GU Energy Gel Review: Fuel Your Performance

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There's no question that high level endurance sports require proper fueling to maximize performance. The last thing an athlete wants to experience is "bonking" or "hitting the wall," terms that refer to severe fatigue and loss of energy caused by lack of carbs in your system. To prevent this, experts recommended athletes consume a carbohydrate-containing meal within two hours prior to training and supplement with about 25 grams of carbs per hour of intense activity. However, this may be easier said than done.

One hurdle that athletes commonly run into is refueling during exercise, since it's difficult to eat or drink while on the move. To solve this dilemma, sports nutrition companies produce energy gels that contain fast-digesting carbohydrates in an easy to consume package. One such supplement is GU Energy Gels which contain carbs in addition to a number of other performance-enhancing ingredients. They've been around for almost 30 years and have become the go-to option for intra-workout portable energy. Still, you may wonder, what makes this product effective?

The ACTIVE Reviews Team took a closer look to provide you with an in-depth GU Energy Gel review and explain just how it works.

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What is GU Energy Gel?

GU Energy Gel is a sports nutrition product designed to provide athletes with convenient, quick-digesting carbohydrates to deliver immediate and sustained energy during high-intensity exercise. In addition to the fast-acting carbs, the caffeinated version of these gels contains caffeine sourced from green tea extract, to give users an extra energy jolt and help maintain focus. For hydration support, each packet provides sodium and potassium to keep your electrolytes replenished. While most often used by endurance athletes, GU Energy Gel can also be taken by athletes participating in team sports or shorter duration events for refueling purposes.

How Does GU Energy Gel Work?

During sustained moderate- to high-intensity exercise, our bodies burn through a significant amount of energy. For example, runners burn about 100 calories per mile. During endurance exercise, our bodies depend primarily on glucose for energy. This comes from circulating glucose in the blood, as well as glycogen, our body's stored form of carbohydrates. Even if you consume a solid pre-training meal, you'll still want to refuel with carbs during exercise bouts lasting an hour or longer to prevent bonking.

GU Energy Gels provide around 22 grams of carbohydrates per serving that can be quickly digested, absorbed, and immediately used for energy. On top of that, the caffeinated version contains 20-40 milligrams of caffeine, a well-known stimulant that can help you bust through fatigue. Another important aspect of sports performance is hydration. GU Energy Gels support hydration by providing 60 milligrams of sodium and 40 milligrams of potassium per serving to keep your electrolyte stores topped off. As an added bonus, they provide key amino acids to help prevent muscle protein breakdown during training.

The best time to utilize GU Energy Gels is during moderate- to high-intensity exercise lasting an hour or longer. This is when your body requires supplemental carbs the most. If you are participating in a shorter duration event lasting less than an hour but still want to fuel up, you can take a gel before training.

GU Energy Gel Ingredients


Our Rating Scale

Price/affordability (Scale of $-$$$):

Prices depend on a number of factors, and tend to fluctuate over time, so we've kept our affordability rating scale simple so you can easily see how products compare:

$ = under $1 per serving

$$ = $1-2 per serving

$$$ = over $2 per serving

Flavor Options (Scale of 1-3):

When it comes to dietary supplements that you take frequently, or even daily, options are important. And while your protein powder or pre-workout doesn't have to taste good to be effective, having several flavors to choose from can make it easier to stick with your fitness and health goals.

N/A = Unflavored

1 = 1-2 flavor options

2 = 3-4 flavor options

3 = 5 or more flavor options


  • Price:$$
  • Flavor options (scale of 1-3): 3
  • Artificial sweeteners: None noted
  • Serving size: 1 packet (32g)
  • Calories per serving: 100
  • Protein per serving: 0g
  • Carbs per serving: 22g
  • Fats per serving: 0g


Benefits of GU Energy Gel


1. Keeps Glycogen Stores Topped Off

Glycogen is our body's stored form of carbohydrates, located mainly in the muscles and liver. When participating in taxing exercise, glycogen stores are depleted, potentially leading to decreases in performance. GU Energy Gels provide quick-digesting carbs that can help maintain glycogen.

2. Provides Caffeine for Added Energy

The caffeinated flavors of GU Energy Gel provide 20-40 milligrams of caffeine that can give you an energy boost whether you are training for a marathon or completing a tough rowing workout. Caffeine stimulates the central nervous system to reduce fatigue and improve mental focus.

3. Contains Important Electrolytes

Electrolytes are minerals in the body that carry an electrical charge and play a role in fluid balance. When you sweat, some of these electrolytes are lost and should be replenished during and after intense training. GU Energy Gels provide around 60 milligrams of sodium and 40 milligrams of potassium, the body's major electrolytes.

BUY: GU Energy Gel

FAQs About GU Energy Gel

What does GU Energy Gel do?

GU Energy Gel contains specific types of carbohydrates that can be rapidly digested and used for energy in the body. In addition, the caffeinated form provides 20-40 milligrams of caffeine to help sustain energy levels and keep you focused. The amino acids contained in the gels help to prevent muscle protein breakdown during exercise. Last but not least, they provide a solid dose of electrolytes, which are important minerals needed to maintain hydration.

Is GU Energy Gel good for you?

For athletes participating in longer duration, moderate- to high-intensity activities that require supplemental carbohydrates to maintain energy levels, GU Energy Gels can be highly beneficial to prevent bonking. Other active people participating in shorter duration, less intense training may not need to supplement with carbs, so taking an energy gel may just be adding extra sugar to your diet. Consider the energy demands of your sport to help you determine if energy gels will be good for you.

When should I use GU Energy Gel?

GU Energy Gels are designed to be consumed every 45 minutes when performing activities lasting longer than an hour. The instructions advise users to take an energy gel 5 minutes before every 45-minute period of exercise. For events lasting multiple hours, more than one packet should be consumed. For athletes completing shorter duration training or events, energy gels can be taken before the activity starts.

How do you take GU Energy Gel?

This product comes in convenient packets with a tear-off top that can be easily removed while training. Simply rip off the top and squeeze the contents of the package into your mouth, disposing of the wrapper. It is then recommended that you wash it down with some water to allow for maximum absorption.

How do you get GU Energy Gel?

GU Energy Gel is widely available and can be purchased directly from GU or from third-party retailers such as Amazon, REI, Target, Walmart, Dick's Sporting Goods, The Vitamin Shoppe, and GNC.

What can I use instead of GU?

While GU Energy Gels provide a convenient source of carbs to keep you fueled for performance, there are certainly alternatives for those who don't have access or don't wish to use them. Some common alternatives include bananas, sports drinks, and dried fruits. These also provide valuable carbs to keep you performing at a high level. Some people even choose to make their own energy gels out of ingredients like honey and molasses.