Artificial sweeteners explained: which ones actually affect people

Artificial sweeteners occupy an odd position. They are among the most heavily tested substances in the food supply, they keep being approved, and a large number of people are still convinced one of them makes them ill.

A regulator asks whether a substance harms people on average. Whether it does something to you is a separate question, so both of those can be true.

Below is what each sweetener is, which ones have a mechanism behind the complaints, and how to find out where you sit.

Two different things get called sweeteners

The label uses one word for two groups that your gut handles differently.

Intense sweeteners are hundreds of times sweeter than sugar, so the amount used is tiny. Aspartame, sucralose, acesulfame K, saccharin, neotame, advantame, cyclamate, and the plant-derived stevia and monk fruit. Most pass through largely unchanged.

Sugar alcohols, the ones ending in -itol, are roughly as sweet as sugar, so they are used in bulk. Sorbitol, maltitol, xylitol, erythritol, isomalt, lactitol, mannitol. These are polyols, they are poorly absorbed by everyone, and they have a well-understood digestive effect covered in high-polyol foods.

If a sugar-free product upsets your stomach, the sugar alcohols are the first place to look and the mechanism is not in doubt.

The full list

Every added sweetener in our database, with its E number where it has one.

Food	Notes
CyclamateE952	Cyclamate (E952) is a sweetener food additive.
SteviaE960	Stevia is a plant-based sweetener. A zero-calorie natural sweetener from stevia leaves.
AspartameE951	Aspartame is an artificial sweetener. A zero-calorie sweetener used in diet drinks.
SucraloseE955	Sucralose is an artificial sweetener. A zero-calorie sweetener 600 times sweeter than sugar.
SorbitolE420	Sorbitol is a sugar alcohol sweetener. A reduced-calorie sweetener used in sugar-free foods.
Monk fruit extract	Monk fruit extract is sweetener from monk fruit. A zero-calorie natural sweetener from Asian melons.
MaltitolE965	Maltitol is a sugar alcohol sweetener. A reduced-calorie sweetener similar to sugar.
GlycerolE422	Glycerol (E422) is a sweetener food additive.
XylitolE967	Xylitol is a sugar alcohol from plants. A low-calorie sweetener that benefits dental health.
Acesulfame potassiumE950	Acesulfame potassium is an artificial sweetener. A zero-calorie sweetener 200 times sweeter than sugar.
SaccharinE954	Saccharin is an artificial sweetener. A zero-calorie sweetener with slight metallic aftertaste.
ErythritolE968	Erythritol is a sugar alcohol sweetener. A zero-calorie sweetener with minimal aftertaste.
NeotameE961	Neotame is an artificial sweetener. A zero-calorie sweetener 8000 times sweeter than sugar.
MannitolE421	Mannitol is a sugar alcohol from plants. A low-calorie sweetener used in sugar-free products.
LactitolE966	Lactitol is a sugar alcohol from lactose. A low-calorie sweetener used in sugar-free foods.
Tagatose	Tagatose is a natural low-calorie sugar. A sweetener with 90% less calories than sugar.
AdvantameE969	Advantame is a high-intensity artificial sweetener. A zero-calorie sweetener 20000 times sweeter than sugar.
IsomaltE953	Isomalt is a sugar alcohol from beet sugar. A low-calorie sweetener used in sugar-free candy.
Allulose	Allulose is a rare natural sugar. A low-calorie sweetener with sugar-like taste.

What the evidence says, sweetener by sweetener

Aspartame. The most studied of all of them. Reviews keep finding no harm at normal intakes. In 2023 the cancer research agency classified it as possibly carcinogenic, and the safety committee left the acceptable daily intake unchanged.¹ Those two bodies rate different things: one rates the strength of evidence, the other rates the dose. It is dangerous for people with phenylketonuria, which is why the label warns about it.

Sucralose. Stable, mostly unabsorbed. The concerns are about the gut microbiome and about what happens when it is heated to baking temperatures, and both are unsettled.

Acesulfame K. Almost always paired with something else, because it is bitter alone. There is little evidence of harm, or of any other effect.

Saccharin. The oldest, and the one with the worst history. The 1970s bladder-cancer finding was in rats by a mechanism that does not occur in humans, and it was removed from the carcinogen list in 2000.²

Stevia and monk fruit. Plant-derived, which sells well and says little about safety. Both are well tolerated by most people; stevia has a liquorice aftertaste some find unpleasant.

The sugar alcohols. The only group with a reliable, dose-dependent effect on ordinary people. Erythritol is the gentlest because the body absorbs and excretes it before gut bacteria can ferment it. Maltitol and sorbitol are the harshest.

Sugar alcohols, intense sweeteners and your symptoms

For digestive symptoms, the sugar alcohols have a clear mechanism and the intense sweeteners mostly do not.

For everything else, headaches and fatigue and the rest, the studies have not found an effect and individual reports keep appearing. A population study can miss something that happens to one person in two hundred, and a personal record answers that kind of question better than a review paper.

How to test it

Sweeteners are easier to test than most additives, because they sit in obvious products: anything sold as diet or sugar-free.

Cut all of them for two weeks, sugar alcohols included, which means reading labels on anything sugar-free or diet. Then reintroduce in two separate arms. Take a sugar alcohol first, since that is where a reaction is most likely, and separately take an intense sweetener such as a diet cola. A few days between each.

If the sugar alcohol arm causes symptoms and the intense sweetener arm does not, you have a polyol problem, and that changes what you can buy.

Journal your day in 30 seconds, find your triggers.

Where Triggerbites fits in

This list comes from the food data inside Triggerbites, where every sweetener is graded by name and by class.

Sweeteners are almost never eaten on purpose. They come inside a drink, a yoghurt or a protein bar, and by the evening nobody remembers which. You journal your day in plain words or by voice, in about 30 seconds: "yoghurt and a coffee for breakfast, a chicken wrap and a Coke Zero for lunch, a protein bar in the afternoon, bloated and gassy all evening." The app finds each product in a catalog of over a million and lists the sweeteners inside it, which the word "diet" on the packet never tells you. Scanning the barcode or photographing the label works too.

After a few weeks the app ranks what your symptoms keep following, including reactions that show up days later. Because it holds each sweetener by class, it can tell you whether a pattern follows the sugar alcohols, the intense sweeteners, or neither, which is the answer the two-arm test is looking for.

Log your day in 30 seconds

Text, voice or photo. Log as you go, or recap it all in the evening.

Your food, broken down

Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.

Everything in the same journal

Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.

See what repeats over time

Patterns between what you eat and how you feel, including delayed reactions that show up days later.

Triggerbites Features

• Log your day in 30 seconds: Text, voice or photo. Log as you go, or recap it all in the evening.
• Your food, broken down: Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.
• Everything in the same journal: Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.
• See what repeats over time: Patterns between what you eat and how you feel, including delayed reactions that show up days later.

Common questions

Which artificial sweetener is most likely to upset my stomach?

A sugar alcohol, one of the ones ending in -itol. Maltitol and sorbitol are the harshest, erythritol the gentlest because the body absorbs and excretes it before gut bacteria can ferment it. The intense sweeteners like aspartame and sucralose have no comparable mechanism.

Is aspartame safe?

Reviews keep finding no harm at normal intakes. In 2023 the cancer research agency classified it as possibly carcinogenic while the safety committee left the acceptable daily intake unchanged, because those two bodies rate different things. It is dangerous for people with phenylketonuria.

Is stevia safer because it comes from a plant?

Plant origin is a marketing point and says little about safety. Stevia is well tolerated by most people, as are several synthetic sweeteners. The main practical difference is the liquorice aftertaste some people dislike.

Why does sugar-free gum have a laxative warning?

Because the sweeteners in it are sugar alcohols, which are poorly absorbed by everyone. They draw water into the bowel and are fermented by gut bacteria. The manufacturers know it, which is why the warning is on the packet.

Do sweeteners affect the gut microbiome?

This is the live question, mostly around sucralose and saccharin, and the studies so far are small or in animals. It is unsettled, so it is worth testing on yourself, and nobody can yet be certain either way.

How do I test whether sweeteners affect me?

Cut all of them for two weeks, then reintroduce in two separate arms: a sugar alcohol first, then an intense sweetener such as a diet cola, with a few days between. If only the sugar alcohol arm causes symptoms, your problem is the polyols.

Live, love, log. 🧡