Coke Zero Sugar, often called Coke Zero, gets its sweetness in the U.S. from two sweeteners: aspartame and acesulfame potassium, also known as Ace-K. Coca-Cola says the blend is used in its bottles and cans, but recipes can differ by country.
That can surprise people because the drink tastes sweet despite having no sugar. The sweeteners are used in small amounts, not as a spoon-for-spoon replacement for sugar. Both are much sweeter than sugar, so only a little is needed.
Here’s what each sweetener does, how to check the ingredients in your local version, and what health agencies say about aspartame.
What is the sweetener in Coke Zero?
The short answer is aspartame and Ace-K in the U.S. formula. Coca-Cola’s ingredient information identifies both sweeteners in Coke Zero Sugar and notes that ingredients may vary by market. Your can or bottle is the best guide to the version you’re buying.
The U.S. formula lists two sweeteners
U.S. Coke Zero Sugar uses aspartame and acesulfame potassium. These are high-intensity sweeteners, which means they provide a lot of sweetness in small amounts. The ingredient list names what’s used, but it doesn’t tell you how much of each sweetener is in a can.
Coke Zero recipes can vary by country
Coca-Cola notes that sweeteners in its products can differ around the world. Local rules and product formulas may affect both the ingredients and the way they appear on a label. Check the package sold where you live rather than assuming another country’s formula applies to your drink.
Coke Zero differs from regular Coca-Cola
Coke Zero Sugar uses non-sugar sweeteners, while regular Coca-Cola is generally sweetened with sugar. In the U.S., regular Coca-Cola is typically made with high-fructose corn syrup; in some other markets, it uses cane sugar. The recipe depends on where the drink is made and sold.
How aspartame and Ace-K sweeten Coke Zero
Aspartame and Ace-K are separate sweeteners. Both help give Coke Zero its sweet taste, but Coca-Cola doesn’t publish their exact proportions in the drink. Their use doesn’t mean Coke Zero contains a sugar-equivalent amount of either ingredient.
Aspartame adds sweetness without sugar
Aspartame is a high-intensity sweetener used in small amounts. The U.S. Food and Drug Administration (FDA) says it’s about 200 times sweeter than table sugar. It isn’t sugar, and a small amount can provide considerable sweetness.
Ace-K is a separate sweetener
Ace-K is short for acesulfame potassium. “Potassium” is part of the compound’s name; Ace-K is not another name for aspartame. The FDA also describes Ace-K as about 200 times sweeter than sugar and notes that it’s often combined with other sweeteners.
A blend can shape the taste
Food makers sometimes combine high-intensity sweeteners to create a particular flavor. Coca-Cola confirms that Coke Zero Sugar uses a blend, but doesn’t share the exact amounts or explain the precise role of each one. So it’s best not to guess how much of either sweetener is in a can.
Check the can to confirm your Coke Zero formula
A product name alone may not tell you which sweeteners are in your drink. Formulas and packaging can vary by market, and products can change over time. A quick label check gives you the most useful answer for the can or bottle in your hand.
Read the ingredients list
Look for “aspartame” and “acesulfame potassium.” Some labels may use “acesulfame K” instead. In some markets, additive codes may also appear: E951 for aspartame and E950 for acesulfame potassium.
Check the country and product name
Confirm the country where the drink is sold and the exact product name on the package. Coke Zero Sugar and other Coca-Cola drinks marketed as no-sugar or diet options may have different ingredients. Don’t assume one product’s list applies to another.
Compare the package with local product details
Coca-Cola’s website for your country may list ingredients for local products. Compare that information with the package, especially if you’re checking for a specific sweetener. If the two lists differ, use the current can or bottle label as the guide for that product.
What health authorities say about aspartame
Health agencies set limits for aspartame intake and assess the evidence in different ways. Their intake limits are not goals or recommended amounts to consume. They’re safety benchmarks for total daily intake over time.
Acceptable daily intake limits aren’t targets
The FDA’s acceptable daily intake (ADI) for aspartame is 50 milligrams per kilogram of body weight per day. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) sets its ADI at 40 mg/kg/day, a limit it reaffirmed in 2023. These figures cover aspartame from all foods and drinks, not just Coke Zero.
People with PKU need to check for aspartame
People with phenylketonuria (PKU), a rare genetic disorder, need to restrict phenylalanine. Aspartame contains phenylalanine, so U.S. products that contain it must carry a notice. If you have PKU, follow your clinician’s guidance and check each product label.
IARC’s cancer category describes a hazard
In 2023, the International Agency for Research on Cancer (IARC) classified aspartame as “possibly carcinogenic to humans,” or Group 2B. This is a hazard category: it describes the strength of evidence that something could cause harm, not the risk at a typical level of consumption. In the same review process, JECFA kept its ADI at 40 mg/kg/day, as explained in the WHO announcement on the assessments.
Coke Zero’s sweeteners depend on what you’re avoiding
Coke Zero Sugar can be an option for someone avoiding sugar, but it still contains sweeteners. If you’re avoiding aspartame, Ace-K, or another ingredient, check the local ingredient list rather than relying on the “zero sugar” name.
Don’t infer sweetener amounts from the label
An ingredient list tells you which ingredients are present, not the amount of each one. Unless Coca-Cola publishes product-specific amounts, there’s no reliable way to calculate how much aspartame or Ace-K is in a can from the label alone.
Compare drinks by their ingredient lists
Other diet soft drinks may use aspartame, Ace-K, a different sweetener, or a blend. Unsweetened drinks have a different ingredient profile again. Compare the actual labels when choosing a drink, since the product category alone doesn’t tell you which sweeteners it contains.
Conclusion
In the U.S., Coke Zero Sugar uses aspartame and acesulfame potassium, or Ace-K. Recipes can vary by country, so check the package you’re buying and use the local Coca-Cola product information as a comparison.
If you have PKU, heed the phenylalanine warning on products containing aspartame. And remember: agency intake limits give safety context, not a personal target.