E950

Acesulfame K (Ace-K)

Last reviewed: 11 May 2026

Heat-stable, zero-calorie sweetener used across UK diet drinks and chewing gum.

What it is

E950 is acesulfame potassium, a synthetic zero-calorie sweetener discovered in 1967 and approved in the EU from 1983. It's a potassium salt of an oxathiazinone dioxide compound — chemistry not present in nature.

• About 200 times sweeter than sucrose
• Zero calories — passes through the body largely unchanged
• Heat-stable; works in baking, pasteurisation and long-shelf-life products
• Slightly bitter aftertaste, almost always co-formulated with another sweetener

Where you'll see it on a UK label

Drinks

• Diet soft drinks (often paired with aspartame in Coke Zero, Pepsi Max and similar)
• Sugar-free energy drinks
• Flavoured waters, sugar-free squash and cordials
• Protein shakes and meal-replacement drinks

Foods

• Sugar-free chewing gum and mints
• Reduced-sugar yoghurts and dairy desserts
• Reduced-calorie ice cream
• Protein bars
• Reduced-sugar jams and preserves

Table-top sweeteners

• Hermesetas (contains acesulfame K + saccharin)
• Supermarket own-brand blends

Non-food

• Toothpaste, mouthwash, chewable vitamins, liquid medicines

What the science shows

Long-term human data

Acesulfame K has a thinner evidence base than aspartame or saccharin. EFSA's most recent review (in progress at the time of writing) is examining acesulfame K alongside other non-nutritive sweeteners as part of a broader programme. Most of the toxicology dossier dates from the 1970s and 1980s. Long-term human cohort data are limited compared with the older sweeteners — that's the honest gap, not a verdict.

Cancer and DNA damage

The published animal studies submitted for approval did not show consistent tumour findings, and EFSA's most recent published opinion did not identify a cancer signal. Independent re-analyses have argued the dataset is older and smaller than ideal. No specific human cancer signal has been identified to date.

Gut bacteria and metabolism

Animal and small human studies have reported microbiome shifts with acesulfame K consumption, and one line of research has looked at whether this might affect glucose tolerance. As with other artificial sweeteners, the clinical significance is unsettled and the human data are short-term.

Potassium content

Acesulfame K contains potassium. The amounts in typical food and drink intake are far below dietary thresholds that would matter to healthy kidneys. People on potassium-restricted diets for chronic kidney disease should be aware of the contribution but it's usually trivial next to dietary potassium from food.

Regulatory status

UK/EU: Approved (E950). ADI 9mg/kg body weight per day (EFSA).

US: FDA approved for drinks (1988) and general food use (2003).

Wider: Approved in 90+ countries.

Reading a UK label

Look for "acesulfame K", "acesulfame potassium", "Ace-K" or E950 in the ingredient list. It's rarely the only sweetener — if you spot it in a diet drink it's almost always paired with aspartame or sucralose. The 9mg/kg ADI for a 70kg adult is 630mg per day, well above any plausible everyday intake from soft drinks (a 330ml diet cola typically contains less than 50mg).

Last updated: 11 May 2026