Dr. Robert Cook - Is It Bad For You? Approved by Dr. Robert Cook

Is G Fuel Bad For You?

Also Known As: G Fuel Energy Drink Formula



Short answer

If you're over eighteen and in good health, G-Fuel is like a very strong energy drink with lots of extra antioxidants. If you're underage, pregnant, diabetic, or have a medical condition involving serotonin levels or the thyroid, you should check with your doctor first.



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Long answer

The Food and Drug Administration does not review the safety or effectiveness of dietary supplements before they go to market. That's the responsibility of the manufacturer. This means it can be difficult to determine whether or not different supplements on the market are safe to take.

G-Fuel has about as much caffeine as a very strong cup of coffee. It's got more caffeine than a Red Bull but less than heavy-hitting energy drinks like Spike. It also has significant amounts of antioxidants, which protect your cells and DNA by mopping up dangerous free radicals floating around in the body.

G-Fuel has a set of "energy complex" ingredients to give you energy. They include taurine, a caffeine-like chemical which is standard in most energy drinks and works on the heart; citrulline, which athletes sometimes take to reduce fatigue; and L-carnitine, which rebuilds mitochondria and increases insulin sensitivity. Also of note are mucuna pruriens, a plant, and L-DOPA, a chemical found in mucuna pruriens. L-DOPA changes the process by which the brain produces serotonin and dopamine. 

There's also a set of "focus complex" ingredients to help you focus. Vinpocetine, bapoca extract, and huperzine all supposedly help memory and focus. None have been shown in the scientific literature to definitively work, but they seem to be safe. Tyrosine, another focus complex ingredient, is also considered safe but may affect the thyroid or interact with L-DOPA.

There are a lot of active ingredients here - enough that the scientific literature can't completely rule out dangerous or unexpected reactions. The presence of L-DOPA, which sometimes interacts with focus complex ingredient tyrosine, should be a red flag for anyone who keeps a close watch on their serotonin levels. If your brain produces too much or too little serotonin, or if you're taking medication (such as an SSRI or MAOI) that affects the way serotonin is produced in your brain, you should talk to your doctor before taking G-Fuel. You could get serotonin syndrome from combining the L-DOPA in the G-Fuel with your medication. Your brain will flood with serotonin, and you could experience a whole host of nasty symptoms, including sweating, tremors, increased body temperature, and nausea.

If you're diabetic, you already know to keep a close eye on your diet and a closer eye when considering dietary supplements. L-carnitine is an amino acid in G-Fuel which helps your body break down glucose and makes it more sensitive to insulin . It's even been investigated as a potential treatment for type II diabetes. Anyone with diabetes should consult with a doctor before taking nutritional supplements that will alter the way that their body processes glucose or produces insulin.

If you have thyroid problems, talk to your doctor about the tyrosine in G-Fuel, as it interacts with the thyroid and may interfere with your medication.

G-Fuel's warning label calls out some other specific groups who may place themselves at risk by taking the supplement: those with high blood pressure, those with heart problems, and those who are pregnant or considering pregnancy. This is good advice not just for G-Fuel but for energy drinks in general.

Parents of children and teens should also be careful with G-Fuel. Other energy drinks, like Red Bull, deliberately avoid marketing to children younger than 12. G-Fuel does not. The American Academy of Pediatrics recommends that kids and teens avoid energy drinks entirely - caffeine and other stimulants can mess up their sleep cycle, slow brain development, and change their heart rate.

Data on how many minors drink energy drinks and the connection to their health is still thin. At least one 10-year-old boy has been hospitalized in Massachusets after drinking too much G-Fuel at a party.

Possible short-term side effects

  • stomach pain
  • nausea
  • tachycardia
  • increased heart rate
  • sweating
  • interaction with certain medications

Ingredients to be aware of


  • good source of antioxidants
  • can increase serotonin
  • speeds up metabolism
  • may increase focus
  • energy boost

Our Wellness Pick (what is this?)

Zipfizz Energy Mix

  • Zero sugar content
  • Rich in vitamin B12
  • Promotes hydration
  • Multi-vitamin blend
  • Variety of flavors
Learn More!

Thank you for your feedback!

Written by Sean McNulty
Published on: 09-02-2016
Last updated: 12-15-2023

Thank you for your feedback!

Written by Sean McNulty
Published on: 09-02-2016
Last updated: 12-15-2023

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