Guarana and Medications: Interactions to Know Before Taking

Guarana contains caffeine, and it is that caffeine that lies behind most of the possible interactions with medicines. There are no clinical studies that test guarana directly with specific medicines, so what is known comes mainly from what is known about caffeine. In practice: if you take medicines, especially for the heart, for the thyroid, anticoagulants or other stimulants, speak to your doctor or pharmacist before starting — and also tell them about the caffeine you already consume in coffee, tea or soft drinks.

This page explains why the caffeine dose is the central point, which groups of medicines are worth paying attention to, what the label of the Energy Gummies with Guarana says, and which signs justify stopping and seeking help.

Why does guarana matter in drug interactions?

Guarana (Paullinia cupana) is a plant whose seeds contain caffeine, as well as other compounds such as tannins and saponins. It is caffeine that explains most of the stimulant effects and, consequently, most of the predictable interactions. Caffeine acts by blocking adenosine receptors and increasing calcium release, which can cause arrhythmias and myocardial stress — mechanisms described in a systematic review on energy drinks, which associates chronic consumption with QTc interval prolongation, atrial and ventricular arrhythmias and hypertensive episodes, even in young and healthy people ¹.

It is important to note that this review looked at energy drinks, which combine caffeine with taurine and other compounds, and not guarana on its own. It serves as a sign that caffeine at high doses is not innocuous, but it does not allow the conclusion that guarana in gummies has the same profile. What can be said safely is that the amount of caffeine ingested is the factor that weighs most.

How much caffeine does guarana have? The problem of variability

The amount of caffeine in guarana varies greatly between products, forms and doses. In a double-blind clinical trial with 11 cyclists and endurance practitioners, a dose of 500 mg of guarana extract provided 130 mg of caffeine ². In another trial, also double-blind and crossover, 500 mg of guarana likewise contained 130 mg of caffeine ³. In a meta-analysis of 8 placebo-controlled studies, which brought together 328 participants, guarana doses ranged from 37.5 mg to 500 mg, with a reported caffeine content between 4.3 mg and 100 mg ⁴.

In other words: the same amount of guarana powder can give very different amounts of caffeine. That is why, to assess an interaction, it is not enough to know that you take guarana — you need to know how much caffeine is actually entering the body. The Energy Gummies with Guarana provide 200 mg of guarana extract per 2-gummy serving, of which 44 mg of caffeine, according to the product label. Note that the trials used 500 mg of guarana (130 mg of caffeine); the gummies provide 200 mg of extract and 44 mg of caffeine per serving. Study doses are not dosing instructions.

Which medicines deserve most attention?

The specific evidence for guarana is scarce; what exists is knowledge about caffeine. With that caveat, these are the groups in which it is worth thinking twice.

Stimulants and medicines for ADHD

Combining caffeine with stimulants such as amphetamines or methylphenidate can excessively increase stimulation, with a risk of palpitations, anxiety and a rise in blood pressure. This is the combination that requires most caution and should be discussed with the prescribing doctor.

Anticoagulants

Caffeine may, in theory, affect clotting, but the data are inconsistent. If you take warfarin or another anticoagulant, the most prudent approach is to keep your caffeine intake stable and inform your doctor, so that any change is made in a controlled way.

Quinolone antibiotics

Antibiotics such as ciprofloxacin can reduce the metabolism of caffeine, increasing its effects and the risk of nervousness, palpitations and insomnia. During treatment with an antibiotic of this group, it may make sense to reduce or avoid guarana.

Thyroid medicines

Caffeine can interfere with the absorption of levothyroxine. The usual recommendation is to take the medicine with water and wait some time before consuming caffeine — a general guideline for caffeine, not specific to guarana.

Sedatives and anxiolytics

Caffeine can counteract the sedative effect of benzodiazepines and other medicines for sleep or calming. It is not a dangerous interaction, but it can make the medicine less effective and be frustrating for those who need it.

Practical comparison: where the risk lies

Group of medicines	Type of possible interaction	Suggested approach
Stimulants (amphetamines, methylphenidate)	Excessive stimulation, palpitations, anxiety, hypertension	Avoid or discuss with the doctor
Anticoagulants (warfarin)	Effect on clotting, inconsistent data	Keep intake stable and inform the doctor
Quinolone antibiotics (ciprofloxacin)	Less caffeine metabolism, more stimulant effects	Reduce or avoid during treatment
Levothyroxine	Possible interference with absorption	Take with water and space out caffeine
Benzodiazepines and sedatives	Reduced sedative effect	Monitor the effectiveness of the medicine

This table summarises scenarios described for caffeine. It does not replace the assessment of a professional who knows your case.

What the label of the Energy Gummies with Guarana says

The Energy Gummies with Guarana state on the label 200 mg of guarana extract per 2-gummy serving, of which 44 mg of caffeine, as well as 200 mg of L-theanine, 100 mg of L-tyrosine, 1.4 mg of vitamin B6 (100% NRV), 10 µg of vitamin B12 (400% NRV) and 40 mg of vitamin C (50% NRV). The directions for use state to chew 2 gummies per day, preferably after a meal, without exceeding the recommended daily dose.

The product warnings are clear: contains caffeine (44 mg per daily dose); not recommended for children, pregnant or breastfeeding women; contains polyols, and excessive consumption may have laxative effects; in case of illness or taking medicines, you should consult a health professional before consuming. This last warning is precisely the one that applies to this page.

Keep the gummies out of reach of younger children: their appearance and sweet taste may lead them to be mistaken for sweets and consumed in quantity. As each gummy contains caffeine, eating several at once can give a higher dose than planned. If you are managing your weight or have diabetes, also note that the gummies contain polyols (maltitol), whose excessive consumption may have laxative effects, and that frequent chewing of sugary gummies requires attention to oral hygiene.

Vitamin B6 and vitamin B12 contribute to normal energy-yielding metabolism and vitamin C contributes to the normal function of the immune system, as per the authorised claims in Regulation (EU) No 432/2012 ⁵. There are no authorised health claims in the EU for guarana as a botanical ⁵.

Does guarana do anything beyond caffeine?

It is a legitimate question and the honest answer is: it is not known for certain. In human trials, guarana has been studied mainly for its caffeine content. In a meta-analysis of 8 placebo-controlled studies (328 participants), the average effect of guarana on various cognitive measures was less than trivial (Hedge's g = 0.076), although a small effect appeared on response time (g = 0.202) that was not seen in accuracy ⁴. In a trial with 28 healthy young adults (18–24 years), a single dose of 75 mg of guarana extract improved performance on attention tasks, but with some evidence of reduced accuracy ⁶.

In another trial with 20 participants, 500 mg of guarana (130 mg of caffeine) did not alter cognitive performance or heart rate variability compared with placebo or with 100 mg of caffeine alone ³. These results do not clarify whether the other compounds in guarana have pharmacological effects relevant to interactions — they only show that, in the studies carried out, the picture is modest and sometimes inconsistent. For a more detailed view of what science shows about the effects of guarana, see the article on how guarana works.

Who should speak to a professional before taking it

Some groups should seek guidance before using guarana, even at moderate doses:

• People with heart problems, such as arrhythmias, uncontrolled hypertension or coronary artery disease.
• Pregnant and breastfeeding women — caffeine crosses the placenta and passes into breast milk. There is a dedicated article on guarana during pregnancy.
• Children and adolescents, who are more sensitive to caffeine and for whom there is not enough data.
• People with anxiety or insomnia, because caffeine can worsen these symptoms.
• Anyone taking any medicine on a regular basis — the right question is not "can I take guarana?", but "can I take guarana with what I already take?".

If you want to understand the safety limits better and who should avoid it, see the article does guarana have side effects? What the evidence says.

When to stop and seek help

The most frequent effects of guarana are those of caffeine: nervousness, agitation, difficulty falling asleep, increased heart rate, headaches and, in some people, gastrointestinal discomfort. They are generally mild and disappear when the body metabolises the caffeine.

If you feel any of these mild symptoms, drink water, rest and avoid more caffeine until they pass. You do not need to alarm yourself: they are normal reactions to a stimulant substance and usually disappear on their own.

There are, however, signs that should not be ignored: chest pain, irregular heartbeat, shortness of breath, fainting or near-fainting, confusion or persistent vomiting. If any of these symptoms appear, stop taking it and seek medical help. These signs may indicate a more serious adverse reaction, especially in those who have an underlying heart condition or take other stimulants.

What is still not known

There are no robust clinical studies on specific interactions between guarana and medicines. Most of what is known comes from extrapolations from caffeine, and even there the studies are often small. It is not known whether the other compounds in guarana — tannins, saponins — can interact with medicines, nor whether the slower release of caffeine from guarana changes the risk. The absence of information is not proof of safety: if your medicine does not appear on this page, that does not mean the combination is harmless.

If you want to go deeper into the dose and how to read the label, see the guide on guarana daily dose. If your doubt is about the format, there is a comparison between guarana gummies or tablets. And if you are looking for general information about the ingredient, start with the guarana page. In any case, for a personalised answer about your medication, the pharmacist or doctor is the best resource.

Frequently asked questions

Does guarana interact with medicines?

Guarana contains caffeine, and it is that caffeine that lies behind the possible interactions. There are no clinical studies that test guarana directly with specific medicines, so what is known comes from knowledge about caffeine. If you take medicines on a regular basis, speak to your doctor or pharmacist before starting.

Can I take guarana if I take anticoagulants?

The data on caffeine and clotting are inconsistent: some studies suggest a slight increase in bleeding risk, others find no effect. The most prudent approach is to keep your caffeine intake stable and inform your doctor, so that any change is made in a controlled way.

Does guarana interfere with antibiotics?

Some antibiotics of the quinolone class, such as ciprofloxacin, can reduce the metabolism of caffeine, increasing its effects and the risk of nervousness, palpitations and insomnia. During treatment with an antibiotic of this group, it may make sense to reduce or avoid guarana.

How much caffeine does guarana have?

It varies greatly. In a meta-analysis of 8 studies, guarana doses ranged from 37.5 mg to 500 mg, with a reported caffeine content between 4.3 mg and 100 mg. The Energy Gummies with Guarana provide 200 mg of guarana extract per 2-gummy serving, of which 44 mg of caffeine, according to the label.

Who should avoid guarana?

People with heart problems, pregnant or breastfeeding women, children and adolescents, and those with anxiety or insomnia should take extra care and speak to a health professional first. The label of the Energy Gummies with Guarana states that they are not recommended for children, pregnant or breastfeeding women.

Which symptoms mean you should stop taking guarana?

Chest pain, irregular heartbeat, shortness of breath, fainting or near-fainting, confusion or persistent vomiting. If any of these symptoms appear, stop taking it and seek medical help. Nervousness, insomnia or mild headaches are more common and usually pass when the body metabolises the caffeine.