What is Guarana?
Guarana (Paullinia cupana) is a species of climbing plant native to the Amazon regions known for its stimulant and medicinal properties. It has been used for centuries by indigenous peoples of the Amazon for its diuretic properties, therapeutic effects against headaches, fever, and cramps, and aphrodisiac effects .
With a taste that is described as slightly bitter, astringent, and acidic, guarana powder dissolved in water is considered by indigenous peoples as an elixir that promotes long life .
Guarana is still primarily produced in the Brazilian states of Amazonas and Bahia. Approximately 70% of the production is used by soft and energy drink industries, while the other 30% becomes guarana powder for consumption directly or dilution in water, or as raw material for pharmaceutical and cosmetic industries .
Guarana seeds contain high amounts of methylxanthines and tannins, as well as saponins, starches, polysaccharides, pigments, fats, and choline. The methylxanthines, which include caffeine, theophylline, and theobromine, are found in the organs and seeds of the plant. Guarana also contains flavonoid and purine alkaloids [4, 5].
Other phenolic compounds found in guarana seeds include epicatechin, catechin, and ent-epicatechin .
The caffeine and catechins in guarana prevent the arteries from hardening (atherosclerosis) by reducing oxidative damage and lowering LDL, the “bad” cholesterol .
Caffeine and a flavonoid (catechin or epicatechin) in guarana in the presence of potassium act as mutagens and cause the death of harmful bacteria (E. coli, S. mutans, and salmonella) by having destructive effects on their DNA .
Health Benefits of Guarana
1) Guarana Assists in Weight Loss
Guarana is classified as a metabolic stimulant, which means it helps consumers burn more calories throughout the day because of its caffeine contents .
Overall, it increases fat (lipid) metabolism, enhances weight loss, and increases the amount of energy used for basic metabolic function, such as breathing and digestion .
In an 8-week study (DB-RCT) of 67 participants, taking a herbal supplement containing Ma Huang and guarana resulted in significant weight loss and reductions in hip circumference compared to placebo .
In addition to burning fat, guarana may prevent the generation of fat altogether by decreasing the production of genes that contribute to the fat generation and increasing the production of genes that prevent it .
2) Guarana Improves Mental Health
In another study (DB-RCT) of 20 subjects, the participants either consumed multivitamins with or without guarana and a placebo. The participants who consumed multivitamins with guarana had an increased benefit of mood and cognitive performance .
Guarana’s effect on mental health and performance may be attributable to a relatively high content of saponins and tannins that work along with caffeine .
3) Guarana Has Anti-cancer Effects
In mouse models, guarana inhibited, delayed, or reversed the growth and formation of cancers and metastases, reduced tumor cell formation, increased tumor cell death in melanoma colonies, and reduced the incidence of visible liver tumors [13, 13, 16].
4) Guarana May Boost Energy and Reduce Fatigue
Guarana has been used as a stimulant for centuries by indigenous peoples of the Amazon. In a cross-sectional study of 43 breast cancer patients, guarana improved fatigue while maintaining the quality of sleep. It had negligent effects on anxiety and depression regularly associated with caffeine .
Since fatigue is one of the most common symptoms of multiple sclerosis (MS), patients may use guarana as a source of caffeine to combat it. By stimulating the brain, it decreases fatigue but might worsen other symptoms of multiple sclerosis .
Mice that ingested a low dosage (0.3 mg/mL) of guarana had increased physical ability when subjected to forced swimming. However, similar effects were not observed with 3.0 mg/mL of guarana or 0.1 mg/mL caffeine. This suggests benefits are exclusive to low doses of guarana and not based solely on caffeine .
5) Guarana Is an Antioxidant
Guarana protects against cadmium-induced free radical damage, by reducing changes in Leydig cells (critical to the male reproductive system), and inflammatory responses in animals exposed to the metal [5, 20].
In animals treated with guarana and exposed to cadmium, this resulted in increased relative testosterone levels and an increase in the size of seminiferous tubules, indicating elevated sperm formation [5, 20].
6) Guarana Benefits Skin
Guarana is often used in products that treat cellulitis based on its high content of alkaloids, particularly caffeine. Anti-aging creams, cleansing lotions and soaps, shampoos, and conditioners also utilize guarana as an active ingredient .
On pigskin and in 43 human male subjects, 6 weeks of applying a formula containing guarana, creatine, and glycerol helped with skin quality. It increased collagen production and reduced cheek sagging, crow’s feet wrinkles, and under-eye wrinkles .
Seed extracts of guarana possess strong antimicrobial and antioxidant properties, making them a useful additive in cosmetics .
7) Guarana Is Antibacterial
E. coli bacteria cells are a normal part of gut flora. However, certain strains of E. coli grow rapidly in inflammatory environments and produce alpha-hemolysin, a toxin that causes leaky gut, inflammation, and bleeding. Guarana extract induced cell death in E. coli [8, 22].
8) Guarana Contributes to Heart Health & Acts as a Blood Thinner
Guarana extracts can also protect the heart. This effect is derived from its ability to prevent blood cell clumping (platelet aggregation) in both human and rabbit blood .
In a cross-sectional study involving 42 healthy elderly patients, guarana prevented hardening of the arteries. It also had antioxidant and protective effects against fat accumulation and formation .
9) Guarana Helps with Digestion
During a review of 637 elderly subjects residing in the Amazon Riverine region of Brazil, a prevalence of metabolic disorders such as obesity, hypertension, and metabolic syndrome, was decreased in populations that reported regular or daily guarana ingestion .
Guara, therefore, offers a protective effect from gut problems associated with obesity, gut bleeding associated with hypertension, and irritable bowel syndrome (IBS), which is positively linked to metabolic syndrome [27, 28, 29].
Limitations and Caveats
There are not a lot of human trials available. Since most of the evidence comes from animal studies, take caution before using guarana extensively for its purported health benefits.
Little is known about the other constituents of guarana because its effects are so often assumed to be attributed solely to caffeine. It is difficult to assess to what degree these constituents contribute to the full effects of guarana.
Herbal extracts have complex dose-effect relationships on behavior and physiology, and it is possible that artificially higher doses of caffeine are masking the effects of the other active ingredients. In an untampered formula, guarana’s constituents may act more synergistically .
Little specific research associating guarana as an aphrodisiac has been performed. It has been marketed as an aphrodisiac by soda manufacturers to help launch guarana soda in industrial nations. Unless combined with other active ingredients, its effects as an aphrodisiac are negligible .
Most cited negative effects of guarana are a direct result of the use of energy drinks with guarana extract. Consumers experience negative symptoms similar to caffeine overdose or those associated with sugar and high fructose corn syrup [31, 32].
Although not widely or specifically studied, guarana should be expected to exhibit the same range of adverse effects as those associated with caffeine .
In one case study, a 44-year-old man with no significant health problems had symptoms of caffeine toxicity after ingesting guarana extract. He experienced nausea, vomiting, anxiety, and heart palpitations [34, 35].
Human nerve cells had increased cell death in the presence of a combination of caffeine, taurine, and guarana .
Tannins in guarana may cause inflammation .
In a study (DB-RCT) involving 27 human subjects, no subjects reported any adverse effect on mood or anxiety after taking guarana extract 360 mg 3 times daily for 5 days .
The extract of guarana seeds shows low toxicity, evidenced by an unchanged average lifespan in mice subjected to long-term ingestion, and is safe to consume for different pharmacological activities [19, 5].
Sources of Guarana
Commercially available products containing guarana come in many forms. Confections such as chocolate products, fruit-juice-based drinks, “energy drinks,” dietary supplements, and weight loss products are a few examples. The main commercial use of guarana in Brazil is a carbonated soft drink .
In guarana extract, the caffeine concentration can be double or triple that found in the seed. Traditionally, guarana extract is prepared in Brazil using hot water or hydro-alcoholic solutions as a solvent. One of the uses of concentrate extracts is to produce guarana-based energy tonics. Guarana extract is commercially available as a pill or powder .
Guarana sodas in the form of energy drinks mostly contain caffeine, taurine, L-carnitine, carbohydrates, glucuronolactone, vitamins, and occasional herbal supplements such as ginseng. Additives such as yerba mate, cocoa, and kola nut may increase the caffeine content of such sodas .
Guarana vs. Caffeine
Because guarana contains a naturally high concentration of caffeine, guarana grants many of the same effects as a single dose of caffeine. However, guarana has other main ingredients which may act together to offer health benefits that can be overlooked .
Amiodarone, a drug used to treat certain types of irregular heartbeat such as persistent ventricular fibrillation/tachycardia, was given to a group of rats along with guarana extract. These rats were shown to have decreased levels of amiodarone compared to those who did not take it with guarana extract, indicating that guarana decreases the bioavailability of amiodarone in rats .
Extracts of Panax ginseng, which are often sold in combination with guarana, contain similar potentially active components. In a study (DB-PCT) of 28 healthy participants, a combination of guarana and ginseng significantly improved their performance on math problems. However, there is no evidence of synergism between the 2 supplements .
YDG is an herbal supplement composed of yerba mate, guarana, and damiana. In a group of 58 normal-to-slightly-overweight women, YDG consumption led to a decrease in food intake. Subjects that completed a 28-day trial of YDG also ate less at meals and snacked less frequently .
Catuama is a preparation consisting of guarana, ginger, Muira puama (potency wood), and Trichilia catigua. It has a potent relaxing effect on blood vessels in different animal species. Catuama reverted heartbeat irregularities in isolated rabbit hearts and prevented its reintroduction, but guarana is thought to have no effect and the ingredients are not believed to work synergistically .
Consumers of guarana extracts experienced increased physical capacity and vigor, helping them get through the day or strenuous activity without a crash. They reported improved mood and heightened contentment.
In clinical subjects, there were no reported adverse psychological effects from guarana extracts, as there may be experienced with other energy supplements such as caffeine pills or energy drinks.