Guarana is a Brazilian plant native to the Amazon basin.

Also known as Paullinia cupana, it’s a climbing plant prized for its fruit.

A mature guarana fruit is about the size of a coffee berry. It resembles the human eye, with a red shell encasing a black seed covered by a white aril.

Guarana extract is made by processing the seeds into a powder (1).

Amazonian tribes have used guarana for centuries for its therapeutic properties (2).

It contains an impressive range of stimulants, such as caffeine, theophylline and theobromine. Guarana also boasts antioxidants, such as tannins, saponins and catechins (3).

Today, 70% of guarana produced is used by the beverage industry in soft and energy drinks, while the remaining 30% is turned into powder (1).

Here are 12 benefits of guarana, all supported by science.

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Guarana is loaded with compounds that have antioxidant properties.

These include caffeine, theobromine, tannins, saponins and catechins (3, 4, 5).

In fact, guarana has an antioxidant profile similar to that of green tea (6).

Antioxidants are important because they neutralize potentially harmful molecules called free radicals. These molecules can interact with parts of your cells and cause damage linked to aging, heart disease, cancers and other diseases (7).

Test-tube studies have found that guarana’s antioxidant properties may combat cancer cell growth and reduce heart disease risk and skin aging (8, 9).

Summary Guarana contains caffeine, theobromine, tannins, saponins, catechins and other compounds that have antioxidant properties.

Guarana is best known as an ingredient in popular energy drinks.

It’s an excellent source of caffeine, which helps you maintain focus and mental energy.

In fact, guarana seeds may contain four to six times more caffeine than coffee beans (10).

Caffeine works by blocking the effects of adenosine, a compound that helps your brain relax. It binds to adenosine receptors, preventing them from being activated (11).

A study found that people who took a guarana-containing vitamin supplement felt less fatigued while completing several tests, compared to those who took a placebo (12).

Interestingly, studies also show that guarana can reduce mental fatigue due to cancer treatment, without significant side effects (13, 14, 15).

Summary Guarana is rich in caffeine, which can reduce fatigue and improve focus. Caffeine blocks the effects of adenosine, a compound that makes you feel drowsy and helps your brain relax.

Research has shown that guarana may improve your ability to learn and remember.

One study looked at the effects of different doses of guarana on mood and learning. Participants received either no guarana, 37.5 mg, 75 mg, 150 mg or 300 mg (16).

People who received either 37.5 mg or 75 mg of guarana achieved the highest test scores. Since low doses of guarana provide low doses of caffeine, it’s believed that other compounds in guarana aside from caffeine may be partially responsible (16).

Another study compared guarana to ginseng, another brain-boosting compound.

Although both guarana and ginseng improved memory and test performance, people who received guarana paid more attention to their tasks and completed them faster (17).

Furthermore, animal studies have shown that guarana can improve memory (18, 19).

Summary Low doses of guarana can improve mood, learning and memory. Compounds in guarana, along with caffeine, are responsible for these effects.

It’s estimated that one in three American adults is obese (20).

Obesity is a growing concern, as it has been linked to many chronic diseases, including heart disease, type 2 diabetes and cancer (21).

Interestingly, guarana may have properties that help promote weight loss.

First, guarana is a rich source of caffeine, which may boost your metabolism by 3–11% over 12 hours. A faster metabolism means your body burns more calories at rest (22).

What’s more, test-tube studies have found that guarana may suppress genes that aid fat cell production and promote genes that slow it down (23, 24).

However, guarana’s effects on fat cell production in humans remain unclear.

Summary Guarana contains caffeine, which may aid weight loss by boosting metabolism. It has also been found to suppress genes that aid fat cell production and promote genes that slow it down. However, more human-based studies are needed.

Guarana has been used for centuries as a natural stomach tonic to treat digestive problems like chronic diarrhea and constipation (1).

It may have anti-diarrhea properties because it’s rich in tannins, or plant-based antioxidants.

Tannins are known for their astringency, which means they can bind and contract tissue. This allows tannins to waterproof the walls of your digestive tract, restricting how much water is secreted into your bowels (25).

On the other hand, guarana is rich in caffeine, which may act as a natural laxative.

Caffeine stimulates peristalsis, a process that activates contractions in the muscles of your intestines and colon. This may relieve constipation by pushing contents to the rectum (26).

Low doses of guarana do not provide much caffeine, so they are more likely to have an anti-diarrhea effect. High doses provide more caffeine and may have laxative effects.

Summary The tannins in guarana may relieve diarrhea by preventing water loss. Meanwhile, the caffeine in guarana may relieve constipation by stimulating contractions in your intestines and colon that push contents toward the rectum.

Heart disease is responsible for one in four deaths in America (27).

Guarana may reduce the risk of heart disease in two ways.

First, the antioxidants in guarana appear to aid blood flow and may prevent blood clots (28).

Second, studies have shown that guarana may decrease the oxidation of “bad” LDL cholesterol. Oxidized LDL cholesterol can contribute to plaque build-up in your arteries.

In fact, adults who consume guarana may have up to 27% less oxidized LDL than adults of a similar age who don’t eat this fruit (29).

However, most research on the connection between heart health and guarana comes from test-tube studies. More human-based studies are needed before recommendations can be made.

Summary Guarana may aid heart health by improving blood flow and preventing blood clots. It can also decrease the oxidation of “bad” LDL cholesterol.

Historically, guarana was used by Amazonian tribes as a pain reliever.

The pain-relieving properties of guarana are due to its high caffeine content.

Caffeine plays a role in pain management, as it binds and blocks adenosine receptors.

Two of these receptors — A1 and A2a — are involved in stimulating feelings of pain (30).

When caffeine binds to these receptors, it can reduce sensations of pain.

This is one reason why caffeine is commonly found in many over-the-counter pain relief medications. Studies have shown it can significantly enhance their effects (31).

Summary The caffeine in guarana may provide pain relief by blocking adenosine receptors, which are involved in stimulating feelings of pain.

Due to its strong antioxidant and antimicrobial properties, guarana is popular in the cosmetics industry as an ingredient in anti-aging creams, lotions, soaps and hair products.

Moreover, its caffeine content aids blood flow to the skin (32).

Test-tube studies have shown that the antioxidants in guarana may significantly reduce age-related skin damage (9).

What’s more, animal studies indicate that guarana-containing cosmetics may reduce sagging in your cheeks, improve skin tightness and minimize wrinkles around your eyes (33).

Summary Guarana has antioxidant and antimicrobial properties, making it a common additive in cosmetic products. It may aid blood flow to your skin, reduce damage linked to aging and minimize undesirable features, such as saggy skin and wrinkles.

Cancer is a disease characterized by the uncontrolled growth of cells.

Animal and test-tube studies suggest that guarana may protect against DNA damage, suppress cancer cell growth and even trigger cancer cell death (34, 35, 36).

One study in mice found that those fed guarana had 58% fewer cancer cells and nearly a five-fold increase in cancer cell death, compared to mice that did not receive guarana (36).

Another test-tube study found that guarana suppressed the growth of cancer cells in the colon, as well as stimulated their death (37).

Scientists believe that the potential anti-cancer properties of guarana stem from its content of xanthines, which are compounds that are similar to caffeine and theobromine.

That said, though the results of test-tube and animal studies are promising, more human-based research is needed.

Summary Animal and test-tube studies have found that guarana may have anti-cancer properties. However, human-based research is required before recommending guarana for treatment.

Guarana contains many compounds that may inhibit or kill harmful bacteria.

One of these bacteria is Escherichia coli (E. coli), which lives in the intestines of humans and animals.

Most E. coli bacteria are harmless, but some can cause diarrhea or illness (38, 39).

Studies have also found that guarana can suppress the growth of Streptococcus mutans (S. mutans), a bacteria that can cause dental plaques and tooth decay (40, 41).

It’s believed that the combination of caffeine and plant-based compounds like catechins or tannins is responsible for guarana’s antibacterial effects (38, 42).

Summary Guarana contains compounds that may inhibit or kill harmful bacteria, such as E. coli and Streptococcus mutans.

It’s common for eyesight to progressively worsen with age.

Things like sunlight, poor diet and certain lifestyle choices like smoking can wear down your eyes over time and increase your risk of eye-related disorders (43).

Guarana contains compounds that fight oxidative stress, a major risk factor for age-related eye disorders like macular degeneration, cataracts and glaucoma (44).

One study found that people who consumed guarana regularly had better self-reported vision than people who consumed it sparingly or not at all (45).

In the same study, scientists performed test-tube experiments to discover if guarana could protect eye cells against compounds that create oxidative stress. Guarana significantly reduced the amount of DNA damage and eye cell death, compared to a placebo (45).

That said, there is limited research in the area of guarana and age-related eye disorders. More human-based studies are needed before recommendations can be made.

Summary Test-tube studies have found that guarana may combat oxidative stress, which is linked to age-related eye disorders. However, this area of research is limited, so more human-based studies are needed before providing recommendations.

Guarana has an excellent safety profile and is widely available.

Research shows that guarana has low toxicity in low-to-moderate doses (19, 46, 47).

In high doses, guarana may cause side effects similar to those of excessive caffeine intake, including (48, 49):

  • Heart palpitations
  • Insomnia
  • Headaches
  • Seizures
  • Anxiety
  • Nervousness
  • Upset stomach
  • Shakiness

It’s worth noting that caffeine can be addictive and lead to dependency in high doses (50).

Pregnant women should avoid or limit guarana intake, as caffeine can cross the placenta. Too much caffeine may cause growth abnormalities in your child or increase the risk of miscarriage (51).

Although guarana has no recommended dosage, most human-based research has found that doses as low as 50–75 mg can provide the health benefits linked to guarana (16, 17).

Summary Guarana appears to be safe and is widely available. In high doses, it may have similar side effects to those of excessive caffeine intake.

Guarana is a popular ingredient in many energy and soft drinks.

It has been used by Amazonian tribes for its therapeutic effects for centuries.

Guarana is commonly touted for its ability to reduce fatigue, boost energy and aid learning and memory. It has also been linked to better heart health, weight loss, pain relief, healthier skin, lower cancer risk and a decreased risk of age-related eye diseases.

It’s widely available as a supplement and can be easily added to your diet.

Most research shows that doses between 50–75 mg of guarana are sufficient to provide you with health benefits, though there is no official dosage recommendation.

Whether you want to boost your energy levels or simply improve your overall health, guarana may be worth a try.