Aspartame is a popular non-nutritive sweeteners. Chances are good that you or someone you know has had a drink containing an aspartame-based substance within the past 24 hours.

A 2017 study found that in a sample of nearly 17,000 Americans, about 25 percent of children and roughly 41 percent of adults self-reported eating or drinking a food or beverage containing NNS, including but not limited to aspartame.

While aspartame remains popular, it’s also faced controversy in recent years. Many opponents have claimed that consuming aspartame has negative side effects. There are also negative claims about long-term side effects of ingesting aspartame.

The brand names Equal and NutraSweet are used for Aspartame. It is also used in many packaged products, including those labeled as ” diet,” “sugar-free,” or “low- or zero-sugar.”

Aspartame is an odorless powder that is white and is approximately 200 times sweeter than sugar. This means that a very small amount is needed to give foods and beverages a sweet flavor.

The ingredients of aspartame are aspartic acid and phenylalanine. Both are naturally occurring amino acids — also know as the “building blocks” of proteins. Aspartic acid is produced naturally by your body, and phenylalanine is an essential amino acid that you get from food.

How is aspartame broken down in the body?

When your body processes aspartame, part of it is broken down into methanol. Consumption of fruit, fruit juice, fermented beverages, and some vegetables also contain or result in methanol production.

A 2015 study suggests that aspartame was the largest source of methanol in the American diet. Methanol is toxic in large quantities, yet smaller amounts may also be concerning when combined with free methanol because of enhanced absorption.

Free methanol is present in some foods and is also created when aspartame is heated. Free methanol consumed regularly may be a problem because it breaks down into formaldehyde, a known carcinogen and neurotoxin, in the body.

Scientists and regulatory groups caution against making generalizations about the relationship between intake of aspartame, methanol and formaldehyde and health consequences.

For example, the European Food Safety Authority (The European Financial Stability Facility, known as the EFSA.) and Food and Drug Administration (The FDA.) note that that dietary exposure to methanol and formaldehyde produced from ingesting aspartame does not pose a safety concern.

Other researchers note that consuming tomato juice could result in a 6 times greater methanol production than the aspartame used in zero sugar drink.s.

One of the most thorough studies of NNS is Aspartame. A number of regulatory agencies have confirmed that the products are safe for use in the general population, including infants, children and people who are pregnant or lactating.

Many health-related organizations say that there is no evidence that aspartame has any adverse effects.

In 2013, The European Financial Stability Facility, known as the EFSA. was asked to re-evaluate the safety of aspartame, conducting a review of more than 600 datasets from aspartame studies. It found no reason to remove aspartame from the market.

The review reported no safety concerns associated with normal or increased intake. However, a 2019 paper and 2020 paper from the same research group, as well as letter to the editor published in 2020 in the journal Archives of Public Health, question The European Financial Stability Facility, known as the EFSA.’s conclusions on the safety of aspartame.

The Scientific Report of the 2015 Dietary Guidelines Advisory Committee also recently reviewed the evidence on aspartame safety ahead of submitting their report to the U.S. Department of Agriculture, and U.S. Department of Health and Human Services (HHS), to provide information for the 2015-2020 Dietary Guidelines for Americans.

The committee agreed with The European Financial Stability Facility, known as the EFSA.’s conclusions on aspartame safety for the general population.

Acceptable daily intake levels of aspartame

The acceptable daily intake (ADI) is used as an estimate of the amount of aspartame that can be consumed every day over a persons entire lifetime (the general population, including all age ranges and physical conditions) without any adverse health outcomes or side effects.

The ADI recommendations from the The FDA. and The European Financial Stability Facility, known as the EFSA. for aspartame are:

  • The FDA.: 50 milligrams per kilogram of body weight
  • The European Financial Stability Facility, known as the EFSA.: 40 milligrams per kilogram of body weight

To put this into perspective for a person weighing 150 pounds (or 68 kilograms), the below is what would have to be ingested to meet the The FDA. ADI:

When a product is labeled sugar-free, it usually means it has a NNS in place of sugar. One of the most popular sweeteners is aspartame, which is not found in all sugar-free products. It is available in a number of packaged foods.

Some products contain aspartame.

  • zero sugar drink.
  • There is no sugar in ice cream.
  • fruit juice has fewer calories.
  • There is no sugar-free gum.
  • The sugar in the sauce is reduced.
  • Light yogurt.
  • No sugar energy bars.
  • The salad dressing is free of sugar.
  • There is no sugarless candy.

The ingredients panel on the back of the package must be labeled with the name of the product. Some food and beverage manufacturers are removing aspartame from their products.

There have been no conclusive links between Aspartame and health problems in the general population. Products containing aspartame should be avoided for certain people.


People who have a condition called phenylketonuria (PKU) shouldn’t ingest products containing aspartame. PKU is a rare genetic disease diagnosed at birth. People with PKU aren’t able to properly process phenylalanine, so it can accumulate to dangerous levels in the body.

A build-up of phenylalanine in the body can lead to a range of negative side effects, including brain damage.

Phenylalanine is an essential amino acid found in protein sources such as meat, fish, eggs, and dairy products. It’s also one of the two ingredients of aspartame.

People with PKU do not have the ADI and safety approvals for aspartame. Federal labeling regulations require that foods, drinks, and medications containing aspartame have a warning on the ingredients panel to help people with PKU avoid eating it.

Tardive dyskinesia

People who are taking medications for schizophrenia should also avoid aspartame. Tardive dyskinesia (TD) is thought to be a side effect of some schizophrenia medications. The phenylalanine in aspartame may precipitate the uncontrolled muscle movements of TD.


The HHS has noted that some additional populations may have problems with aspartame because their body cannot properly break down phenylalanine, including:

  • People with advanced liver disease.
  • Women with high levels of phenylalanine in their blood are pregnant.

There have been a multitude of claims with varying levels of scientific certainty linking aspartame to many side effects and adverse health outcomes, including but not limited to:

Some research reports an increased risk of disease or acceleration of side effects, while others report no negative outcomes linked with aspartame intake. Consistency on the science related to these claims about aspartame could be complicated by the challenges of how research on NNS is done, interpreted, and reported on.

In fact, a 2019 study commissioned by the World Health Organization looked at the relationship between NNS, including aspartame, and several health outcomes in humans, including:

  • The body weight is what it is.
  • Control of blood sugar.
  • “It’s oral health.”
  • Eating behavior
  • preference for sweet taste
  • cancer
  • cardiovascular disease is a disease.
  • The disease of the kidneys.
  • Mood, behavior, and cognitive function.
  • Other adverse effects.

The researchers did not find significant differences between the groups who took NNS and those who did not, but they did not have confidence in the results.

  • There are too few studies for each health outcome.
  • There are too few research participants.
  • Studies were identified too late.
  • The methodology and reporting was not good.
  • Potential harms could not be excluded.

Given such inconsistency in the scientific literature, and the limited amount of high-quality studies done to-date on any of these health conditions or side effects, research is ongoing to explore if aspartame is linked conclusively and with a strong level of scientific certainty to any of these reported negative outcomes.

Despite aspartame’s widely accepted safety record, many scientists are calling for additional research on the side effects and health outcomes of its ingestion over long-term periods of time, across all life stages, and within different settings.

Natural NNS alternatives exist if you want to avoid products containing aspartame. You may want to look for products that are sweetened.

These alternatives are still natural and should be consumed in moderation.

Aspartame is one of the most researched substances in the food supply with hundreds of studies completed to date.

Despite the unanimous approval of global regulatory agencies and health organizations that the use of aspartame is safe and has minimal health risks for the general population, there is still concern about the effects on the body.

Some people and population groups may benefit from using aspartame to control calories and sugar intake in moderation. There is more research needed to explore the effects of long-term exposure to aspartame.

If you are instructed by a doctor to manage your phenylalanine intake, you should avoid all products containing aspartame. There are many alternatives to NNS.

If you want to avoid products with aspartame for personal preference, you should thoroughly review the ingredients panel and choose foods or drinks that are free of the substance.