Which Artificial Sweetener is the Safest?

By Published On: September 26, 2019Last Updated: November 23, 2022

With artificial sweeteners like aspartame and Ace K commonly used as sugar substitutes, we can indulge in our favorite snacks while keeping our calorie intake in check. However, questions persist about their effects on our health. We look at what science has to say about the safety of artificial sweeteners.

Current (2022) scientific evidence supports the safety of all six artificial sweeteners currently on the market (sucralose, aspartame, acesulfame potassium, saccharin, neotame and advantame). Over 50 years of clinical data show that consuming artificial sweeteners has no adverse health effects in the short and long term. Despite this, many people still link them to diseases like cancer and diabetes.

Why Sugar is a Problem

What Causes Obesity?

Since the 1970s, obesity rates all around the world have been rising. Naturally, people first blamed our increased fat consumption in our diet for getting fat. Health agencies quickly declared that fat was the apparent culprit, so people began to reduce their intake of fatty foods. Despite this, obesity rates worldwide continue to increase1.

We now know that eating fatty foods doesn’t cause weight gain. Instead, we create the fat in our bodies after consuming excess energy. The amount of energy in food is measured in the number of calories.

Fat is a ‘long-term’ storage of energy; an investment our bodies make for when we need it later. If we don’t immediately use the calories we consume, our body is more than happy to store them as fat.

Unfortunately, the lifestyle we lead today involves consuming much more calories than we burn, mostly in the form of sugar.

Low Fat, High Sugar

Sugar is everywhere! Most products on supermarket shelves are high in sugar, contributing to our excess calorie intake and leading to weight gain and obesity. Many ‘low-fat’ variants of food products are incredibly high in carbohydrates and added table sugar (sucrose), making them a misleading source of calories.

Take the example below of a ‘low fat’ yogurt containing 10 g of carbohydrates and 7 g of sucrose, contributing to 60 kcal per 100 ml. To put that into context, the same amount of Coca-Cola has fewer calories (39 kcal per 100 ml)!

low fat high sugar yogurt sucrose

Our Love for Sugar

Sugar is copiously added by to food products because 1) it’s cheap and 2) it tastes good.

Humans love the taste of sugar due to our evolutionary history, where the search for energy-dense food was key to survival. Today, products are intentionally packed with sugar, with their high energy content causes rising obesity rates and related diseases like heart disease and diabetes.

Luckily, consumers like us are becoming more health conscious, opting for sugar alternatives or sugarless versions of our favorite products. Artificial sweeteners can satisfy our desire to lead healthy lifestyles and our evolutionary sweet tooth, making them an ideal replacement for sugar.

Evaluating Several Artificial Sweeteners

There are currently six artificial sweeteners approved for use in food products: sucralose, aspartame, acesulfame potassium, saccharin, neotame and advantame. They have all been reviewed to be safe for consumption, with studies continuously supporting their lack of negative long-term health effects.

They are commonly used as sugar substitutes in candy, soft drinks and cereals, among other products. Below is a safety evaluation of the scientific data available for the top three most common: sucralose, aspartame and acesulfame potassium.


Sucralose was accidentally discovered at British food supplier Tate & Lyle in 1976 when one of their researchers misheard ‘test’ for ‘taste’2. They had been making adjustments to the sugar molecule, hoping that by inserting chlorine atoms into its chemical structure, they could prevent it from being digested as usable calories.

The result was a chemical (structure shown below) hundreds of times sweeter than sugar in addition to being almost noncaloric: the compound just passed through the body without being digested!

Over the next few years, more than 100 scientific studies involving sucralose were conducted in animal and human trials. All of them failed to show any carcinogenic, reproductive or neurological effects, highlighting the safety of the artificial sweetener. By the 1990s, sucralose was approved in various countries for use as a safe and effective artificial sweetener.

sucrose and sucralose chemical structures


Yet another accidental discovery, aspartame, was created at pharmaceutical company G. D. Searle in 1965. A scientist working on a drug that could prevent gastric secretion spilled some of the compound on his hands. In a bout of nonchalance, he went back to work and licked his fingers to help pick up some paper. Surprised by how incredibly sweet the compound was, the scientist licked it again to confirm his discovery3.

The company quickly identified aspartame’s potential as an artificial sweetener. Aspartame, like sucralose, is hundreds of times sweeter than table sugar. It binds to receptors on our tongue and palate that are responsible for sending the taste of ‘sweetness’ to our brains.

Aspartame in our body breaks down into two amino acids that have no caloric value: aspartic acid and phenylalaline (shown below). Both of these are required in our diet to make proteins that help us function.

aspartame chemical structure reaction between aspartic acid and phenylalanine

Since aspartame is broken down into products we naturally need to survive, the chemical must be safe, right? Regulatory agencies still insisted that aspartame be put through clinical trials; over 100 trials worldwide, in fact. In the end, all of them found the artificial sweetener was safe for consumption, with some volunteers even losing weight after replacing the sugar in their diet with aspartame4.

After 30 years of trials (longer than most drug development timelines), the FDA removed all restrictions surrounding using aspartame as a food additive in 1996. However, individuals with phenylketonuria (a genetic disease that makes them unable to process phenylalanine) must avoid aspartame, along with food high in phenylalanine like meat, beans and dairy products.

Acesulfame Potassium (Ace K)

Contrary to what these discoveries might suggest, we chemists aren’t that careless. Unfortunately, acesulfame potassium (or Ace K) was discovered through yet another case of finger-licking, this time by a scientist working at German chemicals company Hoechst AG in 19675.

This fateful lick of sweetness led to the company developing a range of compounds with a similar ring structure, with the sweetest of these being Ace K (shown below). Although having a very different chemical structure compared to sugar, Ace K activates the same taste receptors in our tongue responsible for sweetness.

chemical structure of acesulfame potassium ace K

Ace K is an actual noncaloric sweetener, as our body completely ignores it. It comes out the way it goes in, untouched and unreacted. On the shelf, it is stable over several years. It can also be used in cooking and baking since its chemical structure withstands high temperatures!

With over 20 years of safety data in tow, it was approved as a sugar substitute in 1992 and for use in drinks in 1998. A worldwide review in 2006, 40 years after its discovery, showed no scientific evidence for any long term health issues associated with its consumption6.

Artificial Sweeteners on the Market are Safe

Health Benefits of Artificial Sweeteners

So, which artificial sweetener is the safest? After decades of scientific data across hundreds of clinical trials worldwide, we can conclude that all of the artificial sweeteners on the market are safe.

Due to the intense sweetness of artificial sweeteners, only a tiny amount is needed to elicit the same taste of sweetness as sugar. Furthermore, some sweeteners like sucralose and acesulfame potassium can be considered noncaloric as they don’t interact with the body. This makes them ideal as sugar substitutes (like ‘Equal’), especially for people suffering from diseases like high blood pressure or type 2 diabetes.

For those who want to watch our calorie intake, artificially sweetened desserts, yogurts, jams and syrups, and even baked goods are now commonly found in supermarkets. Sugar-free drinks today often contain a mixture of Ace K and aspartame as, according to tasters, this mix produces a taste closest to table sugar.

equal artificial sweetener sugar substitute aspartame acesulfame K

Sugar Fuels our Bodies, Misinformation Fuels the Media

Since the discovery of artificial sweeteners, many have tried to link their consumption with an increased risk of cancer and other diseases. Predatory medical journals have published several studies with inconclusive results borne out of dishonest reporting of results and shoddy statistics7. This was, of course, picked up by news articles.

For example, a 1996 study stated that rising brain tumor rates over the past 15 years coincided with the approval of aspartame8. In the study, 320 rats were fed aspartame for two years, after which 12 developed brain tumors. The media had a field day, publishing headlines like ‘Increasing brain tumor rates: is there a link to aspartame?’

The scientific community wasn’t so impressed. The study’s authors had fallen victim to confirmation bias, cherry-picking the data to suit their initial theory. Furthermore, later trials involving aspartame-fed rats could not replicate the study’s results.

In 2008, researchers supported by the Sugar Association (a trade group in the sugar industry) reported adverse health effects of sucralose in rats. Sucralose affected intestinal pH and increased the production of cytochrome p450, proteins usually associated with breaking down drugs9. A year later, an expert panel of reputable scientists found the study poorly designed and could not be considered scientific evidence10.

The media is partially to blame for the trigger-happy spreading of misinformation. News outlets are quick to publish sensational and controversial pieces. ‘Acesulfame Potassium Causes Brain Tumors’ is a better headline than ‘Even More Evidence That Artificial Sweeteners Are Safe’.

There are over 50 years of pre-clinical and clinical data to support the safety of artificial sweeteners on the market today. Despite this overwhelming scientific evidence, it is rather absurd that the media can alter the public’s perception of them with just a simple headline, time and time again.


  1. Wright, J. D., Kennedy-Stephenson, J., Wang, C. Y., McDowell, M. A., & Johnson, C. L. (2004). Trends in intake of energy and macronutrients-United States, 1971-2000. JAMA291(10), 1193-1193.
  2. Fraser-Reid, B. (2012). From Sugar to Splenda: A Personal and Scientific Journey of a Carbohydrate Chemist and Expert Witness. Springer Science & Business Media.
  3. Lewis, R. A. (2001). Discovery: Windows on the Life Sciences.
  4. De la Hunty, A., Gibson, S., & Ashwell, M. (2006). A review of the effectiveness of aspartame in helping with weight control. Nutrition Bulletin31(2), 115-128.
  5. Newton, D. E. (2007). Food Chemistry (New Chemistry).
  6. Magnuson, B. A., Burdock, G., Doull, J., Kroes, R. M., Marsh, G. M., Pariza, M. W., … & Williams, G. M. (2007). Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies. Critical reviews in toxicology37(8), 629-727.
  7. Weihrauch, M. R., & Diehl, V. (2004). Artificial sweeteners – do they bear a carcinogenic risk?. Annals of Oncology15(10), 1460-1465. ‘
  8. Olney, J. W., Farber, N. B., Spitznagel, E., & Robins, L. N. (1996). Increasing brain tumor rates: is there a link to aspartame?. Journal of Neuropathology & Experimental Neurology55(11), 1115-1123.
  9. Abou-Donia, M. B., El-Masry, E. M., Abdel-Rahman, A. A., McLendon, R. E., & Schiffman, S. S. (2008). Splenda alters gut microflora and increases intestinal p-glycoprotein and cytochrome p-450 in male rats. Journal of Toxicology and Environmental Health, Part A71(21), 1415-1429.
  10. Brusick, D., Borzelleca, J. F., Gallo, M., Williams, G., Kille, J., Hayes, A. W., … & Burks, W. (2009). Expert panel report on a study of Splenda in male rats. Regulatory Toxicology and Pharmacology55(1), 6-12.

About the Author

sean author
Sean Lim

Sean is a consultant for clients in the pharmaceutical industry and is an associate lecturer at La Trobe University, where unfortunate undergrads are subject to his ramblings on chemistry and pharmacology.

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