Artificial sweeteners are chemicals used to sweeten foods and beverages. They taste sweet because they are recognized by the sweetness receptors on your tongue. They provide virtually zero calories, as your body can’t break them down.

Artificial sweeteners are often the topic of heated debate.

On one hand, they’re claimed to increase your risk of cancer and harm your blood sugar and gut health.

On the other hand, most health authorities consider them safe, and many people use them to reduce their sugar intake and lose weight.

This article reviews the evidence on artificial sweeteners and their health effects.

What are artificial sweeteners?

Artificial sweeteners, or sugar substitutes, are chemicals added to some foods and beverages to make them taste sweet.

People often refer to them as “intense sweeteners” because they provide a taste similar to that of table sugar but up to several thousand times sweeter.

Although some sweeteners contain calories, the amount needed to sweeten products is so small that you end up consuming almost no calories (1).

How do artificial sweeteners work?

Many taste buds cover the surface of your tongue, with each taste bud containing several taste receptors that detect different flavors (2).

A perfect fit between a receptor and molecule sends a signal to your brain, allowing you to identify the taste (2).

When you eat, your taste receptors encounter food molecules.

For example, the sugar molecule fits perfectly into your taste receptor for sweetness, allowing your brain to identify the sweet taste.

Artificial sweetener molecules are similar enough to sugar molecules to fit on the sweetness receptor.

However, they are generally too different from sugar for your body to break them down into calories. This is how they provide a sweet taste without the added calories.

Only a minority of artificial sweeteners have a structure that your body can break down into calories. Given that only very small amounts of artificial sweeteners are needed to make foods taste sweet, you consume virtually no calories (3).

Common artificial sweeteners

The following artificial sweeteners are allowed for use in the United States and/or European Union (4):

• Aspartame: Sold under the brand names NutraSweet, Equal, or Sugar Twin, aspartame is 200 times sweeter than table sugar.
• Acesulfame potassium: Also known as acesulfame K, it’s 200 times sweeter than table sugar. It’s suited for cooking and baking and sold under the brand names Sunnet or Sweet One.
• Advantame: This sweetener is 20,000 times sweeter than table sugar and suited for cooking and baking.
• Aspartame-acesulfame salt: Sold under the brand name Twinsweet, it’s 350 times sweeter than table sugar.
• Cyclamate: Cyclamate, which is 50 times sweeter than table sugar, was used for cooking and baking. It has been banned in the United States since 1970.
• Neotame: Sold under the brand name Newtame, this sweetener is 13,000 times sweeter than table sugar and suited for cooking and baking.
• Neohesperidin: It’s 340 times sweeter than table sugar and suited for cooking, baking, and mixing with acidic foods. It is not approved for use in the United States.
• Saccharin: Sold under the brand names Sweet’N Low, Sweet Twin, or Necta Sweet, saccharin is 700 times sweeter than table sugar.
• Sucralose: Sucralose is 600 times sweeter table sugar. It is suited for cooking, baking, and mixing with acidic foods. It’s sold under the brand name Splenda.

Artificial sweeteners, appetite, and weight

Artificial sweeteners are popular among individuals who are trying to lose weight.

However, their effects on appetite and weight vary among studies.

Effects on appetite

Some people believe that artificial sweeteners might increase appetite and promote weight gain (5).

The idea is that artificial sweeteners may be unable to activate the food reward pathway needed to make you feel satisfied after eating (6).

Given that they taste sweet but lack the calories found in other sweet-tasting foods, they’re thought to confuse the brain into still feeling hungry (7, 8).

Additionally, some scientists think you’d need to eat more of an artificially sweetened food, compared with the sugar-sweetened version, to feel full.

Some research even suggests that sweeteners may cause cravings for sugary foods (5, 9, 10, 11).

That said, many recent studies do not support the idea that artificial sweeteners increase hunger or calorie intake (12, 13).

In fact, several studies have found that participants report less hunger and consume fewer calories when they replace sugary foods and beverages with artificially sweetened alternatives (14, 15, 16, 17, 18).

Effects on weight

Regarding weight management, some observational studies report a link between consuming artificially sweetened beverages and obesity (19, 20).

However, randomized controlled studies — the gold standard in scientific research — report that artificial sweeteners may reduce body weight, fat mass, and waist circumference (21, 22).

These studies also show that replacing regular soft drinks with sugar-free versions can decrease body mass index (BMI) by up to 1.3 to 1.7 points (23, 24).

What’s more, choosing artificially sweetened foods instead of those with added sugar may reduce the number of daily calories you consume.

Various studies ranging from 4 weeks to 40 months show that this may lead to weight loss of up to 2.9 pounds (1.3 kg) (13, 25, 26).

Artificially sweetened drinks can be an easy alternative for those who regularly consume soft drinks and want to decrease their sugar consumption.

However, opting for diet soda will not lead to any weight loss if you compensate by eating larger portions or extra sweets. If diet soda increases your cravings for sweets, sticking to water might be best (27).

Artificial sweeteners and diabetes

People with diabetes may benefit from choosing artificial sweeteners, as they offer a sweet taste without the accompanying rise in blood sugar levels (18, 28, 29).

However, some studies report that drinking diet soda is associated with a 6% to 121% greater risk of developing diabetes (30, 31, 32).

This may seem contradictory, but it’s important to note that all of the studies were observational. They didn’t prove that artificial sweeteners cause diabetes, only that people likely to develop type 2 diabetes also like to drink diet soda.

On the other hand, many controlled studies show that artificial sweeteners do not affect blood sugar or insulin levels (33, 34, 35, 36, 37, 38).

Thus far, only one small study found a negative effect.

Women who drank an artificially sweetened drink before consuming a sugary drink had 14% higher blood sugar levels and 20% higher insulin levels, compared with those who drank water before consuming a sugary drink (39).

However, the participants weren’t used to drinking artificially sweetened drinks, which may partially explain the results. What’s more, artificial sweeteners may have different effects depending on people’s age or genetic background (39).

For example, research shows that replacing sugar-sweetened beverages with artificially sweetened ones produced stronger effects among Hispanic youth (40).

Although research results have not been unanimous, the current evidence is generally in favor of artificial sweetener use among those with diabetes. Still, more research is needed to evaluate their long-term effects in different populations (41, 42, 43).

Artificial sweeteners and metabolic syndrome

Metabolic syndrome refers to a cluster of medical conditions, including high blood pressure, high blood sugar, excess belly fat, and abnormal cholesterol levels.

These conditions increase your risk of chronic diseases, such as stroke, heart disease, and type 2 diabetes.

Some studies found both regular and diet soda drinkers have a higher risk of metabolic syndrome (44).

However, other studies report that diet soda either has no effect or a protective one (45, 46, 47).

A 2023 review concluded that artificial sweeteners are associated with hypertension, insulin resistance, high blood sugar, abdominal obesity, and dyslipidemia (48).

Further high quality research is needed to verify the benefits and risks of these products.

Artificial sweeteners and gut health

Your gut bacteria play an important role in your health, and poor gut health is linked to numerous problems.

These include weight gain, poor blood sugar control, metabolic syndrome, a weakened immune system, and disrupted sleep, according to both human and animal studies (49, 50, 51).

The composition and function of gut bacteria vary by individual and are affected by what you eat, including certain artificial sweeteners (52).

One 2019 review of animal studies found that saccharin and sucralose were both shown to decrease healthy gut bacteria (53).

On the other hand, a 2023 review of randomized controlled studies saw no significant change in gut microbiota following the ingestion of artificial sweeteners (54).

Although interesting, more studies in humans are needed before strong conclusions can be made.

Artificial sweeteners and cancer

Since the 1970s, debate about whether there is a link between artificial sweeteners and cancer risk has raged.

It was ignited when animal studies found an increased risk of bladder cancer in mice fed extremely high amounts of saccharin and cyclamate (55).

However, mice metabolize saccharin differently than humans.

Since then, a 2007 study followed 9,000 participants for 13 years and analyzed their artificial sweetener intake. After accounting for other factors, researchers found no link between artificial sweeteners and the risk of developing various types of cancer (56).

Furthermore, a 2015 review of studies published over an 11-year period did not find a link between cancer risk and artificial sweetener consumption (57).

Cyclamate was banned for use in the United States after the original mouse bladder cancer study was published in 1970.

Since then, extensive studies in animals have failed to show a cancer link. However, cyclamate was never re-approved for use in the United States.

Meanwhile, a large 2022 cohort study with 102,865 French adults concluded that saccharin and acesulfame-K were associated with an increase in cancer risk (58).

However, the World Health Organization (WHO), while acknowledging some limited studies linking aspartame to cancer risk, has concluded the evidence is insufficient for them to label it unsafe at this time, calling for further research (59).

Artificial sweeteners and dental health

Dental cavities — also known as caries or tooth decay — occur when the bacteria in your mouth ferment sugar. Acid is produced, which can damage tooth enamel.

Unlike sugars, artificial sweeteners do not react with the bacteria in your mouth. This means they do not form acids or cause tooth decay (60).

Research also shows that sucralose is less likely to cause tooth decay than sugar.

For this reason, the Food and Drug Administration (FDA) allows products containing sucralose to claim that they reduce tooth decay (60, 61).

A 2018 review has concluded that xylitol decreases plaque formation and inhibits bacterial adherence and growth in the teeth (62).

The European Food Safety Authority (EFSA) states that all artificial sweeteners, when consumed in place of sugar, neutralize acid and help prevent tooth decay (28).

Aspartame, headaches, depression, and seizures

Some artificial sweeteners may cause unpleasant symptoms, such as headaches, depression, and seizures in some individuals.

Most studies find no link between aspartame and headaches (63).

However, a 2021 review concludes that aspartame is associated with mood disorders, mental stress, and depression, and long-term consumption may cause neurodegeneration and possibly impair learning and memory. Clearly, more conclusive research is called for (64).

Safety and side effects

Artificial sweeteners are generally considered safe for human consumption (3).

They are carefully tested and regulated by U.S. and international authorities to make sure they are safe to eat and drink.

That said, some people should avoid consuming them.

For example, individuals with the rare metabolic disorder phenylketonuria (PKU) cannot metabolize the amino acid phenylalanine, which is found in aspartame. Thus, those with PKU should avoid aspartame.

What’s more, some people are allergic to sulfonamides — the class of compounds to which saccharin belongs. For them, saccharin may lead to breathing difficulties, rashes, or diarrhea.

Additionally, growing evidence indicates certain artificial sweeteners like sucralose reduce insulin sensitivity and affect gut bacteria (65, 66).

The WHO issued new guidelines in 2023, recommending people not to rely on artificial sweeteners for weight loss and concluding that artificial sweeteners do not contribute enough to body fat reduction in the long term to justify the potential risks (67).

The bottom line

Overall, the use of artificial sweeteners poses few risks and may even have benefits for weight loss, blood sugar management, and dental health.

These sweeteners are especially beneficial if you use them to decrease the amount of added sugar in your diet.

That said, the likelihood of negative effects can vary by individual and depend on the type of artificial sweetener consumed.

Some people may feel bad or experience negative effects after consuming artificial sweeteners, even though they are safe and well tolerated by most people.

If you’d like to avoid artificial sweeteners, try using natural sweeteners instead.