Does Pepsi Zero have more caffeine than Diet Pepsi?

January 9, 2026 •

3 min read

As of January 2023, PepsiCo significantly reformulated Pepsi Zero Sugar in the United States, which included a reduction in caffeine, altering the long-standing comparison between it and Diet Pepsi. Before this change, Pepsi Zero had significantly more caffeine than Diet Pepsi, a key point of differentiation.

Quick Summary

Recent changes to Pepsi Zero's US formula resulted in its caffeine level becoming similar to or only slightly higher than Diet Pepsi's, differing significantly from the original formula that had almost double the caffeine.

Key Points

US Reformulation: In 2023, PepsiCo significantly reduced the caffeine in the American version of Pepsi Zero Sugar.
Similar US Caffeine Levels: The post-2023 US Pepsi Zero contains roughly 38 mg of caffeine per 12 oz can, which is very similar to Diet Pepsi's ~36.7 mg.
International Difference: Canadian and other international versions of Pepsi Zero (sometimes still called Pepsi Max) maintain a higher caffeine content, sometimes reaching up to 69 mg per 12 oz.
Distinct Sweetener Blends: Pepsi Zero uses a blend of aspartame and acesulfame potassium (Ace-K), while Diet Pepsi primarily uses aspartame, which creates different taste profiles.
Taste Profile Shift: The US reformulation of Pepsi Zero was also aimed at providing a flavor closer to that of regular Pepsi, a departure from its original bolder taste.
No Longer 'Max' Caffeine: The original marketing hook for Pepsi Zero focused on maximum flavor and high caffeine; this is no longer the case for the US market after the reformulation.

A Look at the Caffeine Numbers

For years, the distinction was clear: Pepsi Zero Sugar (formerly Pepsi Max) had a much higher caffeine content than Diet Pepsi. The original marketing angle for Pepsi Zero often centered on its 'max taste' and higher-than-average caffeine kick. However, the American version of Pepsi Zero underwent a major reformulation in early 2023, fundamentally changing the landscape of this comparison. The caffeine level in the US version was reduced to be much closer to that of Diet Pepsi.

The North American Reformulation and Its Impact

In January 2023, PepsiCo announced a 'new and improved taste' for Pepsi Zero Sugar in the United States. This update involved several key changes beyond just flavor: removing ginseng, adjusting the sweetener blend, and reducing the caffeine content. A 12-ounce can of the previous US formula contained about 69 mg of caffeine, nearly double the amount found in Diet Pepsi. After the change, the US version's caffeine content was brought down to approximately 38 mg per 12-ounce can, putting it almost on par with Diet Pepsi. This was a significant shift for consumers accustomed to the higher-caffeine version.

International and Older Formulas

It is important to note that this reformulation did not apply everywhere. For instance, the Canadian version of Pepsi Zero Sugar was unaffected and maintains a higher caffeine level, around 50 mg per 355 mL can (which is about 12 fluid ounces). Additionally, the European version, often still labeled as Pepsi Max, also retains a higher caffeine content. This means that depending on your location or if you are consuming an older product, the caffeine content can differ substantially. Always checking the nutrition label is the most reliable way to know for sure.

Why the Variation in Caffeine?

Caffeine is added to cola for two primary reasons: its mildly stimulating effect and its bitter flavor. This bitterness helps balance the intense sweetness from artificial sweeteners like aspartame and acesulfame potassium (Ace-K). The specific balance of these ingredients is precisely calibrated by manufacturers to create distinct taste profiles for different products.

Factors Affecting Caffeine Content:

Target Market: Companies sometimes adjust caffeine levels to appeal to different consumer demographics or regional preferences. Pepsi Zero was historically aimed at those who wanted a bolder, 'max' taste experience.
Sweetener Blend: The combination of artificial sweeteners, such as aspartame and Ace-K, can influence the bitterness of a drink. Adding or subtracting caffeine can help compensate for these flavor changes.
Reformulations: As with the US Pepsi Zero, a company may change a product's formula to improve the taste, respond to consumer feedback, or differentiate it from other products in their line.

A Tale of Two Sweeteners and Taste

Beyond caffeine, the differences in sweetener blends give each soda its unique taste profile. Diet Pepsi has traditionally relied on aspartame for its sweetness. Pepsi Zero, on the other hand, utilizes a combination of aspartame and acesulfame potassium (Ace-K). This dual-sweetener approach in zero-sugar sodas is common and can create a smoother, fuller flavor that more closely mimics the taste of a regular, sugar-sweetened cola. The pre-2023 US Pepsi Zero, with its higher caffeine and additional ginseng, offered a distinctly bolder experience than Diet Pepsi. With the reformulation, the taste profiles have moved closer, though subtle differences in the sweetener blend and ingredients still persist.

Comparison of Pepsi Zero vs. Diet Pepsi


Feature	Diet Pepsi	Pre-2023 US Pepsi Zero	Post-2023 US Pepsi Zero	Canadian Pepsi Zero
Caffeine (per 12 oz)	~36.7 mg	~69 mg	~38 mg	~50-69 mg
Sweeteners	Aspartame	Aspartame + Ace-K	Aspartame + Ace-K	Aspartame + Ace-K
Taste Profile	Crisp, classic 'diet' flavor	Bolder, more intense cola flavor	Smoother, closer to regular Pepsi	Bolder, more intense cola flavor
Special Ingredients	No	Ginseng (removed in 2023)	No ginseng	Ginseng

Conclusion: The Final Word on Caffeine

To answer the question directly: it depends on which version of Pepsi Zero you are referring to. For consumers in the United States, the 2023 reformulation means that Pepsi Zero no longer has significantly more caffeine than Diet Pepsi; their caffeine levels are now very similar. However, international versions, such as those sold in Canada, still retain the higher caffeine content. The choice between these two zero-calorie beverages is now more complex than just a simple caffeine comparison, with differences in taste profile, artificial sweeteners, and regional availability being equally important considerations.

For more information on caffeine guidelines, you can visit the U.S. Food and Drug Administration website.

Frequently Asked Questions

In North America, Pepsi Zero Sugar was formerly known as Pepsi Max. However, the product was reformulated in the US in 2023, so the US version of Pepsi Zero is not the same as the current international versions of Pepsi Max, which often have higher caffeine levels.

The reformulated US Pepsi Zero Sugar was specifically designed to have a taste profile that is closer to regular Pepsi than Diet Pepsi's crisper flavor.

The reformulation was a business decision made to improve the taste and differentiate the product within the market. It was marketed as having a 'new and improved taste' to appeal to consumers.

Based on typical 12-ounce cans, Diet Pepsi usually has slightly more caffeine (~36.7 mg) than Coke Zero (~34 mg). However, caffeine levels in different soda brands can vary.

Both Diet Pepsi and Pepsi Zero are calorie and sugar-free. The health implications are considered similar, though the use of different artificial sweeteners means personal tolerance or preference may differ.

No, this is not always the case. Pepsi Zero and Diet Pepsi are just one example, and caffeine content varies widely by brand and formulation, as seen with Coke Zero having less caffeine than Diet Coke.

For packaged products in the US, manufacturers are not required to list caffeine amounts on nutrition labels unless it is added as a standalone ingredient. However, many voluntarily list it. The most accurate way is to check the product facts on the manufacturer's website.