What Is Guayusa Tea?

Guayusa tea is a caffeinated herbal beverage commonly consumed in South America, particularly in Ecuador. The holly tree (Ilex guayusa) used for making the tea is native to the Amazon rainforest.

The extract of guayusa contains caffeine and theobromine. Theobromine, a substance also found in cocoa, is thought to offer mood-enhancing effects.

The leaves of guayusa have stimulant and antioxidant properties. Due to such properties, guayusa tea can potentially serve as an energy drink alternative.

Uses of Guayusa

Some health benefits of guayusa tea include alertness and antioxidant and anti-inflammatory properties.

Alertness

The stimulating effect of guayusa tea that contributes to alertness is due to the caffeine content. Furthermore, the caffeine content of guayusa tea was similar to that of green and black tea.

Researchers conducted a randomized, double-blind clinical trial of guayasa leaf extract. It contained 12 subjects assigned male at birth, 21 to 34 years old. Compared with the green coffee extract and synthetic caffeine, guayusa leaf extract was less stimulating to epinephrine release. Further studies are needed to determine the effect of the different doses of each caffeine source.

Antioxidant Activity

Antioxidants are compounds that help prevent cell damage from oxidation in the body. An in vitro (test-tube) study has shown that guayusa tea extracts protected cells. However, human clinical trials are needed to confirm the antioxidant activity of guayusa.  

Other antioxidants found in the leaves of guayusa include catechin, epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate (EGCG), chlorogenic acid, isochlorogenic acid, and neochlorogenic acid.

Anti-inflammatory Activity

Some preliminary test-tube research suggests that guayusa may help protect against inflammation by reducing nitric oxide production.

Nitric oxide (NO) is responsible for widening small blood vessels. This increases the entry of pro-inflammatory substances into body tissues. Additionally, large amounts of NO can react with oxygen to form highly reactive and destructive nitrogen species (e.g., peroxynitrite), which act as damaging free radicals.

Researchers conducted an in vitro (test-tube) study using a macrophage cell line from mice. An extract of guayusa scavenged NO and reduced its production. Since this was a test-tube study done on an animal cell line, it's unclear if the results can be applied to humans. Further clinical trials conducted in humans are needed to confirm the anti-inflammatory activity of guayusa.

What Are the Side Effects of Guayusa?

Your provider may suggest guayusa for certain reasons. However, consuming an herb like guayusa may have potential side effects. These side effects may be common or severe. 

Researchers who investigated guayusa reported it seems to have no greater risk to human health than existing teas, like green tea or yerba mate.

Common Side Effects

Because guayusa tea contains caffeine, consuming too much caffeine can cause the following:

• Anxiety
• Dehydration
• Dizziness
• Fast heart rate
• Headaches
• Insomnia
• Restlessness and shakiness

Guayusa tea is widely advertised for its energizing and calming effect, with the latter effect proposed to be due to the L-theanine (a type of amino acid) component. L-theanine acts as a relaxant that counteracts the stimulant effect of caffeine, thereby preventing that jittery feeling you get from coffee.

While green tea is known to contain L-theanine, whether or not guayusa tea contains L-theanine remains unclear due to the conflicting reports from several studies. Further research is needed to establish a scientific basis for the broad health claims regarding the presence of L-theanine in guayusa.

Severe Side Effects

One study analyzing the safety of guayusa consumption in Ecuador revealed the following:

• No hospital presentations,
• No product safety notifications, and
• No disease register records of guayusa-related illness.

Precautions

As guayusa tea contains caffeine, it should be used cautiously in the following cases:

• Anxiety
• Arrhythmia
  
• Children and adolescents
• GERD or ulcers
• High blood pressure
  
• Migraines or other chronic headaches
• Pregnant and breastfeeding
• Sleep disorders
  
• Taking certain medications or supplements, like other stimulants, certain antibiotics, asthma medications, and heart medications.

Please check with your pharmacist or healthcare provider if there are any interactions between caffeine and the medications and supplements you take.

Dosage: How Much Guayusa Should I Take?

The dose of guayusa as a dietary supplement is unclear due to the lack of clinical trials evaluating guayusa in supplement form.

However, the caffeine concentration was reported to be 19.08 ± 0.31 milligrams (mg) per one gram (g) of fresh guayusa leaves. This means that two grams or one teaspoon (tsp) of guayusa tea leaves would yield about 38 milligrams of caffeine. 

What Happens If I Take Too Much Guayusa?

While no severe side effects have been noted with guayusa consumption, consuming too much guayusa can cause hyperactivity and difficulty sleeping. This is mainly due to its caffeine content.

For healthy adults, moderate chronic intakes of caffeine up to 400 milligrams (mg) per day are not associated with side effects on heart health.

However, according to the American College of Obstetricians and Gynecologists, pregnant people are recommended to restrict their caffeine intake to less than 200 milligrams per day.

Safe levels of caffeine consumption have not been established in children and adolescents.

Interactions

Regular teas can taste bitter because they contain tannins, which can block iron absorption. On the other hand, while guayusa does not have a bitter taste it does contain tannins. Guayusa tannins may interfere with iron absorption.

The caffeine in guayasa may impact other medications or supplements. For example, other stimulants, certain antibiotics, asthma medications, and heart medications.

It is essential to carefully read a supplement's ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

How to Store Guayusa

Guayusa supplements should be stored in a cool and dry place. Discard as indicated on the packaging.

The dried leaves of guayusa should be stored in an airtight container in a cool, dry place. Discard as indicated on the packaging.

Similar Supplements

• Black tea
• Green tea
• Kudingcha (Ilex latifolia and Ilex kudingcha)
  
• Oolong tea
• White tea
  
• Yaupon holly (Ilex vomitoria)
• Yerba mate (Ilex paraguariensis)
  

Like guayusa, kudingcha, yerba mate, and yaupon holly are derived from the holly tree. Unlike other holly-based and regular teas, including black, green, white, and oolong teas, guayusa tea does not taste bitter.

Since guayusa and the teas listed above all contain caffeine, it is important not to exceed 400 milligrams (mg) of caffeine per day.

Sources of Guayusa & What To Look For

Although guayusa tea is available as tea bags and powder, you are more likely to find guayusa in loose-leaf form.

Guayusa Supplements

Guayusa is more commonly found in tea form but is also available as a loose-leaf extract capsule. Please consult with your healthcare provider before starting guayusa extract supplement.

Guayusa is primarily a product of organic agriculture, presenting minimal risk of contamination by agriculture pesticide residues. However, if higher-yield agricultural methods using pesticides are adopted, then the risk of contamination of pesticide residues will increase. In general, opt for organic guayusa tea leaves.

Summary

Guayusa tea is a caffeine-containing holly tree from the Amazon rainforests that can serve as a coffee alternative. Alertness, antioxidant, and anti-inflammatory properties are some of the possible health benefits of guayusa tea. While guayusa tea presents no greater risk to consumers than green tea or yerba mate, it can cause restlessness and difficulty sleeping due to its caffeine content. 

Please talk with your healthcare provider if you're consistently tired and using guayasa or other caffeine products to get through the day. Persistent energy issues could be related to anything from thyroid conditions to sleep apnea to iron deficiency. It's wise to treat the root cause in these situations as, left untreated, they can have long term effects on your health.

Caffeine should be used cautiously if you are pregnant and breastfeeding, are a child or adolescent, have sleep disorders, chronic headaches, anxiety, irregular heart rate, high blood pressure, or take certain medications or supplements.