Relentless ENERGY DRINK Inferno

Posted on March 20, 2021 | Last updated February 5, 2025

Relentless ENERGY DRINK Inferno
This is Inferno, the first orange-flavored energy drink in the Relentless series. Initially, it was released without specifying the flavor, and only later was the orange flavor clearly indicated.

This time, I will be reviewing the early version of Inferno, produced in 2009.

Relentless ENERGY DRINK Inferno

Manufacturer	Coca Cola
Country of Origin	UK
Price	1.39 EUR
Flavor	Orange
Total rating	★★★☆☆

Author information Author: Energy Drink-kun

In 2001, while living in the United States, I encountered energy drinks through the dance scene and was deeply impressed. After returning to Japan, I found that energy drinks were considered novelty beverages, so I established a comprehensive website in 2013 to share the true appeal of energy drinks. As an energy drink enthusiast, I began drinking them seriously again, collecting over 7,000 varieties of energy drinks from various countries. I am also active as a critic and expert, receiving media interviews.

Flavor of Relentless ENERGY DRINK Inferno

When poured into a glass, it shows a rich orange with 12 years of deterioration. You can even see some floating solids. Originally, it had a bright and vivid orange color.
Relentless ENERGY DRINK Inferno Flavor
When you take a sip, the original orange fruit flavor is accompanied by the astringency due to deterioration, which still gives a reasonable orange flavor. The fresh orange sweetness is completely gone, so it’s best to think of it as an orange flavor with an emphasis on sourness and astringency.

Since the juice content is 5%, the deterioration seems to have been kept to a minimum. The carbonation provides a nice and strong kick, and if this had been released as is, it would likely be accepted as a bitter orange flavor (^_^;)

It was just right, so I opened the latest (although from 2013) orange version to compare. Let’s see how it compares.
Relentless ENERGY DRINK Inferno Old vs New Comparison
You can clearly see the difference in color when placed side by side. Originally, Inferno had this vibrant orange color.

Naturally, the 2013 version offers a more refreshing and subtle sweetness with a noticeable fruitiness. Even though the product name changed, the base flavor and aroma of the orange remain the same, so drinking this version of Inferno makes it easy to understand how the flavor has deteriorated over time.

Energy Ingredients of Relentless ENERGY DRINK Inferno

Relentless ENERGY DRINK Inferno
It contains 160mg of caffeine, 2000mg of taurine, and guarana. The orange juice content is 5%.

Design of Relentless ENERGY DRINK Inferno

The design of Relentless Inferno varies depending on the time of release and the country. The left image shows the early version of Relentless Inferno from the UK, while the right shows a later version released in the UK.
Relentless ENERGY DRINK Inferno Design
The early version of Relentless Inferno featured a face design, while the later version depicted bones and a brain. Eventually, the product was rebranded as Relentless ORANGE. This bone-and-brain design was carried over into Relentless ORANGE.

Relentless ENERGY DRINK Inferno
Inferno’s design changed slightly depending on the country of sale, and in versions with higher contrast in the center, the design details are clearer.

By the way, the face design originally used for the first release of Relentless Inferno is quite similar to the early release of Relentless ORIGIN.
Relentless ENERGY DRINK Inferno
On the left, the face with flesh is Inferno, while on the right, the skeletal face is ORIGIN.