Is Guarana Bad For You?: Everything You Need to Know

Is Guarana Bad For You?: Everything You Need to Know

To really blow the lid off your workouts you need to get the right pre workout ingredients. You’ll feel invincible as you smash the free weights, crush the cardio and make the gym tremble under your feet.

Make informed choices about your prep supplement and you’ll feel like you can take on the world.

Get the wrong one though and you’ll feel flat, wired and weak. Not only will you waste your money but you’ll sacrifice your gains too.

In this article we’ll take a look at guarana – a plant seed from South America.

Is it a good pre workout choice?

Let’s find out…

  • What is guarana?
  • Is it an effective pre workout?
  • Is it safe?

What is Guarana?

Guarana (Paullinia cupana) is a climbing plant native to South America and in particular, the Amazon.

It often reach heights of over 10 meters when mature, clings to other trees for support as it develops, and has large leaves and clusters of flowers.

The guarana tree is characterized by it’s bright red fruits with black seeds and white arils. Its uncanny resemblance to an eyeball has led to a number of stories and myths about how it was created.

Named after the Amazonian tribe Guarani, guarana extract is commonly used as a herbal remedy in traditional medicine, as a way of boosting the energy of indigenous tribesmen.

The seeds are fermented for a few days before they are heated and then ground into a brown powder.

Guarana has become a popular ingredient in the energy drink industry over the last few years. You’ll find it nowadays as an ingredient in a range of different foods:

  • Fruit juices
  • Confectionery
  • Dietary and herbal supplements
  • Pre workouts

Nutrient Content

Guarana contains a number of bioactive nutrients such as saponins and tannins, which have been attributed to the nutrient’s ‘psychoactive’ properties (a stimulant that activates the nervous system). They may also offer some antioxidant benefits too.

It also provides dietary fiber from pectin and a number of procyanidins too.

The most potent bioactive ingredient in guarana is guaranine – a chemical identical to caffeine.

Of course, when you think of caffeine you might think coffee, green tea or soda – but guarana also provides a stimulatory effect due to it 2.5-5% caffeine content [1].

It also contains the purine alkaloids theobromine and theophylline too.

Guarana seeds and powder on a wooden table
  • Key Point: Guarana is a psychoactive stimulant used traditionally as an energy booster by indigenous Amazonian tribesman.

Could Guarana Be An Effective Pre Workout?

Guarana doesn’t promote fat loss

One of the reasons you use a pre workout might be to shred more fat.

Caffeine is a well-researched thermogenic, with numerous studies showing that its adenosine inhibiting effect boosting fat oxidation, metabolic rate and total daily energy expenditure.

Guarana however has not been found to boost fat loss any more than caffeine alone.

To date there is only one animal study that shows a trend of slowed weight gain in overfed rats [2]. In the study, rats were given a high dose of 821 mg per kilogram of body weight over a 2-week period. And after taking the supplement they reported that weight gain had slowed down slightly. That’s all.

It’s worth noting though that guarana was not given to the rats in isolation, but as part of a stack with a common therapeutic drug too.

According to one research paper, “the effects of guarana have been largely neglected in the human literature” [3]. And because it’s so understudied, there isn’t actually a recognised recommended ‘safe’ dose for humans.

Might be toxic at high doses

At first glance you might think that guarana is more effective than its more well-researched counterpart, caffeine anhydrous. Guarana has a slightly higher caffeine content than something like coffee and is reported to give you a more focused and less ‘jittery’ stimulatory effect too.

The problem is though that it’s actually pretty difficult to quantify the exact amount of caffeine in guarana pre workouts and many form part of proprietary blends rather than open and honest products. And at bigger doses, guarana might even be harmful too [4].

One case study of a 38-year old woman found that an over-the-counter guarana workout supplement induce various side effects [5]:

  • Seizures
  • Blurred vision
  • Right frontal lobe atrophy

Death from cardiac arrest

Another case study reported the death of a 25-year old woman who died from a cardiac arrest after ingesting a drink containing 10 grams per liter of guarana – well above the tolerable limit in humans [6].

Young woman in sportswear getting ready to run a sprint race

Key Point: Guarana might give you an energy boost, but could be toxic at higher doses.


Guarana is a supplement that derives from the guarana tree. It has been used as a stimulant in indigenous South American tribes for hundreds of years, but has recently become a mainstream food and herbal remedy food additive.

Although used for its energy giving properties, this psychoactive nutrients may be toxic at high doses – it is not an effective pre workout.

Case studies have reported seizures, brain injuries and death from cardiac arrest.

We suggest that you avoid this pre workout and instead focus your attention on safer alternatives such as caffeine anhydrous which will give you a safer stimulant effect.

Smash Your Workouts With 4 Gauge

4 Gauge is an exhaustively researched, all-natural pre workout designed to rip the lid off your gym sessions, sports games or workouts.

Packed with performance-enhancing nutrients such as caffeine, L-theanine and creatine, 4 Gauge will take your training to a completely new level.

  • Smash your workouts – feel your nervous system firing on all cylinders
  • Cell-splitting muscle pumps – harness the power of vasodilation and deliver more nutrients to your muscle cells
  • Determination like never before – feel unparalleled focus and motivation
  • Relentless energy – train for longer without fatigue


  1. Kennedy, DO et al. Improved cognitive performance in human volunteers following administration of guarana (Paullinia cupana) extract: comparison and interaction with Panax ginseng. Pharma Bioch Behaviour. 2004; 79: 401-411
  2. Rodrigues, M et al. Herb-Drug Interaction of Paullinia cupana (Guarana) Seed Extract on the Pharmacokinetics of Amiodarone in Rats. Evid Based Complement Alternat Med. 2012;2012:428560
  3. Haskell, CF et al. A double-blind, placebo-controlled, multi-dose evaluation of the acute behavioural effects of guaraná in humans. J Psychopharma. 2007; 21(1): 65-70
  4. Santa Maria A. Evaluation of the Toxicity within VitroBioassays. Ecotoxicology and Environmental Safety. 1998; 39(3): 164-167
  5. Pendleton, M et al. Potential toxicity of caffeine when used as a dietary supplement for weight loss. J Diet Suppl. 2012; 9(4): 293-8
  6. Cannon, ME et al. Caffeine-induced cardiac arrhythmia: an unrecognised danger of healthfood products. Med J Aust. 2001; 174(10): 520-521

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