What's in Coke Zero vs Coca-Cola? Ingredients and Sugar

Coca-Cola Zero Sugar and Coca-Cola Original both list 34 mg of caffeine per 12 fl oz can. The differences are sugar and sweeteners: Zero Sugar lists 0 calories and 0 g sugar and uses aspartame, acesulfame potassium and stevia extract, while a 12 fl oz can of Original lists 140 calories and 39 g sugar (Open Food Facts) from high fructose corn syrup. This guide sets the label facts side by side and does not rank either drink as healthier or cleaner.

Key takeaways

• Per 12 fl oz can, both list 34 mg of caffeine. Zero Sugar lists 0 calories, 0 g sugar and 40 mg sodium. Original, per Open Food Facts, lists 140 kcal, 39 g sugar and about 45 mg sodium.
• Coca-Cola's Original brand page shows its nutrition panel for a 20 fl oz bottle (240 kcal, 65 g total sugars, 65 g added sugars, 75 mg sodium), so those figures are kept separate from the 12 oz figures.
• Zero Sugar is sweetened with aspartame, acesulfame potassium and stevia extract. Original uses high fructose corn syrup. The Zero Sugar label carries a phenylalanine notice for people with phenylketonuria.
• EFSA's re-evaluation, published September 10, 2026, found no safety concern at the reported uses and use levels for E 950, E 951 and E 962.
• Sweetener amounts and the contents of natural flavors are not disclosed on either product's label.

Side-by-Side at a Glance

The table below uses 12 fl oz can figures for a like-for-like comparison, from Coca-Cola's Zero Sugar page, Coca-Cola's Original page and the Open Food Facts record for the 12 fl oz Original can. Where a value comes from Open Food Facts rather than Coca-Cola, the source is named in the cell.

Per 12 fl oz can: Coca-Cola Zero Sugar	Per 12 fl oz can: Coca-Cola Original
0 calories	140 calories (Open Food Facts)
0 g total sugars	39 g total sugars (Open Food Facts)
40 mg sodium (2% DV)	About 45 mg sodium (Open Food Facts; no DV given for a 12 fl oz can)
34 mg caffeine	34 mg caffeine
Aspartame, acesulfame potassium, stevia extract	High fructose corn syrup
Phenylalanine notice printed on the label	Not disclosed in the listing used here

Coca-Cola's Original brand page shows its nutrition panel for a 20 fl oz bottle, not a 12 oz can. Those 20 oz figures are 240 calories, 65 g total sugars, 65 g added sugars and 75 mg sodium (3% DV). Comparing that bottle panel with the 12 oz Zero Sugar can panel would make the gap look larger than it is on a like-for-like basis.

Coca-Cola Zero Sugar vs Coca-Cola Original: Which Ingredients Are Different?

Both ingredient lists share carbonated water, caramel color, phosphoric acid, natural flavors and caffeine. Original's list adds high fructose corn syrup as its sweetener, and Zero Sugar's list adds several other items. The Original ingredient list in this section comes from Coca-Cola's brand page, not from Open Food Facts, because the Open Food Facts ingredient text for the 12 oz Original can is garbled by OCR.

Shared in both:

• Carbonated water
• Caramel color
• Phosphoric acid
• Natural flavors
• Caffeine

Only in Zero Sugar:

• Aspartame
• Acesulfame potassium
• Stevia extract
• Potassium benzoate (listed as added to protect taste)
• Potassium citrate

Only in Original:

• High fructose corn syrup

Coca-Cola's Zero Sugar page says that when Coca-Cola introduced Coke Zero in 2005, the recipe later evolved into Coca-Cola Zero Sugar. The same page describes a caffeine-free Coke Zero with no sugar, no calories and no caffeine. This article covers the standard caffeinated product only.

Several details are not disclosed on either brand page: what the natural flavors contain, how much phosphoric acid is used, and which high fructose corn syrup type (HFCS 42 or HFCS 55) is used in U.S. Coca-Cola. For a comparison with the diet version, see Coke Zero vs Diet Coke: Ingredients, Taste and Caffeine (34 vs 46 mg).

Coca-Cola Zero Sugar vs Coca-Cola Original: How Much Sugar and Calories Per Can?

How much sugar is in Coke vs Coke Zero?

Open Food Facts lists 39 g of sugars per 12 fl oz can of Coca-Cola Original. Coca-Cola Zero Sugar lists 0 g per 12 fl oz can. The 39 g figure is a total sugars value from Open Food Facts, not a figure printed by Coca-Cola.

The FDA's added sugars guidance cites the Dietary Guidelines for Americans, which recommend limiting added sugars to less than 10 percent of total daily calories. The FDA example for a 2,000 calorie diet is 50 grams of added sugars per day. A 12 fl oz Original can at 39 g of total sugars would be about 78% of that example, but the added sugars amount for the 12 oz can is not disclosed in the listings used here, so the comparison of the can against that example is only approximate.

The 20 fl oz Original bottle panel on Coca-Cola's brand page shows 65 g total sugars and 65 g added sugars. Against the FDA's 50 gram example, that is 130%, which matches the Daily Value line on the brand page.

How many calories are in a can of Coke vs Coke Zero?

A 12 fl oz can of Coca-Cola Zero Sugar has 0 calories on Coca-Cola's brand panel. A 12 fl oz can of Coca-Cola Original has 140 calories according to Open Food Facts. That 140 kcal figure has not been verified against Coca-Cola's own site, so readers who want a manufacturer figure for the 12 oz can should check the can itself.

The 20 fl oz Original bottle panel on Coca-Cola's site lists 240 calories. That number should not be read against the 12 oz can without adjusting for the serving size. The Zero Sugar panel also lists 0 g total carbohydrate, 0 g total sugars and 0 g protein.

Coca-Cola Zero Sugar vs Coca-Cola Original: Is the Caffeine Really the Same?

Does Coke Zero have more caffeine than regular Coke?

No. Coca-Cola's Zero Sugar page states, "Each 12-oz serving contains 34mg of caffeine." Its Original FAQ says a 12-ounce can of Coke has 34 mg, so the two products match on the manufacturer's own figures.

Open Food Facts record 0049000050103 is a listing of Coca-Cola's 2 L product, not a 12 fl oz panel, but it also reads 34 mg per 12 fl oz serving. Caffeine appears in both ingredient lists, so the labels do not show a caffeine gap between these two products.

The FDA has described 400 mg per day as a level for most healthy adults that is not generally associated with negative effects. That figure is a general reference point, not a personal limit. Individual sensitivity varies, and the evidence cited here does not cover how caffeine affects specific health conditions, so those questions are best raised with a clinician.

Coca-Cola Zero Sugar vs Coca-Cola Original: How Do Sodium Levels Compare?

How much sodium is in a can of Coke Zero vs Coke?

A 12 fl oz can of Coca-Cola Zero Sugar lists 40 mg of sodium (2% Daily Value). A 12 fl oz can of Coca-Cola Original lists about 45 mg in Open Food Facts. No Daily Value is given for the Original 12 fl oz can, so the percent comparison is one-sided.

The difference is about 5 mg per can. The two figures come from different sources: Coca-Cola's brand page for Zero Sugar and a third-party database for Original. The Original brand page shows 75 mg sodium (3% DV) for a 20 fl oz bottle, which is a different serving.

Zero Sugar also lists 60 mg potassium (2% DV) per 12 oz can. Sodium is one line on a longer panel, and the label does not show a person's total daily sodium intake. For more on how sodas compare on labels, see The 5 Sodas People Scan Most: Sweeteners, Acids and Colors.

Coca-Cola Zero Sugar vs Coca-Cola Original: What Are the Sweeteners and Are They Safe?

Does Coke Zero have aspartame?

Yes. Coca-Cola's Zero Sugar ingredient list names aspartame, along with acesulfame potassium and stevia extract. Original's ingredient list names none of those three.

The FDA states that aspartame is approved for use in food as a sweetener and is about 200 times sweeter than table sugar. The FDA acceptable daily intake is 50 mg per kilogram of body weight per day. The amount of aspartame in Coca-Cola Zero Sugar is not disclosed.

The FDA describes acesulfame potassium as approved for use in food as a sweetener, about 200 times sweeter than table sugar, and often combined with other sweeteners. It was approved for specific food categories in 1988 and as a general-purpose sweetener in 2003, and the FDA says it reviewed more than 90 studies. The FDA acceptable daily intake is 15 mg per kilogram of body weight per day. The milligrams of acesulfame potassium per can are not disclosed.

Steviol glycosides are reported to be 200 to 400 times sweeter than table sugar. The FDA has not questioned the GRAS conclusions for high-purity steviol glycosides (at least 95% purity), and it states that stevia leaf and crude stevia extracts are not considered GRAS. The Zero Sugar label says stevia extract without naming which glycosides are used. The glycoside identity is not disclosed, and the amount is not disclosed either.

Original is sweetened with high fructose corn syrup. The FDA's question-and-answer page says the proportion of fructose to glucose in HFCS 42 and HFCS 55 is similar to that of sucrose. It also says the FDA is not aware of evidence of a safety difference between foods containing HFCS and foods containing similar amounts of other sweeteners with approximately equal glucose and fructose content, such as sucrose or honey.

Are aspartame and acesulfame potassium still approved?

On September 10, 2026, EFSA published its re-evaluation of the aspartame-acesulfame salt (E 962) and found no safety concern at the reported uses and use levels for E 950, E 951 and E 962. That review reconfirmed the aspartame ADI of 40 mg per kg body weight per day and relied on the recently revised acesulfame K ADI of 15 mg per kg body weight per day.

Regulators do not all agree. The International Agency for Research on Cancer (IARC) placed aspartame in Group 2B, 'possibly carcinogenic', in its July 14, 2023 evaluation. The FDA disagrees with IARC's conclusion and says its scientists do not have safety concerns when aspartame is used under the approved conditions.

Is Coca-Cola Zero Sugar Safe for People with Phenylketonuria, and Who Should Check?

The Zero Sugar label carries the notice PHENYLKETONURICS: CONTAINS PHENYLALANINE, and the FDA says people with phenylketonuria should avoid or restrict aspartame.

The FDA explains that people who have difficulty metabolizing phenylalanine because of PKU should avoid or restrict aspartame, and that products containing aspartame must include a statement informing people with PKU that the product contains phenylalanine. Original's ingredient list does not include aspartame, and no phenylalanine statement appears in the listing used here.

This section is educational, not medical advice. Whether a product fits a particular diet is a question for the person's own healthcare team, especially for people managing PKU or caring for someone who does. The evidence cited here cannot establish how any individual responds to these sweeteners, does not cover every population, and leaves some research questions open.

How to Read the Coca-Cola Zero Sugar and Original Labels Yourself

Match the serving size on both labels before comparing numbers, then check these lines:

• Serving size and container: a 12 fl oz can and a 20 fl oz bottle are different servings.
• Calories and total sugars, and whether an added sugars line appears.
• Sodium, shown in milligrams and as a percent Daily Value.
• Caffeine per serving, which Coca-Cola states on its brand pages for both products.
• Sweetener names in the ingredient list, such as aspartame, acesulfame potassium, stevia extract or high fructose corn syrup.
• Any phenylalanine or PKU statement, which the Zero Sugar label carries.

Aurascan is a food-label scanner that explains each ingredient one by one with cited evidence instead of a single black-box score, pulls product data from Open Food Facts, USDA and barcode databases, and gives per-ingredient verdicts of Clean, Mixed or Flagged. Scan the next can or bottle yourself to see its ingredients and the evidence behind each one.