Guarana is found in many "energy" drinks. How does it work?
contains caffeine. Caffeine works by stimulating the central nervous
system (CNS), heart, and muscles. Guarana also contains theophylline and
theobromine, which are chemicals similar to caffeine.
GUARANA Side Effects & Safety:
is LIKELY SAFE for most adults when used in typical food amounts or in
medicinal amounts short-term. But it is LIKELY UNSAFE and even deadly,
due to its caffeine content, when taken in high doses or long-term. The
fatal dose of caffeine is estimated to be 10-14 grams (150-200 mg per
kilogram; the “typical” man weighs about 70 kilograms, so a lethal dose
of caffeine for this man would be 10,500-14,000 mg). This is quite a
high dose. Consider that one cup of brewed coffee provides from 95-200
mg of caffeine. However, serious poisoning can occur at doses lower than
150-200 mg per kilogram depending on an individual’s caffeine
sensitivity or smoking behavior, age, and prior caffeine use.
effects depend on the dose. At typical doses, the caffeine in guarana
can cause insomnia, nervousness and restlessness, stomach irritation,
nausea, vomiting, increased heart rate and blood pressure, rapid
breathing, tremors, delirium, diuresis, and other side effects. Large
guarana doses might cause headache, anxiety, agitation, ringing in the
ears, pain when urinating, stomach cramps, and irregular heartbeats.
People who take guarana regularly may experience caffeine withdrawal
symptoms if they reduce their usual amount.
Special Precautions & Warnings:
Pregnancy and breast-feeding:
If you are pregnant or breast-feeding, guarana should be taken with
caution due to the caffeine content. Small amounts are probably not
harmful; however, consuming more than 200 mg/day has been linked to an
increased risk of miscarriage and other negative effects.
Anxiety: The caffeine in guarana might make feelings of anxiety worse.
disorders: There is some evidence from animal research suggesting that
the caffeine in guarana might make bleeding disorders worse, although
this hasn’t been reported in people. If you have a bleeding disorder,
check with your healthcare provider before starting guarana.
Some research suggests that the caffeine in guarana may affect the way
people with diabetes process sugar (glucose) and may complicate blood
sugar control. There is also some interesting research that suggests
caffeine may enhance the warning symptoms of low blood sugar in patients
with type 1 diabetes. Some studies show that the symptoms of low blood
sugar are more intense when they start in the absence of caffeine, but
as low blood sugar continues, symptoms are greater with caffeine. This
might increase the ability of diabetic patients to detect and treat low
blood sugar. However, the downside is that caffeine might actually
increase the number of low-sugar episodes. If you have diabetes, talk
with your healthcare provider before starting guarana.
Heart disease: The caffeine in guarana might cause irregular heartbeat in certain people. Use with caution.
blood pressure: Taking guarana might raise blood pressure in people
with high blood pressure due to its caffeine content. However, this
effect might be less in people who are regular coffee-drinkers or
otherwise use caffeine on a regular basis.
Glaucoma: The caffeine
in guarana increases the pressure inside the eye. The increase occurs
within 30 minutes and lasts for at least 90 minutes after drinking
Osteoporosis: The caffeine in guarana can
flush calcium out of the body through the kidneys. This calcium loss
might help to weaken bones. To minimize this problem, don’t use more
than 300 mg of caffeine per day. Taking calcium supplements may also
help to offset these calcium losses. Postmenopausal women who have a
genetic problem that affects how vitamin D is used by the body should
use caffeine with caution.