Browse the site

Start with a goal 40 things people take supplements for — sleep, stress, joints, focus.
Home Get the app
Guayusa

Guayusa

Best for

Sharpen focus

Faint early signal 600–1200 mg/day 2 studies, n=130 #10 of 31 studied

  • 2 papers
  • 2 of 11 outcomes
  • 2 positive

Guayusa shows a faint early signal for longer-lasting focus, while evidence for stamina remains too limited to support a meaningful energy or productivity boost.

Median effective dose, most-studied outcomes

  • Hold focus through repetitive work 650 mg —
  • Have less fatigue 600 mg —
Full protocol, 2 outcomes

Risk, worst reported severity

  • dry mouth mild
  • tremor mild
All 4 events and interactions

What guayusa actually does

Outcome Effect Evidence Dose Time Rank
Early research 2
Sharpen focus Faint early signal Focus helps you stay with a task instead of being pulled away by distractions.
small 		2 RCTs 2 papers · n=130 600–1200 mg — #10 /31
Feel less tired every day Barely detectable Everyday energy helps you get through daily tasks without feeling worn down.
trivial 		1 RCT 1 papers · n=50 600–1200 mg — —

Effect tiers come from native-unit MCID where available, Cohen's d otherwise.

Protocol

Dose, timing & forms

How much

The small body of human research used oral guayusa products in the 600 to 1,200 mg/day range for focus stamina and everyday fatigue. Focus has the better, though still early, signal, with a median effective amount near 650 mg/day across the reviewed trials.2 Treat this as research context rather than a proven target, since the observed effects range from small for focus to trivial for fatigue.2

When and how long

The available evidence does not establish whether a single serving, split doses, taking it with food, or a particular time of day produces better results.2 Since guayusa supplies caffeine, use it when alertness is useful and protect your sleep by keeping it away from bedtime if you are caffeine-sensitive.1 Consistency matters more than chasing a quick boost if you are testing whether it changes your focus over time.2

Forms & standardisation

Human research does not yet identify a best guayusa extract, leaf preparation, or active-compound standardization.2 A label that clearly states caffeine per serving gives you a more useful way to compare products than a vague “energy blend,” because caffeine is the best-established alertness-related constituent.1 Avoid assuming that a concentrated extract has the same effects as traditionally brewed leaf tea.

Studied range, by outcome

Outcome Studied range Median effective Duration Evidence
Hold focus through repetitive work 600–1,200 mg 650 mg — 2 papers 3 sig. endpoints
Have less fatigue 600–1,200 mg 600 mg — 1 paper 1 sig. endpoint

Adverse events and drug interactions

Safety events

dry mouth mild
tremor mild
headache mild
upper respiratory tract infection
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.

In context

What this is and how it works

  • Across 2 studies (n=130), guayusa improved six focus endpoints, but the reported effect size and noticeable-change threshold were unavailable.2
  • Two papers reviewed here span 11 outcomes, including one small stamina study involving 50 participants.2
  • Early evidence comes from only two papers, leaving guayusa’s broader effects uncertain.

Guayusa is a caffeinated leaf from Ilex guayusa, a holly species native to the western Amazon. People traditionally steep the leaves as a tea, and modern products also sell them as powders, capsules, and extracts.13

Guayusa contains caffeine, which blocks adenosine, the brain signal that builds up pressure to sleep. Picture adenosine as a growing stack of “time to rest” notifications. Caffeine mutes those notifications for a while, which can make you feel more alert.1 The small guayusa studies leave open an important question: whether the leaf delivers anything beyond the familiar effect of caffeine itself.2

Bottom line

Guayusa suits people who enjoy caffeinated tea and want to test a modest, early signal for staying on task. Do not buy it expecting a dramatic energy or productivity change, because the focus effect is small and the fatigue finding barely registers.2 Skip it or use extra caution if caffeine brings on tremor, headaches, dry mouth, or disrupted sleep.

Frequently asked

Common questions

Does guayusa improve focus?

Early research shows a faint, small signal that guayusa supports focus stamina during demanding or repetitive work. That is not enough evidence to promise a noticeable result for most people, especially because only two studies inform this question.2

Does guayusa give you energy?

One early study found only a trivial change in everyday fatigue. Think of guayusa as a caffeinated drink that some people find alerting, not an established solution for low energy.12

When should you take guayusa?

The current clinical evidence does not establish a best time of day or a proven schedule. If caffeine affects your sleep, use guayusa earlier in the day and avoid treating it like an evening focus aid.12

Is guayusa the same as yerba mate?

No. Both come from South American holly relatives and contain caffeine, but guayusa is Ilex guayusa, while yerba mate is a different plant species.3

Sources

Sources

  1. 1. Caffeine
  2. 2. PubMed search: Ilex guayusa clinical research
  3. 3. Plants of the World Online: Ilex guayusa Loes.

Generated August 27, 2026

Related

More evidence for Guayusa