Guarana
Also sold as: Paullinia cupana · Guarana seed extract · Brazilian cocoa
A caffeine-containing seed used in energy, focus and sports products. Extract percentages vary, so botanical mass alone does not tell you the caffeine exposure.
Energy Focus Anxiety
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Research
- Focus: A small low-dose extract study was positive, but a 500 mg extract versus caffeine study was null; multi-ingredient products limit attribution.
- Anxiety: No established isolated-guarana anxiety benefit. Small mixed-product studies cannot prove it, and caffeine-related stimulation may aggravate anxiety in susceptible users.
- Energy: Small acute sports studies report trivial-to-small signals, without proven superiority to caffeine. Cancer-fatigue trials and meta-analyses conflict and do not generalize to healthy users.
REALITY CHECK // Guarana is not caffeine-free energy, and controlled slow-release superiority has not been established. Small acute studies mix positive and null findings, while cancer-fatigue meta-analyses disagree. The main label task is identifying and adding up actual caffeine, not treating every gram of guarana as equivalent.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
UPPER LIMIT // No guarana-specific numerical UL is established. The dossier cites EFSA caffeine safety guidance of up to 400 mg/day and 200 mg per single intake for healthy adults, and up to 200 mg/day during pregnancy/breastfeeding. These are caffeine assessments, not guarana ULs or guarantees for sensitive individuals; sum caffeine from all sources. Youth figures in the dossier are not a recommendation to use guarana.
Summary
Guarana is a variable caffeine source with some small and inconsistent clinical signals. A 75 mg extract study suggested acute cognitive benefit, whereas a 500 mg study did not; sports superiority over caffeine is unproved. Cancer-fatigue findings conflict, and weight-loss combination trials cannot establish efficacy of guarana alone.
Mechanism
Caffeine and other methylxanthines contribute to stimulation, while seed flavonoids provide mechanistic hypotheses. A low-caffeine-dose signal suggests a possible noncaffeine contribution but does not establish it. Antioxidant and anti-inflammatory mechanisms are not proof of clinical disease prevention.
Typical studied dose
One healthy-volunteer cognitive study used 75 mg extract at about 12% caffeine (about 9 mg caffeine). A later acute study used 500 mg guarana providing 130 mg caffeine versus 100 mg caffeine and found no reaction-time, mood or vagal effect. Cancer fatigue: 50 mg twice daily in one positive 21-49 day study. Cycling: 500 mg before exercise; a separate U-17 soccer trial used 3 g seed material. These preparations and populations are not interchangeable.
Upper limit
No guarana-specific numerical UL is established. The dossier cites EFSA caffeine safety guidance of up to 400 mg/day and 200 mg per single intake for healthy adults, and up to 200 mg/day during pregnancy/breastfeeding. These are caffeine assessments, not guarana ULs or guarantees for sensitive individuals; sum caffeine from all sources. Youth figures in the dossier are not a recommendation to use guarana.
Popular stacks with Guarana
Not enough stack data yet. A combination with Guarana appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| Guarana extract labeled 12% caffeine Best for: Checking the same 12% extract specification against the low-dose acute study. |
Extract weight · ~12% marker | 75–75 mg | A small acute cognitive study used this extract specification; superiority over caffeine is not established. Caffeine stimulation and gastrointestinal tolerance depend on the person and other sources. |
Studied standard [REFERENCE // STUDIED_FORM] Compare FULL extract mass with the 75 mg study amount. The 12% marker displays caffeine content (75 mg x 0.12 = 9 mg); it does not rescale the extract target or show bioavailability. |
| Guarana extract labeled 22% caffeine Best for: Reading a declared caffeine percentage without assuming a 12% trial applies. |
Unstandardized: active content unknown | no comparable trial range | More concentrated caffeine than a typical raw seed powder; no matching product-specific trial target is supplied. Lower botanical mass does not eliminate caffeine intolerance. |
Caution [CAUTION // CHECK_BASIS] A 22% label is a composition specification, not a studied equivalent to the 12% extract. No trial-dose interval is inferred; zero denotes unavailable. |
| Whole guarana seed powder: caffeine not batch-verified Best for: Recognizing variable caffeine exposure rather than assuming a universal 4% value. |
Unstandardized: active content unknown | no comparable trial range | Seed matrix contains tannins and fiber; a controlled slow-release advantage remains unproved. Larger amounts may cause stomach discomfort, particularly when taken fasting. |
Caution [CAUTION // CHECK_BASIS] The dossier reports roughly 2-6% caffeine across seeds. Without a batch declaration use unknown, not the 4% midpoint as a verified conversion. |
| Guarana in energy drinks, shots and fat-loss blends Best for: Detecting hidden or double-counted caffeine across a mixed product. |
Unstandardized: active content unknown | no comparable trial range | Caffeine may come from several ingredients; total labeled caffeine matters more than guarana mass. Depends on the full formulation; unintended stimulant stacking is the main risk. |
Caution [CAUTION // CHECK_BASIS] Do not treat a blend as 100% guarana or 100% caffeine. No single generic mg trial target or conversion is valid for a multi-ingredient product. |
Common label traps
- TRAP_01 // Natural energy without caffeine
Guarana is caffeine-containing. Seed powder and concentrated extract percentages differ, so the plant name does not identify exposure. - TRAP_02 // Slow release without jitters or a crash
This common marketing claim lacks rigorous controlled support in the dossier. Anxiety and sleep effects still depend on caffeine exposure and susceptibility. - TRAP_03 // Guarana beats caffeine
The small cycling study showed a trivial-to-small placebo comparison but did not establish a difference from caffeine; the acute mental-performance comparison was null. - TRAP_04 // A proven stand-alone fat burner
Historical weight-loss studies combined guarana with ephedra or other herbs. The ingredient cannot inherit the whole combination effect, and stimulant combinations carry safety concerns.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- CANCER-RELATED FATIGUE Limited · benefit
A 75-person crossover breast-cancer study at 50 mg twice daily was positive at days 21/49. A 2021 meta-analysis (7 studies, 427 patients) found no pooled breast-cancer difference across three studies: mean -0.02, 95% CI -1.54 to 1.50, p=0.98; very-low certainty. A 2024 meta-analysis was favorable. This is conflicting oncology evidence.
PMID 21612429 PMID 34146166 PMID 39536249 PMID 29190155 PMID 24237188 PMID 19388866 PMID 29915949 - ACUTE COGNITION / MIXED RESULTS Limited · benefit
A 28-person study found attention/serial-subtraction signals with 75 mg of approximately 12% extract. In a 20-person later study, 500 mg guarana/130 mg caffeine did not improve reaction time, mood or vagal modulation versus comparators. Multivitamin products cannot isolate guarana.
PMID 15582012 PMID 18077056 PMID 38931247 PMID 23706111 - CYCLING TIME TRIAL Limited · benefit
In 11 participants, 500 mg guarana improved work versus placebo with effect size 0.18 (95% CI 0.003-0.355, p=0.046), but the caffeine comparison was not significant (p=0.079). No superiority over caffeine was established.
PMID 37898479 - SOCCER PERFORMANCE / YOUTH STUDY Limited · benefit
In 27 U-17 players, 3 g improved Yo-Yo IR1 distance (p=0.01), without jump, sprint or agility benefit. A small youth exercise trial is not authorization for routine youth stimulant supplementation.
PMID 38958672 - WEIGHT LOSS / SOLO CLAIM No established evidence
Historical RCTs tested combinations, including ephedra-guarana or multiple herbs. No established isolated-guarana weight-loss benefit follows; this means unestablished efficacy, not a definitive negative solo trial.
PMID 11319627 PMID 11424516 PMID 26612980 PMID 15836459 - ANXIETY / MIXED-PRODUCT TRIALS Limited · no benefit
A weak/negative commercial-product trial and an old multi-extract anxiety study do not establish guarana-alone anxiolysis. Caffeine-related agitation remains a precaution.
PMID 23706111 PMID 9107558 - ANTIOXIDANT / ANTI-INFLAMMATORY CLAIMS No established evidence
Narrative and preclinical mechanisms do not establish hard human health outcomes from guarana supplementation. Unestablished clinical benefit is distinct from a proven negative disease trial.
PMID 34755935 PMID 38916807
Reader questions
Is guarana slower and smoother than coffee?
That is a common user report, but controlled slow-release superiority is not established. Compare actual caffeine exposure and the rest of the formulation rather than relying on the plant name.
How much caffeine is in a gram?
Only a declared, batch-relevant percentage can answer reliably. A 12% extract contains 120 mg/g, and a 22% extract 220 mg/g; whole-seed material varies approximately 2-6% in this dossier. These are composition calculations, not dose recommendations.
Does guarana work better than caffeine anhydrous?
Small acute trials are inconsistent. The cycling study did not establish superiority over caffeine, and the mental-performance comparison was null; the low-dose cognitive signal needs replication.
Can I combine it with St John's wort or 5-HTP?
Have the medication/supplement combination reviewed. The dossier does not establish a specific serotonin-syndrome interaction from a guarana RCT; fluvoxamine-related caffeine accumulation and additive stimulation are more concrete concerns.
Does it help weight loss?
There is no isolated-guarana evidence establishing meaningful weight loss here. Combination trials, especially those using ephedra, do not answer that question and bring different risks.
Why does guarana sometimes make me sleepy?
Variable exposure, sleep loss and tolerance may be relevant, but the supplied studies do not establish the cause of an individual paradoxical response. Persistent fatigue should not be managed by continually increasing stimulant intake.
Stack interactions
- Caution Coffee, tea, preworkouts and energy drinks [CAUTION // CLINICAL_REVIEW]
Add caffeine from every source, including guarana and caffeine anhydrous in the same formula. Overlapping products can cause unexpected exposure; botanical origin does not reduce caffeine risk.
PMID 21037046 PMID 36862943 - Caution Fluvoxamine, ciprofloxacin and estrogen therapy [CAUTION // CLINICAL_REVIEW]
The dossier describes slower caffeine clearance and therefore longer or stronger effects. This is a caffeine-related review warning, not a quantified guarana-product interaction trial.
PMID 22675703 - Danger Ephedrine-like products and other stimulants [CAUTION // CLINICAL_REVIEW]
Combining stimulants can increase cardiovascular burden. The ephedrine/caffeine myocardial-necrosis study is in rats; it supports a hazard concern, not a quantified human event rate.
PMID 15537744 PMID 11319627 - Caution Cardiovascular treatment / arrhythmia risk [CAUTION // CLINICAL_REVIEW]
Reports of cardiovascular adverse reactions justify medication and disease review. A case-based signal cannot establish incidence or prove that every guarana exposure causes arrhythmia.
PMID 15277107 PMID 20633025 - Caution L-theanine calming stacks [CAUTION // CLINICAL_REVIEW]
Common user practice does not prove that theanine neutralizes guarana cardiovascular or sleep effects. It does not remove the need to count total caffeine.
Red flags: interactions and who should avoid it
Interactions
Other caffeine or stimulant sources add to exposure. Fluvoxamine, ciprofloxacin and estrogen-containing therapy can slow caffeine clearance; medication review matters. Stimulant combinations, especially ephedrine-like products, can compound cardiovascular effects. Broad serotonin-syndrome claims for guarana with St John's wort or 5-HTP are not established by a direct interaction trial here. Caffeine can transiently affect glucose control in treated diabetes.
Avoid or ask a doctor first if
Avoid unsupervised use with arrhythmia, cardiovascular disease, uncontrolled blood pressure, panic/anxiety disorders, insomnia, hyperthyroid symptoms or a sensitive reflux/ulcer-prone stomach. Unknown caffeine content is particularly unsuitable in pregnancy/breastfeeding and children. Excess exposure can cause palpitations, tremor, anxiety, sleep disruption and gastrointestinal symptoms; persistent tachycardia, chest symptoms or fainting need prompt medical assessment. Regular use may produce tolerance and withdrawal headache.
Sources (PubMed, 26)
- Guarana (Paullinia cupana) improves fatigue in breast cancer patients undergoing systemic chemotherapy.
PMID 21612429 · 2011 · randomized controlled trialPositive 50 mg twice-daily cancer-fatigue crossover trial, n=75, selected breast-cancer population.
- The use of guarana (Paullinia cupana) as a dietary supplement for fatigue in cancer patients: a systematic review with a meta-analysis.
PMID 34146166 · 2021 · systematic review / meta-analysisConflicting 2021 cancer-fatigue synthesis: three-study breast-cancer pool null, very-low certainty.
- Natural supplementation to effectively treat cancer-induced fatigue: evidence of a meta-analysis on the use of guaraná.
PMID 39536249 · 2024 · systematic review / meta-analysis2024 cancer-fatigue meta-analysis with favorable findings, conflicting with the earlier synthesis.
- Purified Dry Paullinia cupana (PC-18) Extract for Chemotherapy-Induced Fatigue: Results of Two Double-Blind Randomized Clinical Trials.
PMID 29190155 · 2018 · randomized controlled trialTwo purified-extract chemotherapy-fatigue trials contribute to a mixed oncology evidence base.
- Purified dry extract of Paullinia cupana (guaraná) (PC-18) for chemotherapy-related fatigue in patients with solid tumors: an early discontinuation study.
PMID 24237188 · 2013 · randomized controlled trialEarly-discontinuation solid-tumor fatigue trial, limiting certainty.
- Effectiveness of guaraná (Paullinia cupana) for postradiation fatigue and depression: results of a pilot double-blind randomized study.
PMID 19388866 · 2009 · randomized controlled trialPilot postradiation fatigue/depression trial; selected clinical setting.
- Dietary supplements and fatigue in patients with breast cancer: a systematic review.
PMID 29915949 · 2018 · systematic review / meta-analysisBreast-cancer supplement/fatigue systematic review; oncology scope.
- Improved cognitive performance in human volunteers following administration of guarana (Paullinia cupana) extract: comparison and interaction with Panax ginseng.
PMID 15582012 · 2004 · randomized controlled trialSmall 75 mg approximately 12%-caffeine extract cognitive study; no general clinical efficacy inference.
- Improved cognitive performance and mental fatigue following a multi-vitamin and mineral supplement with added guaraná (Paullinia cupana).
PMID 18077056 · 2008 · randomized controlled trialMultivitamin/mineral plus guarana cognitive-fatigue study; attribution to guarana alone limited.
- Effects of Acute Guarana (Paullinia cupana) Ingestion on Mental Performance and Vagal Modulation Compared to a Low Dose of Caffeine.
PMID 38931247 · 2024 · randomized controlled trial500 mg guarana/130 mg caffeine acute mental-performance comparison with null findings in the dossier.
- Effects of a commercial product containing guaraná on psychological well-being, anxiety and mood: a single-blind, placebo-controlled study in healthy subjects.
PMID 23706111 · 2013 · randomized controlled trialSmall commercial-product study with weak/negative mood/anxiety findings.
- Guarana (Paullinia cupana) but Not Low-Dose Caffeine Improves Cycling Time-Trial Performance Versus Placebo.
PMID 37898479 · 2024 · randomized controlled trialSmall cycling trial: trivial-to-small placebo difference without established superiority over caffeine.
- Effects of Acute Ingestion of Guarana (Paullinia Cupana) on Soccer Player Performance: A Randomized, Cross-over, Placebo-Controlled Study.
PMID 38958672 · 2024 · randomized controlled trialU-17 soccer crossover study: Yo-Yo distance signal but no jump/sprint/agility benefit.
- An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial.
PMID 11319627 · 2001 · randomized controlled trialEphedra-guarana combination weight-loss trial, not guarana monotherapy.
- Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients.
PMID 11424516 · 2001 · randomized controlled trialMulti-herb weight-loss/gastric-emptying trial; cannot isolate guarana.
- Acute effectiveness of a \"fat-loss\" product on substrate utilization, perception of hunger, mood state and rate of perceived exertion at rest and during exercise.
PMID 26612980 · 2015 · randomized controlled trialCommercial fat-loss combination acute study; not a solo weight-loss efficacy test.
- Adverse events of herbal food supplements for body weight reduction: systematic review.
PMID 15836459 · 2005 · systematic review / meta-analysisHerbal weight-loss adverse-event systematic review; combination safety context.
- A combination of plant extracts in the treatment of outpatients with adjustment disorder with anxious mood: controlled study versus placebo.
PMID 9107558 · 1997 · randomized controlled trialOld multi-extract anxious-mood trial; cannot establish isolated-guarana benefit.
- Effects of the consumption of guarana on human health: A narrative review.
PMID 34755935 · 2022 · narrative reviewNarrative review of methylxanthines/flavonoids and limited human clinical translation.
- Amazonian Fruits for Treatment of Non-Communicable Diseases.
PMID 38916807 · 2024 · narrative reviewAmazonian-fruit narrative review, not a guarana clinical efficacy trial.
- Guarana: Paullinia cupana, P. sorbilis; also known as Brazilian cocoa and 'zoom'.
PMID 22675703 · 2012 · narrative reviewClinical review of guarana labeling, caffeine content and interaction precautions.
- Energy beverages: content and safety.
PMID 21037046 · 2010 · narrative reviewEnergy-beverage content and safety review supports counting all caffeine sources.
- International society of sports nutrition position stand: energy drinks and energy shots.
PMID 36862943 · 2023 · narrative reviewEnergy-drink position stand: caffeine/formulation safety context.
- Safety of herbal supplements: a guide for cardiologists.
PMID 20633025 · 2010 · narrative reviewHerbal cardiovascular safety review; disease and medication precautions.
- Cardiovascular adverse reactions associated with Guarana: is there a causal effect?
PMID 15277107 · 2002 · clinical report / other studyCardiovascular adverse-reaction reports/review; does not quantify causal incidence.
- Acute hemorrhagic myocardial necrosis and sudden death of rats exposed to a combination of ephedrine and caffeine.
PMID 15537744 · 2005 · animal studyRat ephedrine-plus-caffeine myocardial injury/sudden-death experiment; preclinical hazard evidence.
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