 2026

Guayusa

What guayusa actually does, by outcome

Recommended Guayusa products

Adverse events and known drug interactions

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Citicoline

Coffee

Creatine

Ginkgo