What is E950?
Acesulphame potassium (Ace K) — a zero-calorie artificial sweetener around 200 times sweeter than sugar, and a regular finding in recent large-scale cancer-risk research.
E950 is acesulphame potassium, a synthetic sweetener with no calories that passes through the body largely unchanged rather than being metabolised. It's approved for use in Australia, the US and the EU, but a 2022 study following over 100,000 French adults found a statistically significant association between higher intake and increased cancer risk. Goodnessly rates it Avoid.
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What is acesulphame potassium?
Acesulphame potassium is a synthetic sweetener first developed by German chemists in the late 1960s. Unlike sugar, or even aspartame, it isn't broken down by the body — it's absorbed and then passed unchanged through urine. It's often blended with other sweeteners like aspartame or sucralose, partly because it can leave a slightly bitter aftertaste on its own, and combining sweeteners lets manufacturers use less of each.
What's it used for?
- Sweetening diet and "zero" soft drinks without adding calories
- Sugar-free lollies, chewing gum and confectionery
- Tabletop sweetener products
- Low-calorie desserts, yoghurts and baked goods
- Often blended with aspartame or sucralose to balance the aftertaste
Where you'll find 950 on the shelf
Almost anywhere sugar has been removed, acesulphame potassium tends to show up in its place.
Is acesulphame potassium safe? What the research says
Ace K has been approved for decades, but its original safety testing has been questioned, and more recent large-scale research has renewed the debate. Here's where regulators currently stand:
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted | Must be declared by name or number (950) on the ingredient list. No additional warning label required. |
| EU European Union (EFSA) | Permitted, ADI raised in 2025 | Listed as E950. EFSA's 2025 re-evaluation raised the Acceptable Daily Intake from 9 to 15mg per kilogram of bodyweight per day — but the same review found lead and mercury levels in commercial samples exceeding EU limits, and flagged an unregulated degradation product with no existing safety limit. |
| US United States (FDA) | Approved | Approved as a general-purpose sweetener, with the same 15mg/kg/day ADI. The original 1970s animal safety studies behind this approval have been criticised by public health researchers as too limited by modern standards. |
Acesulphame potassium isn't metabolised by the body the way sugar or even aspartame is — it's absorbed and excreted largely unchanged, which is part of why it has no calories, but also means it circulates through the body intact rather than being broken down.
- 2022 NutriNet-Santé cancer study: published in PLOS Medicine (Debras et al., 2022), this study followed 102,865 French adults for a median of 7.8 years and found higher acesulphame-K intake was associated with a statistically significant increase in overall cancer risk (hazard ratio 1.13, 95% CI 1.01–1.26, p=0.007). Aspartame showed a similar association; sucralose did not. As an observational study, it shows a correlation rather than proving the sweetener causes cancer, but the finding was strong enough to be cited by EFSA in its ongoing re-evaluation of sweeteners.
- EFSA's 2025 re-evaluation raised the ADI, but also flagged contamination: alongside raising the daily intake limit, EFSA's own review found commercial samples of E950 exceeding EU limits for lead and mercury, and identified an impurity (acetylacetamide) that currently has no regulatory limit at all.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Who might want to limit or avoid it
- Anyone who regularly drinks diet or zero-sugar soft drinks, a major source of acesulphame-K intake
- People choosing artificial sweeteners specifically to manage cancer risk factors, given the 2022 findings run somewhat counter to that goal
- Pregnant people and children, who are often advised to moderate artificial sweetener intake generally as a precaution while research continues
- Anyone who prefers to wait for EFSA's ongoing sweetener re-evaluation to conclude before drawing firm conclusions either way
Goodnessly rates E950 Avoid. It remains legally approved in Australia, the US and the EU, but the combination of thin original safety testing, a significant association with cancer risk in a large 2022 cohort study, and EFSA's own 2025 review flagging contamination issues in commercial samples places it in our highest-caution category.
How to spot it on a label
Acesulphame potassium is required to be declared clearly. Look out for:
- Acesulphame potassium
- Acesulfame K / Ace K
- 950 or E950
- "Sweetener (950)" in the ingredients list
Diet soft drinks, sugar-free confectionery and tabletop sweeteners are the most common places to find it — often listed alongside aspartame or sucralose.
Related additives
Frequently asked questions
Is E950 the same as Ace K?
Yes — 950 (or E950) is the additive code for acesulphame potassium, also called acesulfame K or Ace K. All three names refer to the same synthetic sweetener.
Is acesulphame potassium banned anywhere?
No. It remains legally approved in Australia, New Zealand, the US and the EU. The EU actually raised its Acceptable Daily Intake in 2025 following a fresh review, though that same review also flagged contamination issues in commercial samples.
Does acesulphame potassium cause cancer?
A 2022 study following 102,865 French adults for a median of 7.8 years found a statistically significant association between higher acesulphame-K intake and increased overall cancer risk. This is an observational study, which can show a correlation without proving the sweetener causes cancer, but the finding was strong enough to be cited in the EU's own ongoing re-evaluation of sweeteners.
Does Goodnessly rate E950 as safe, caution, or avoid?
Goodnessly rates E950 (Acesulphame Potassium) as Avoid. While it remains legally approved, the combination of thin original safety testing, a significant cancer-risk association in a large 2022 cohort study, and contamination concerns raised in the EU's own 2025 review place it in our highest-caution category.
Is acesulphame potassium metabolised by the body?
No. Unlike sugar, and unlike aspartame, acesulphame potassium isn't broken down during digestion. It's absorbed and then excreted largely unchanged through urine, which is part of why it contributes no calories.
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