Sweetener acesulfame K, safety confirmed by EFSA

The eante acesulfame K – also known as acesulfame potassium, acesulfame potassium or Ace-K – has been the subject of recent scientific renewal: the European Food Safety Authority (EFSA) issued on 30 April 2025 its latest assessment on this additive (identified as E 950) and concluded that it does not pose a health risk.

What is acesulfame K sweetener?

Discovered accidentally in 1967 by chemist Karl Clauss at Hoechst AG (now Nutrinova), acesulfame K is a non-caloric artificial sweetener with approximately 200 times the sweetening power of sugar (sucrose). It is a white crystalline powder, stable to heat and to acidic or basic pH, which makes it particularly useful in cooked foods, baked goods and hot beverages.

Chemically, it is the potassium salt of the compound 6-methyl-1,2,3-oxathiazine-4-one and has a molecular formula of C₄H₄KO₄NS. As it is excreted almost entirely in the urine, it is even used as a marker in water contamination studies.

The history of its regulation is as follows:

• Approval in Europe: since the early 1980s, thanks to several studies and evaluations (SCF in 1991, EFSA in 2000).

• Approval in the USin 1988 by the FDA.

• Global use: present in low-calorie soft drinks, sweets, desserts, ice cream, protein supplements, liquid and chewable medicines, among others.

Recent safety assessment: EFSA 2025

The April 2025 evaluation was part of a pre-2009 re-evaluation programme of additives (EU Regulation 257/2010). The main findings were:

1. No genotoxicity: there are no indications that acesulfame K or its degradation products damage DNA.

2. Completeness of review: all authorisations, previous studies and recent scientific evidence were reviewed.

3. ADI update: EFSA increased the Acceptable Daily Intake (ADI) from 9 mg/kg to 15 mg/kg bw/day, based on a NOAEL of 1,500 mg/kg bw/day.

4. Consumer exposure: even the highest intake estimates are below the new ADI limit.

In addition, EFSA proposed to revise the technical specifications of the sweetener, including purity and trace limits for contaminants such as lead and mercury, as well as the inclusion of the CAS number 55589-62-3.

A look at other sugar substitutes shows that:

• The sweeteners acesulfame K and aspartame are equivalent in sweetness (~200× sugar). Sucralose is slightly less sweet (~150×) but also heat resistant. .

• Unlike aspartame, acesulfame K resists cooking and intense heat well.

• It does not cause caries, as it is not fermentable by oral bacteria.

• It is often used in synergistic mixtures to mask bitter flavours.

Conclusion

The sweetener acesulfame K has recently been reaffirmed as safe for use by EFSA in its April 2025 edition, following a comprehensive review of its toxicological profile, history of use and new scientific data. With an ADI increased to 15 mg/kg, it remains a useful tool in sugar reduction, weight control, dental health and the formulation of versatile food products. Although already authorised since the 1980s, this re-evaluation brings additional safety to consumers, health professionals and the food industry.