Acesulfame K – a guide to artificial sweeteners

Acesulfame K (E 950) is a fairly unknown sweetener despite being found in a wide range of known foods, including Coca-Cola Zero. But even though it is 200 times sweeter than sugar, it has a bitter aftertaste.

22 September 2020 •

In our series ‘Guide to arti­fi­cial sweet­en­ers,’ we have come to the anony­mous Acesulfame K. It is con­sid­ered the new gen­er­a­tion of high-inten­si­ty sweet­en­ers, even though it was invent­ed at the same time as aspar­tame in the 1960s. It is a chem­i­cal sub­stance with a bit­ter after­taste that the body is unable to absorb. What are the ben­e­fits of this sweet­heart, and are there bet­ter alternatives?

Acesulfame K, a chemically produced sweetener

Acesulfame K (E 950) is a chem­i­cal­ly pro­duced sweet­en­er. It was invent­ed in Germany in 1967 and entered dif­fer­ent mar­kets in 1983. It is up to 200 times sweet­er than sug­ar but has a bit­ter after­taste. Therefore, it is often used in com­bi­na­tion with aspar­tame, cycla­mate and sucralose. There are about 300 man­u­fac­tur­ers of Acesulfame K. About 250 of them are locat­ed in China.

An agent with many names

Acesulfame K is an abbre­vi­a­tion for ace­sul­fame potas­si­um. It is also called Ace-K or ACK. In Europe, it has the e-num­ber: E 950.

Its chem­i­cal spec­trum is: ‘6-Methyl-1,2,3-oxathiazin-4(3H)-one 2,2-dioxide potas­si­um salt(55589-62-3) 13C NMR’ and ‘6-Methyl-1,2,3-oxathiazin-4(3H)-one 2,2-dioxide potas­si­um salt(55589-62-3) 1H NMR’. The chem­i­cal form is C4H4KNO4S.

It is sold under brand names that are much eas­i­er to pro­nounce, name­ly Sunett and Sweet One.

Discovered when a brave chemist licked his fingers

Acesulfame K was dis­cov­ered by chance in 1967 by the chemist Karl Clauss who worked at Hoechst AG. Karl Clauss tried to cre­ate a reac­tion between 2-Butyn and flu­o­ro­sul­fonyl iso­cyanate. Modern chemists describe it as ‘brave’ to exper­i­ment with two such reac­tive sub­stances, and dur­ing the work, he licked his fin­ger to rub away some white pow­der that was stuck to his shirt. He dis­cov­ered that the fin­ger tast­ed sweet.

What he dis­cov­ered was a chem­i­cal cat­e­go­ry that goes by the name dihy­dro-oxazines from which var­i­ous sweet com­pounds can be found. After fur­ther exper­i­ments, ace­sul­fame was con­tin­ued in com­bi­na­tion with potas­si­um acetate.

The anec­dote about the dis­cov­ery of Acesulfame K is sim­i­lar to the dis­cov­ery of aspar­tame. There are dif­fer­ent ver­sions of who licked what. We can only state that the 60s was a decade when peo­ple enjoyed exper­i­ment­ing with dif­fer­ent chem­i­cals and lick­ing fingers.

powder on fingers

How to make Acesulfame K?

Simply put, it goes like this:

Acesulfame potas­si­um is syn­thet­i­cal­ly pro­duced from ace­toacetic acid and flu­o­ro­sul­fonyl iso­cyanate. It forms a com­pound which is con­vert­ed to flu­o­ro­sul­fonyl ace­toacetic acid amide, which is then cyclized (a reac­tion for a part of a mol­e­cule sim­i­lar to anoth­er mol­e­cule to form a closed ring) with potas­si­um hydrox­ide to form an oxathi­azi­none diox­ide ring sys­tem from which extracts potas­si­um acetate.

An alter­na­tive way is to com­bine diketene with sul­fam­ic acid and a dehy­drat­ing agent which removes water by break­ing chem­i­cal com­pounds and thus cre­at­ing a crys­tal­liza­tion which is neu­tral­ized with potas­si­um hydrox­ide where­upon ace­sul­fame potas­si­um is formed.

For those who want in-depth infor­ma­tion about the man­u­fac­tur­ing, we refer to ChemicalBook.


Acesulfame K is used as a sweet­en­er but also as a flavour enhancer that increas­es sweet­ness in aspar­tame, cycla­mate or sucralose. You will find Acesulfame K in prod­ucts as:

    • Juice, soda, ener­gy drinks, alcohol
    • Ice cream
    • Jam
    • Toothpaste
    • Gum
    • Yoghurt and oth­er dairy products
    • Condiments
    • Marinades
    • Cereals

And more.

Accepted daily intake (ADI)

For Acesulfame K, it is rec­om­mend­ed that we stay below 15 mg per kilo­gram per day. (Compare with aspar­tame: 40 mg /​ kg /​ day; sac­cha­rin: 5 mg /​ kg /​ day.) It can be dif­fi­cult to know how much Acesulfame K each prod­uct con­tains because man­u­fac­tur­ers do not have to state the amount.


  • Acesulfame K is up to 200 times sweet­er than sugar.
  • It gives no calories.
  • It is cheap­er than sugar.
  • It can with­stand heat.
  • It is approved as a sweetener.


  • It is a chem­i­cal prod­uct indeed. There is noth­ing ‘nat­ur­al’ about Acesulfame K. This puts Acesulfame K high on lists of ‘dan­ger­ous prod­ucts’ cir­cu­lat­ing on the inter­net, even though rel­e­vant author­i­ties around the world have approved it.
  • The human body can­not break it down. It cir­cu­lates in the blood until it comes out with the urine. This fact con­tributes to the con­no­ta­tion of ‘unnat­ur­al’ sweet­en­er. It also leads to con­cerns about envi­ron­men­tal impact.
  • It has a bit­ter aftertaste.

Is Acesulfame K dangerous?

When han­dling Acesulfame K in pro­duc­tion, you must wear pro­tec­tive cloth­ing, gloves and gog­gles. It can be irri­tat­ing to the skin, eyes and breath­ing. If it comes in con­tact with eyes, rinse them with plen­ty of water and seek med­ical attention.

For food con­sump­tion, it is clas­si­fied as safe. No warn­ing texts are manda­to­ry on pack­ages. According to the FDA (Federal Drug Administration), there are 90 stud­ies that show that Acesulfame K is safe.

Concerns have been raised that it may be car­cino­genic. Critics have called for more stud­ies, but this has been reject­ed by the FDA and the EFSA (European Food Safety Authority). The National Cancer Institute (NCI) has also con­clud­ed that Acesulfame K is harm­less in this regard.

Animal stud­ies indi­cate a poten­tial risk that Acesulfame K may stim­u­late insulin secre­tion and lead to reac­tive hypo­glycemia. These stud­ies have used high­er dos­es of Acesulfame K than rec­om­mend­ed for humans. In recent years, research has shown the enor­mous impor­tance of the intesti­nal flo­ra for our health. In that con­text, arti­fi­cial sweet­en­ers appear as a cause of dis­turbed intesti­nal flo­ra, which can be linked to chron­ic low-inten­si­ty inflam­ma­tion and obe­si­ty. This is an area of research that will become increas­ing­ly impor­tant in the future and worth keep­ing an eye on.


Acesulfame K (E 950) is a high-inten­si­ty sweet­en­er that was dis­cov­ered by a German chemist in 1967 and began to be used in var­i­ous coun­tries in 1983. It has a bit­ter after­taste. Therefore, it is often used in com­bi­na­tion with aspar­tame, cycla­mate or sucralose. The major ‘food agen­cies’ approve it, and 90 stud­ies show that Acesulfame K is safe. In recent years, the impor­tance of the intesti­nal flo­ra for our health has become increas­ing­ly known, and there are indi­ca­tions that syn­thet­ic sweet­en­ers may have a neg­a­tive impact on the intesti­nal flora.

Acesulfame K is a rel­a­tive­ly unknown ingre­di­ent for ordi­nary con­sumers but is per­ceived as far from ‘nat­ur­al’ and often appears in ‘lists of foods we should avoid’. Partly because the body can not absorb ace­sul­fame K but allows it to cir­cu­late in the blood until it comes out the nat­ur­al way.

test tubes

Sweet from nature is an alternative

It is excit­ing to fol­low the devel­op­ment of arti­fi­cial sweet­en­ers. It is incred­i­ble what can be achieved with mod­ern tech­nol­o­gy and chem­i­cal processes.

There are how­ev­er oth­er alter­na­tives that are not arti­fi­cial. These days we have sweet­en­ers of nat­ur­al ori­gin. This includes ste­vi­ol gly­co­sides extract­ed from the sweet­leaf, also known as ste­via.

In 2011, EFSA approved ste­vi­ol gly­co­sides as sweet­en­ers fol­low­ing 20 years of research. The food and bev­er­age indus­try in Europe is increas­ing­ly using ste­via and the glob­al ste­via mar­ket is grow­ing annu­al­ly by more than eight per cent.

Curious about stevia?

Are you curi­ous about ste­via and ste­vi­ol gly­co­sides? We devel­op ste­via extracts for dif­fer­ent types of food. Take a look at our range of ser­vices or con­tact us if you want to know more about how we can help you.

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