Guarana: methods of use, precautions and contraindications

Guarana (Paullinia cupana) is appreciated for its stimulating effects on energy and concentration, but its use requires certain precautions. In powder, extract or dietary supplement form, it should be taken in moderation to avoid the undesirable effects associated with its high caffeine content. What are the correct doses? What contraindications should I be aware of? Find out how to use guarana safely and optimally.

The effects of guarana on the body: antioxidant, digestive and protective

Guarana hydroalcoholic extract reduces fibroblast mortality. It also reduces pro-oxidant effects, such as lipid peroxidation, DNA damage and oxidative stress. These effects are usually caused by nitric oxide (NO). Guarana contains a high concentration of polyphenols. This composition gives it significant antioxidant potential. As a result, it offers protection against cadmium toxicity. It also stimulates spermatogenesis.

Guarana also reduces the volume of gastric secretion and total acidity, reducing ethanol-induced gastric ulceration. Its gastroprotective effect differs from that of caffeine alone, suggesting other active components.

Research has demonstrated guarana’s antibacterial activity against a number of pathogens. Although the specific impact of guarana on constipation remains to be established, its high caffeine content could stimulate intestinal muscle contractions. What’s more, its fibre content could help combat constipation. However, constipation is a complex symptom, often requiring medical consultation to determine the cause.

The dietician-nutritionist advises consuming between 2 and 4 g of Guarana powder a day, incorporating it into drinks, juices, smoothies or dairy products. It is important to avoid excessive doses to prevent undesirable effects. In the event of constipation, it is advisable to drink plenty of water and eat a diet rich in fibre.

With regard to the liver, studies on guarana and caffeine show contradictory effects. These studies, based on animal models, do not offer any definitive conclusions about the benefits of guarana on the liver. Excessive caffeine consumption can cause liver problems. It is therefore advisable to consume guarana in moderation and to favour a balanced diet for liver health, consulting a health professional in the event of liver problems.

Are there any precautions to be taken when taking Guarana?

Guarana is a beneficial plant. However, its use requires precautions. Consuming guarana can be risky for some people. This applies in particular to pregnant or breast-feeding women. People with high blood pressure or heart problems should also be cautious. Similarly, those suffering from anxiety disorders should take care.

Contraindications

• Due to its high caffeine content, guarana is not recommended for people with cardiovascular disorders (hypertension, tachycardia, arrhythmia), insomnia, anxiety disorders, progressive gastric or duodenal ulcers or hyperthyroidism.
• Not recommended for people with a known allergy to Sapindaceae.
• According to the EMA, guarana is not recommended for pregnant (abortifacient) or breast-feeding women, or for children and adolescents under the age of 18, due to the presence of alkaloids in the plant.

Side effects

• Given the possible dependence associated with prolonged consumption of guarana and caffeine (possible cumulative effect with other sources of this molecule), withdrawal may lead to headaches, irritability, agitation and anxiety, or, on the contrary, drowsiness and confusion.
• Tachycardia, irritability, headaches, agitation, gastrointestinal disorders due to the presence of caffeine

Precautions for use

• Use with caution: If you consume a lot of coffee, tea, yerba mate, kola nuts, or other caffeine-rich products. Be aware of the cumulative effect of caffeine.
• People undergoing treatment with amiodarone, MAOIs or sympathicomimetics (with the exception of ephedrine) should be vigilant because of possible interactions.
• Those suffering from glaucoma should also exercise caution.
• Avoid taking guarana before going to bed. It can disturb your sleep and reduce the effectiveness of sedatives.
• Abruptly stopping your usual caffeine intake can cause withdrawal symptoms. These symptoms include fatigue, headaches and irritability. These symptoms tend to diminish gradually over the week following cessation.

Drug interactions

• Do not combine with ephedrine-based preparations.
• The caffeine in guarana can interfere with many drugs. This list includes benzodiazepines, theophylline, bronchodilators, diabetes treatments, diuretics, lithium, cimetidine, antacids, clozapine, MAO inhibitors, alendronate, anticoagulants, platelet anti-aggregants and nicotine. In the event of regular or intensive use of guarana with these substances, it is essential to consult a doctor and undergo medical supervision.
• Pharmacokinetic interactions: CYP1A2 substrate
• Pharmacodynamic interactions: Addition of effect with antihypertensives, analgesics, triptans, theophylline (caffeine)
• Reduced effect of sedatives, anxiolytics and antidepressants (caffeine)
• Anti-hypertensives

How should Guarana be taken and at what dosage?

Guarana’s main active substance is caffeine, with the seeds containing between 2.5% and 7%. This concentration is 2 to 3.5 times higher than in coffee beans. A minimum dose of 60 mg of caffeine is generally required for a noticeable effect that may last a few hours. However, heavy caffeine consumers may need higher doses (200 mg or more) due to habituation.

The caffeine content of commercial guarana preparations varies widely, sometimes reaching over 250 mg per dose. It’s crucial to read labels carefully. By way of comparison, 1 cup of coffee (250 ml) contains between 75 mg and 180 mg of caffeine.

In 2003, experts from Health Canada’s Food Directorate concluded that a daily intake of 400 mg to 450 mg of caffeine poses no major health risk. However, pregnant and breast-feeding women should limit their intake to a maximum of 300 mg of caffeine a day (equivalent to around 2 cups of coffee).

• As a dietary supplement, in the form of standardised fresh plant extract, dry extract, powder or capsules.
• Standardised fresh plant fluid extract: 5 to 10 ml per day in a glass of water.
• Honey glycerine fluid extract: 5 ml 1 to 2 times a day in water.
• Infusion: 0.5 g to 1 g of powdered guarana or a few seeds per 200 ml of water for 5 to 10 minutes, to be taken 1 to 2 times a day.

There are also many guarana-based energy drinks, rich in caffeine and often containing other substances.

Guarana as a magistral preparation of standardised extracts in liquid form (EPS)

Guarana can be used in the form of standardised liquid extracts (EPS), for faster, more effective absorption of the active ingredients. In this article, we will explore the advantages of this method of preparing guarana as a magistral preparation.

• In combination with ginseng: For physical and mental asthenia and low blood pressure.
• In combination with liquorice: For exhaustion syndrome or low blood pressure.
• In combination with turmeric: In the treatment of overweight and obesity, metabolic action and basal metabolism.
• In combination with caralluma: To help with weight loss, for its satiety-enhancing effect.
• In combination with Rhodiola: To combat intellectual overwork, mental exhaustion and mood disorders.
• In association with oats: To combat cognitive disorders and mental fatigue in the context of a weak thyroid or proven hypothyroidism.