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Relentless Energy Drink Review (Honest Opinion)

Manufactured in 2006 by the Coca-Cola company, Relentless has seen a constant increase in popularity since then.

Relentless is just as good as any other energy drink and might even fit your preferences better.

It contains a generous 160mg of caffeine in a 500mL can, 24g of sugar, 108 calories, and other ingredients such as Taurine, Niacinamide, and Erythritol.

Of course, there’s more to Relentless than that. Read my review to have the full story!

Ingredients in Relentless Energy Drink

Relentless contains the usual ingredients present in most energy drinks, I have compiled this list of ingredients in an easy-to-navigate table below.

Relentless Ingredients
Ingredients from a Relentless can
Ingredient TypeIngredients
EnergizersCaffeine, Guarana Seed Extract
WaterCarbonated Water
PreservativesPotassium Sorbate, Sodium Benzoate
Acidity RegulatorSodium Citrate
VitaminsTaurine, Niacinamide,
Pantothenic Acid, Pyridoxine,
Artificial SweetenerSucralose
AcidCitric Acid
Flavour EnhancerErythritol
ColourCaramel E150d
Relentless Ingredients

Nutritional Content in Relentless

The table below outlines all the important quantities of various products present in Relentless.

ContentQuantity (500mL)Daily Value (%DV)
(108 kcal)
of which Sugar
Relentless Nutrition Facts

Caffeine in Relentless

Relentless comes with 160mg of caffeine in a 500mL (16 fl. oz) can.

The FDA recommends that adults can only consume up to 400mg of caffeine per day.

Although the amount of caffeine present in Relentless is well within the FDA guidelines, you must remember caffeine affects us all differently.

You might not handle the 160mg in Relentless well, so it’s better that you start with small doses first.

Sugar in Relentless

Relentless has 24g of sugar in its regular, 500mL can.

Although some other energy drink brands have gone completely sugar-free and use artificial sweeteners, Relentless has gone for a slightly different path.

Natural sugar and the popular artificial sweetener, Sucralose, is blended and added in Relentless. This, along with other essential ingredients, give it its signature taste.

Calorie Content of Relentless

Relentless has 108 calories in its 500mL (16 fl. oz) can.

This amount is insignificant compared to the daily intake limit recommended to individuals, 2500 for men and 2000 for women.

However, if you’re on a calorie-restricted diet or plan to lose weight, the additional calories that Relentless brings may be a hurdle to your fitness plan.

In that case, you can always switch to calorie-free energy drink brands.

Is Relentless Healthy?

While Relentless won’t harm you if you have a can or two per day, it isn’t exactly healthy either.

The calorie content present in Relentless will impact your weight, so if you like to keep your daily calorie count as low as possible, Relentless isn’t the right option for you.

Like anything else, drinking Relentless in excess will also cause adverse effects on your health. A caffeine overdose can result in the following side effects:

  • Irregular heartbeat
  • Shakiness
  • Vomiting
  • Confusion
  • Panic attack

Below is a video that provides detailed information on what other effects too much caffeine can have on you.

Why Do People Drink Relentless?

You can drink Relentless for various reasons, the most common being to get an energy boost.

Energy drinks are also popular among athletes, who might want to drink them before an important match and maximize their performance.

Students also rely on energy drinks to study the night before a difficult exam and keep sleep at bay.

Others also drink Relentless simply because of its taste. It is understandable to get hooked to any of the seven flavours of Relentless.

Is Relentless a Pre-Workout Energy Drink?

Man exercising
Relentless may give you the power boost you need prior to working out.

If you’re working out to lose weight and need to follow strict diet plans, Relentless might not be the right option. Relentless isn’t a zero-calorie drink. The sugar and calorie content present in it might hamper your progress.

However, if you’re exercising to build muscle, Relentless is the perfect option.

Its caffeine content can energize you before a workout and enable you to carry out more strenuous exercises.

Its calorie amount will also add to the required 2800 calories you need to build a pound of muscle.

Is Relentless Energy Drink Bad For You?

Relentless can become harmful if you drink more than two cans a day for a time.

The following are some of the long-term side-effects that can occur from misusing energy drinks and drinking excessively:

Chronic Insomnia

Continuously consuming caffeine to stay awake at night can cause you to be unable to sleep even on nights you haven’t had caffeine.

Common symptoms of insomnia include:

  • Feeling tired even after waking up
  • Waking up early and unable to sleep again
  • Feeling tired and irritable during the day


Caffeine triggers your fight or flight response. Long-term and excessive intake of caffeine can cause you to feel jittery and nervous.

Caffeine dependence is also known to heighten the risk for psychological conditions like antisocial personality disorder, anxiety, and depression.

Can You Drink Relentless Energy Drink Everyday?

Relentless can be consumed every day as long as you limit yourself to one can a day.

While one drink a day should be alright, I recommend that you only drink Relentless every other day to be safe.

Excessively consuming Relentless every day can cause adverse side effects and caffeine dependency.


Relentless, like any other energy drink, offer many excellent benefits when taken into moderation. Some of these benefits are:

  • Boosts energy.
  • Enhances stamina and alertness.
  • Moderate amount of caffeine.
  • Improves cognitive and physical performance.


Despite the amazing benefits, coupled with it are some consequences when not taken into moderation and might cause some health problems. A few of these consequences are:

  • Caffeine intoxication
  • Heart problems
  • Disruptions of sleep
  • Elevated blood pressure level.
  • Increase heart rate
  • Elevated glucose level
  • Dependence
  • The risk of addiction.

Relentless Energy Flavours: Which one is best?

Relentless comes with seven unique flavours; I have listed these below:

  • Origin
  • Mango
  • Lemon Ice
  • Cherry
  • Passion Punch
  • Apple Kiwi

After trying Relentless, I am stoked that it doesn’t have any weird aftertaste. It is a refreshing and fruity drink, so Relentless must be for you if you like fruity flavours.

Apart from these, Relentless also has another flavour to boast, and that is its Zero formula. Relentless Zero is their zero-sugar version, which is perfect for those who are conscious of their sugar intake daily.

Try out all and be the judge of which one you think is the best!

Relentless Energy Drink Alternatives

If Relentless doesn’t fit your requirements and you’re looking for something different, here are a couple of alternatives you might want to consider.

Xyience Energy

Xyience on table top
Xyience Energy Drink – Frostberry Blast

Xyience has been in the market for over a decade and has been catering to thousands of happy customers.

It comes with around 180mg of caffeine in a 16 fl. oz can, a more considerable amount than Relentless.

Its zero calories and zero-sugar formula make it suitable for people on diets looking to add a good energy drink to their routine.

Bing Energy

Bing energy drink cans
Bing Energy

Bing is another famous brand founded by a husband-wife duo in their quest to create perfect berry-flavoured drinks that act as energy boosters.

A 12 fl. oz can of Bing contains 120mg of caffeine. While this amount is lesser than Relentless, Bing can be suitable for you if you drink energy drinks multiple times a day.

Other noteworthy mentions:

Final Thoughts

The final verdict from me would be, yes, Relentless is worth the money.

It has a fruity punch that will be liked by most, and there’s a sugar-free version that is suitable for those who are sugar sensitive. It also has a reasonable calorie and caffeine content, but make sure that you don’t go beyond your daily limit.

Relentless is available in sachets and has free samples, too, so you can choose what flavour you’d like to have. The drink is priced at around $1.30 per 500ml (16 fl.oz) can and is available to buy in your local stores and online shopping websites; however, the shipping fee is excluded.

It is best to know your limits first and seek advice from a professional before going more than twice a day with Relentless.

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About Adrian Carter

Adrian writes about energy drinks and their ingredients to shine a light on the facts behind the brand names.


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