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Caffeine in Coke Zero vs Diet Coke: Which Has More? 2024 Breakdown

Coke Zero vs Diet Coke

There’s a bit of confusion between Coke Zero and Diet Coke. After all, they are both sugar-free, zero-calorie alternatives to regular Coca-Cola. Diet Coke has been around since 1982, while Coke Zero made its appearance in 2005. Both sodas have a very similar list of ingredients and appeal to diet soda lovers, but is there a difference in their caffeine content?

Coke Zero and Diet Coke both contain caffeine and have caffeine-free versions available on the market. So which product has more caffeine and how big is the difference? We pulled the information directly from Coca-Cola themselves, here’s what we found out.

Coke Zero contains 34 mg of caffeine per can, whereas Diet Coke contains 46 mg.

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A Quick Look at Caffeine Content: Coke Zero vs Diet Coke

Coke Zero Diet Coke
34 mg per 12 fl oz 46 mg per 12 fl oz

How Much Caffeine in Coke Zero?

When checking out the nutrition facts for Coke Zero, we found out that there are 34 milligrams of caffeine per 12 fluid ounces. Each can of Coke Zero is a total of 12 ounces. For those that prefer to drink the 16.9 fluid ounce bottles you find in vending machines, at gas stations, or the grocery store, you are looking at 48 milligrams of caffeine for the bottle. The amount of caffeine remains the same for all flavor varieties of Coke Zero as well.

two cans of coke zero
Image Credit: Chenyu Guan, Unsplash

How Much Caffeine in Diet Coke?

Diet Coke has Coke Zero beat in the overall caffeine amount by 12 milligrams. Diet Coke contains 46 milligrams of caffeine per 12 fluid ounce can. This translates to 65 milligrams of caffeine per 16.9 fluid ounce bottle. Caffeine gives a distinct flavor profile and adds a slightly bitter taste, which explains why Diet Coke and Coke Zero have different tastes despite all of their similarities.

a can of diet coke at the beach
Image Credit: Corrie Miracle, Pixabay

Where Does the Caffeine Come From in Coke Zero and Diet Coke?

Caffeine is a chemical compound that is a central nervous system stimulant. It is naturally produced in over 60 different plants, including coffee beans, cocoa beans, kola nuts, tea leaves, and yerba mate leaves. Though caffeine is naturally occurring, scientists have also created a synthetic version that is widely used in the beverage market because it is cheaper and easier to produce.

Synthetic caffeine is made with a combination of carbon, oxygen, and nitrogen, which is called urea and chloroacetic acid. Synthetic caffeine and natural caffeine are identical at the chemical level, so there is no difference in taste between the two.

In the past, Coca-Cola used caffeine that was extracted directly from the kola nut and sometimes the cocoa plant when crafting their sodas. However, in modern-day thanks to the advancements in science and technology they now use synthetic caffeine in their formula.

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Caffeine in Coke Zero vs Diet Coke: The Bottom Line

The bottom line is that Diet Coke has 12 milligrams more caffeine per 12-fluid-ounce can, making it the clear winner for overall caffeine content. While the caffeine used in Coca-Cola products used to be from natural sources like the kola nut, the company now uses synthetic caffeine in its colas.

Caffeine content plays a large role in taste, adding a certain level of bitterness. This is why these two sugar-free, zero-calorie options differ so much in taste. Coke Zero with the lower caffeine content of 34mg per 12 fluid ounces is meant to mimic the taste of the original Coca-Cola more so than the more bitter, higher caffeinated Diet Coke with 46mg per 12 fluid ounces.

Featured Image Credit: (L) shche_ team, Unsplash | (R) Kenny Eliason, Unsplash


Ollie Jones

Oliver (Ollie) Jones is a zoologist and freelance writer living in South Australia. Originally from the US, he thought he loved coffee before his big move down under, but his discovery of the flat white and the cafe on every corner has taken his coffee passion to a whole new level. He's so excited to share his knowledge and experience with readers worldwide (and keep testing coffee drinks while he's at it).

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