Artificial sweeteners explained: aspartame, sucralose, stevia and more

Artificial sweeteners are generally considered safe in the amounts people normally eat: every approved sweetener has an acceptable daily intake set well below the level that caused any effect in studies. They are not a health food, though. WHO advises against using them for weight control, and aspartame was classed as "possibly carcinogenic" in 2023 on limited evidence, without a change to its safe intake.

Types of sweeteners and their E-numbers

Sweeteners fall into two families. Intense sweeteners are hundreds or thousands of times sweeter than sugar, so tiny amounts are used and they add almost no calories. Sugar alcohols (polyols) are less sweet than sugar, are used in larger amounts and still provide some calories.

Sweeteners are food additives, so in Europe they appear in the ingredient list by name or E-number, after the word "sweetener". For more on how additives are labeled, see E-numbers explained.

How sweeteners are regulated: acceptable daily intake

Before a sweetener is approved, regulators such as the European Food Safety Authority (EFSA), the US FDA and the WHO and FAO expert committee (JECFA) review the safety studies. They set an acceptable daily intake (ADI): the amount per kilogram of body weight that a person can consume every day over a lifetime without appreciable risk. It is normally set at a hundredth of the highest dose that showed no adverse effect in studies.

For aspartame, JECFA and EFSA use an ADI of 40 mg per kg of body weight per day, and the FDA uses 50 mg. For sucralose, the FDA's ADI is 5 mg per kg, and for steviol glycosides it is 4 mg per kg expressed as steviol. Values can differ between agencies, and regulators re-evaluate sweeteners as new data arrive.

Is aspartame safe? The 2023 evaluations

In July 2023, two WHO bodies published their reviews of aspartame on the same day. The International Agency for Research on Cancer (IARC) classified it as possibly carcinogenic to humans (Group 2B), based on limited evidence for liver cancer in humans. IARC's categories describe how strong the evidence is that something could cause cancer, not how likely it is to do so at normal doses.

JECFA, which assesses risk at real-world doses, kept the ADI at 0 to 40 mg per kg and confirmed that daily intake within it is safe. WHO gave an example: an adult weighing 70 kg would need to drink more than 9 to 14 cans of diet soft drink a day, each containing 200 to 300 mg of aspartame, to exceed the ADI, with no other sources. Both bodies called for more research.

Are artificial sweeteners bad for weight and health?

Swapping sugary drinks for sugar-free ones cuts sugar and calories in the short term. But in May 2023, WHO published a guideline recommending against using non-sugar sweeteners to control body weight or to lower the risk of diseases such as heart disease. Its review found no long-term benefit for body fat in adults or children, and some observational studies linked long-term use to a higher risk of type 2 diabetes, cardiovascular disease and death in adults.

WHO rated the recommendation as conditional, because those links may be explained by other differences between people who use sweeteners and those who do not. It does not apply to people who already have diabetes, to toothpaste, skin creams or medicines, or to sugar alcohols. The Dietary Guidelines for Americans 2025 to 2030, released in January 2026, go in the same direction, saying that neither added sugars nor non-nutritive sweeteners are recommended as part of a healthy diet.

The practical message: a diet drink is a better choice than a sugary one, but water is better than both. Our guide on how much sugar per day is too much helps you cut sugar without relying on sweeteners.

Stevia vs sugar: is natural better?

Stevia sweeteners are made from purified steviol glycosides extracted from the leaves of the stevia plant. They have no calories and do not raise blood sugar. In the US, only highly purified extracts are permitted; whole stevia leaves and crude extracts are not approved as sweeteners.

"Natural" does not mean exempt from the same questions, though. WHO's guideline covers stevia too, and many stevia products are blended with erythritol or other sweeteners, so read the ingredient list. Monk fruit (luo han guo) extract is another plant-based sweetener used in the US.

Erythritol and sugar alcohols

Sugar alcohols such as sorbitol, xylitol, maltitol and erythritol are found in sugar-free gum, mints, chocolate and "keto" products. They do not cause tooth decay and raise blood sugar less than sugar does. Because they are only partly absorbed, large amounts can cause gas, bloating or diarrhea. In the EU, foods with more than 10% added polyols must warn that excessive consumption may produce laxative effects.

Erythritol has drawn attention since a 2023 observational study linked higher blood levels of it to heart attack and stroke. The FDA reviewed this research and said the observational studies did not establish a causal link, but the question is still being studied.

Sweetened snacks and drinks are often ultra-processed too, so if you want to cut back, see how to choose a healthy snack.