Aspartame Side Effects: Is It Bad for You?

Learn about the side effects of aspartame, where to find it, and what non-calorie sweetener alternatives to consider.

Pouring aspartame in a cup of tea
Kelsey Kunik, RDN
— Signos
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Updated by

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Science-based and reviewed

July 19, 2024
July 3, 2024
— Updated:

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If you turn your bottle of diet soda around and inspect the ingredient list, you’ll likely find aspartame prominently listed. Aspartame is a non-nutritive sweetener, often found in many "sugar-free" and "diet" products. While it helps reduce calorie intake and is approved by the U.S. Food and Drug Administration (FDA) for use as an additive, there has been controversy in the past that this no-calorie sweetener may be linked to serious side effects and health problems.1 In this article, we'll dive deep into what aspartame is, the products that contain it, the potential health risks, including its controversial link to cancer, and provide you with a list of alternative sweeteners to consider.


What Is Aspartame?

Aspartame is a popular artificial sweetener that you’ve probably seen and enjoyed in your favorite diet sodas, sugar-free gums, and other low-calorie or "sugar-free" foods. Other artificial sweeteners like saccharin (Equal or Sweet and Low) and acesulfame (Sunett or Sweet One)  are also often used and seen in these types of foods. You may have also seen aspartame by the brand name Nutrasweet. It's about 200 times sweeter than sugar, so a tiny amount can make things taste sweet without adding calories. This makes it a go-to choice for people trying to cut back on sugar and manage their weight.2

Aspartame is made of two amino acids (the building blocks of protein): aspartic acid and phenylalanine. When you eat foods with aspartame, your body breaks it down into these amino acids and a small amount of methanol, which your body then processes further.2 While aspartame has been a staple in the world of sugar substitutes since the 1980s, it’s had its fair share of controversies, especially when it comes to potential health effects. 

What Products Contain Aspartame?


If you look at any low-calorie, sugar-free, or diet drink or food, you may see aspartame featured on the ingredient list. It’s found in everyday foods and drinks, especially those marketed to people on a weight loss journey or who have type 2 diabetes. While many of these types of foods and drinks use other non-nutritive sweeteners, here are some everyday items that often contain aspartame:

  • Diet soda
  • Juice and iced tea
  • Chewing gum
  • Breath mints
  • Powdered drink mixes
  • Protein shakes
  • Sugar-free syrup
  • Sugar-free candy
  • Flavored sparkling water beverages
  • Light yogurt and other dairy products
  • Low-sugar ice cream
  • Low-sugar gelatin desserts
  • Certain medications

What Are Aspartame Side Effects?

While aspartame is widely used as a sugar substitute, it's important to be aware of the potential side effects that could be associated with it. Know that the only condition where any amount of aspartame is directly related to adverse effects is phenylketonuria (PKU).2 This is a rare genetic condition where the body is unable to break down phenylalanine. Here are some of the key potential risks of consuming large amounts of aspartame that have been researched:

Increased Cravings

Aspartame and other low-calorie sweeteners make it taste like you’re eating sugar, but your body is rewarded with almost no calories (energy). This may trick your body in the short term, but the idea that you’ll make up for the lost energy by craving additional calories later on is something that researchers have been looking into for over a decade. A 2022 review of clinical studies found that replacing sugar with non-nutritive sweeteners does not result in an increase in calories in the short or long term, making this potential risk for weight gain appear a little less risky.3

Skin Problems

A dose-dependent side effect of aspartame is contact dermatitis, caused by a build-up of formaldehyde, an aspartame metabolite that leads to systemic skin inflammation. Generalized skin swelling and eyelid dermatitis in adults and children consuming large amounts of aspartame have been reported and quickly resolved by the discontinuation of aspartame-containing medications and sweeteners.3

Early Menstruation

A 10-year study of 2,379 girls initially aged 9 to 10 found that girls who drank one or more artificially sweetened soft drinks per day had a 43% higher risk of getting their first menstrual period before age 11.4 Aspartame was the most frequently used artificial sweetener in the drinks reported. The reason for this is unclear, and scientists hypothesize that it may be related to alterations in the gut microbiota or glucose regulation, which may impact menstruation but could also be impacted by previous dieting behaviors, weight, and other variables. 

Damage to Kidney and Liver

High doses of aspartame could increase free radical production in kidney tissue and an increase in liver enzymes, leading to significant damage over time.5, 6 These results have been found in animal studies where large amounts of aspartame are used, implying potential toxic effects at high amounts. 

Mood Swings

One small study with 28 participants found that eating a high-aspartame diet of 25mg/kg body weight/day reported more irritable moods, exhibited more depression, and performed worse on spatial orientation tests, suggesting that aspartame may have cognitive and mood effects.7 As studies that compare results from participants consuming amounts of aspartame typically found in diet drinks did not find that it had any impact or effect on mood or cognition, more research on this topic is needed.

<p class="pro-tip"><strong>Also Read: </strong><a href=depression-and-blood-sugar>How Depression and Anxiety Relate To Your Blood Sugar</a>.</p>

Does Aspartame Cause Cancer?

Artificial sweeteners on a table

One of the most controversial and researched aspects of Aspartame is its potential link to cancer risk. The connection between aspartame and cancer comes down to the metabolites that are produced and released in the body as aspartame is broken down. 

When you eat aspartame, it’s broken down into several components, including methanol, which is then converted into formaldehyde, a known carcinogen.2 The amount of formaldehyde produced from the breakdown of aspartame is generally considered low and safe by regulating bodies like the FDA, but some studies have suggested otherwise. 

Due to these concerns, the International Agency for Research on Cancer (IARC) has classified Aspartame as “possibly carcinogenic to humans.” This means that while some evidence suggests a potential risk, it is not conclusive. In 2023, the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) Joint Expert Committee on Food Additives (JECFA) released a statement that the acceptable daily intake (ADI) of aspartame remains at 0-40mg/kg body weight.

This means that someone who is 70kg (or 154 pounds) would need to drink 9 to 14 cans of aspartame-containing diet drinks to exceed the safe limit and risk negative outcomes. More research is needed to fully understand the long-term effects and safety of aspartame consumption and its potential role in cancer development.

What Are Aspartame Alternatives?

If you're looking to cut back on Aspartame or avoid it altogether, there are plenty of other sugar substitutes available that can help you satisfy your sweet tooth without the potential risks. Here are some natural and artificial sweeteners that you can use as alternatives to aspartame:

Monk Fruit Extract

Monk fruit is a natural sweetener that is about 250 times sweeter than sugar. It has no calories and does not affect blood sugar levels, making it a great option for those managing diabetes or looking to reduce calorie intake.9


Allulose is a low-calorie sugar found naturally in small quantities in foods like molasses, figs, and maple syrup.  It has about 70% of the sweetness of sugar and can be used similarly to sugar in baked goods and recipes, making it a popular choice. Best of all, recent research has found that allulose may play a role in improving insulin resistance and glucose metabolism.10


You’ll most commonly see sucralose by the brand name Splenda. This artificial sweetener is about 600 times sweeter than sugar and is often used for baking and sweetening beverages. However, research has found that sucralose, like aspartame, may have adverse effects on your health as well.11


Stevia is a natural sweetener from the leaves of the Stevia plant. It’s around 250-300 times sweeter than sugar and has zero calories. The stevia plant has properties that are protective against diabetes, cancer, inflammation, and tumors, and the stevia sweetener has no effect on blood sugar, making it a good option for people with diabetes.12

Sugar Alcohols

Sugar alcohols include ingredients like erythritol, xylitol, mannitol, and sorbitol. They’re naturally extracted from fruits and vegetables and are less sweet than sucrose, but they contribute almost no calories and have no effect on blood sugar.13 These sweeteners are often used in sugar-free candies, gums, and baked goods.

Learn More About How to Improve Blood Sugar Health With Signos’ Expert Advice

Aspartame is an ingredient you’ll come across often when choosing foods and drinks that are lower in calories and sugar. Choosing the right sugar substitute for you and your health journey is all part of improving your blood sugar and reaching your goals. Signos’ expert advice can help make your health and wellness journey more effective. Learn how Signos can improve your health and improve your glucose levels. To see if Signos is the right fit for you, take our quick quiz and get started!

<p class="pro-tip"><strong>Learn More: </strong><a href=what-is-xylitol>What Is Xylitol: Benefits, Side Effects, and Uses Explained</a>.</p>

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Topics discussed in this article:


  1. U.S. Food and Drug Administration. (2023). Aspartame and other sweeteners in food.
  2. Czarnecka, K., Pilarz, A., Rogut, A., Maj, P., Szymańska, J., Olejnik, Ł., & Szymański, P. (2021). Aspartame-True or False? Narrative Review of Safety Analysis of General Use in Products. Nutrients, 13(6), 1957. 
  3. Wilk, K., Korytek, W., Pelczyńska, M., Moszak, M., & Bogdański, P. (2022). The Effect of Artificial Sweeteners Use on Sweet Taste Perception and Weight Loss Efficacy: A Review. Nutrients, 14(6), 1261. 
  4. Mueller, N. T., Jacobs, D. R., Jr, MacLehose, R. F., Demerath, E. W., Kelly, S. P., Dreyfus, J. G., & Pereira, M. A. (2015). Consumption of caffeinated and artificially sweetened soft drinks is associated with risk of early menarche. The American journal of clinical nutrition, 102(3), 648–654. 
  5. Ardalan, M. R., Tabibi, H., Ebrahimzadeh Attari, V., & Malek Mahdavi, A. (2017). Nephrotoxic Effect of Aspartame as an Artificial Sweetener: a Brief Review. Iranian journal of kidney diseases, 11(5), 339–343. 
  6. Finamor, I., Pérez, S., Bressan, C. A., Brenner, C. E., Rius-Pérez, S., Brittes, P. C., Cheiran, G., Rocha, M. I., da Veiga, M., Sastre, J., & Pavanato, M. A. (2017). Chronic aspartame intake causes changes in the trans-sulphuration pathway, glutathione depletion and liver damage in mice. Redox biology, 11, 701–707. 
  7. Lindseth, G. N., Coolahan, S. E., Petros, T. V., & Lindseth, P. D. (2014). Neurobehavioral effects of aspartame consumption. Research in nursing & health, 37(3), 185–193. 
  8. World Health Organization. (2023). Aspartame hazard and risk assessment results released. 
  9. Wang, S., Su, S., Li, J., Lai, W., & Zhang, Z. (2020). Monk fruit (Siraitia grosvenorii): Health aspects and food applications. ResearchGate. 
  10. Xia, Y., Cheng, Q., Mu, W., Hu, X., Sun, Z., Qiu, Y., Liu, X., & Wang, Z. (2021). Research Advances of d-allulose: An Overview of Physiological Functions, Enzymatic Biotransformation Technologies, and Production Processes. Foods (Basel, Switzerland), 10(9), 2186. 
  11. Schiffman, S. S., & Rother, K. I. (2013). Sucralose, a synthetic organochlorine sweetener: overview of biological issues. Journal of toxicology and environmental health. Part B, Critical reviews, 16(7), 399–451. 
  12. Peteliuk, V., Rybchuk, L., Bayliak, M., Storey, K. B., & Lushchak, O. (2021). Natural sweetener Stevia rebaudiana: Functionalities, health benefits and potential risks. EXCLI journal, 20, 1412–1430.
  13. Mazi, T. A., & Stanhope, K. L. (2023). Erythritol: An In-Depth Discussion of Its Potential to Be a Beneficial Dietary Component. Nutrients, 15(1), 204.

About the author

Kelsey Kunik is a registered dietitian, health and wellness writer, and nutrition consultant

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Please note: The Signos team is committed to sharing insightful and actionable health articles that are backed by scientific research, supported by expert reviews, and vetted by experienced health editors. The Signos blog is not intended to diagnose, treat, cure or prevent any disease. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider. Read more about our editorial process and content philosophy here.

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