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Sucralose vs. Aspartame: Comparing Artificial Sweeteners

Monica McCafferty, MS, CNS

Published in Nutrition

9 min read

October 25, 2022
Person holding sugar free alternative
Person holding sugar free alternative

If you chew sugar-free gum or drink diet or sugar-free beverages, it’s likely that you have encountered sweeteners like aspartame and sucralose. Similarly to stevia and Splenda, these sugar substitutes are both high-intensity sweeteners that are used in a wide variety of products. 

But is one better than the other? Read on to learn more about the similarities and differences between sucralose and aspartame.

Is Sucralose the Same as Aspartame?

Spoon of sugar

Sucralose and aspartame are both artificial, high-intensity sweeteners that are often used in place of table sugar. Aspartame is about 200 times sweeter than sugar, while sucralose is about 600 times sweeter than sugar. These sweeteners also contain different amounts of calories and carbs, which we’ll learn about later. 

While each of these sugar substitutes are used to sweeten foods and beverages without adding significant calories or carbohydrates, they are each produced differently and can have distinct effects on the body. 

What is Sucralose?

Sucralose is the only non-caloric sweetener made from sugar. It is made by replacing three hydroxyl groups in sugar with three chlorine atoms. This process creates a sweetener that is not able to be broken down by the body, meaning that it imparts zero calories when eaten. Sucralose was approved for use by the FDA in 1998. 

How Is Sucralose Used?

Sucralose is used as a sugar substitute in a number of commercial products, including baked goods, beverages, chewing gum, gelatin, and frozen dairy desserts. It is also available as a tabletop sweetener under the brand name Splenda.

Splenda, however, also contains maltodextrin and dextrose, which act as sweeteners and preservatives and will add some additional calories and carbohydrates compared to plain sucralose. Some studies have shown that sucralose can generate toxic compounds when heated, meaning that it may not be suitable for baking.

Benefits of Sucralose

The main benefit of sucralose is that it is calorie-free and not metabolized by the normal pathways of the body, which has led some people to conclude that it may not impact weight. However, this topic is still under investigation.

Sucralose is also non-cariogenic, meaning it doesn’t interact with bacteria in your mouth and is not likely to cause tooth decay.

What is Aspartame?

Spoon of aspartame

Aspartame is a low-calorie sweetener that was discovered in 1965 and approved by the FDA in the 1980s. Chemically, aspartame is a synthetic dipeptide formed by the reaction of two amino acids: L-aspartic acid and L-phenylalanine methyl ester. Unlike most other low-calorie sweeteners, it is completely broken down by the body.

Aspartame has about four calories per gram, just like sugar. However, because it is 200 times sweeter than sugar, much less of it is needed to reach the same sweet taste. This keeps the calories per serving of aspartame very low. 

How is Aspartame Used?

Aspartame is sold as a tabletop sweetener under the brand names NutraSweet and Equal, which also contain sweeteners like maltodextrin and acesulfame potassium. It is also used to sweeten many commercial products, including chewing gum, breakfast cereal, diet sodas, and carbonated beverage syrup bases. 

It’s used as a dry base for certain foods, like instant coffee and tea, gelatins, puddings, fillings, and dairy products and toppings. It is not generally found in baked goods because it loses its sweetness once heated. Aspartame is also found in about 600 pharmaceutical products. 

Benefits of Aspartame

Studies show that aspartame has little direct effect on blood glucose. It also has the ability to intensify and extend fruit flavors, like cherry and orange, in foods and drinks. This is why the flavor and sweetness of chewing gum sweetened with aspartame lasts longer than gum sweetened with real sugar. 

Sucralose vs Aspartame: How do They Compare? 

Spoons with sugar cubes and sugar free substitutes

So, what is the difference between aspartame and sucralose? Let’s have a better look at what sets these two sweeteners apart.

Nutritive vs. Non-Nutritive

Sucralose is a non-nutritive sweetener, while aspartame is a nutritive sweetener. To be considered non-nutritive, a sweetener has to contain less than two percent of the calories in an equivalent amount of sugar. Non-nutritive sweeteners such as sucralose and saccharin are very low in calories or have no calories at all. 

Aspartame does add caloric value to the foods that contain it, making it a nutritive sweetener. To be considered nutritive, a sweetener must contain more than two percent of the calories in an equivalent amount of sugar.  However, aspartame is usually added in such small amounts that any calories it may add are usually minimal. 


Aspartame and sucralose are both synthetic, meaning they are created chemically and are not found in nature. Aspartame is formed by the reaction of the amino acids L-aspartic acid and L-phenylalanine methyl ester. And as we mentioned earlier, sucralose is made by replacing three hydroxyl groups in sugar with three chlorine atoms. 


Sucralose is about 600 times as sweet as sucrose (or normal sugar), while aspartame is about 200 times as sweet. Because it’s the only sugar substitute made from sugar, sucralose has a very sugar-like taste without the bitter aftertaste sometimes present in sugar substitutes such as stevia.

Conversely, some people find that aspartame has a bitter and metallic aftertaste. For this reason, it is often blended with other sweeteners to minimize its aftertaste. 

How Sucralose and Aspartame Affect Your Health 

How do sucralose and aspartame compare when it comes to effects on your health? Do they have an effect on blood sugar? Let’s take a closer look at their potential side effects. 

Blood Sugar and Insulin Levels

Person pricking finger to check blood glucose

The purported benefits of sugar substitutes is that they are unlikely to affect your blood sugar. But is this really true? One 2003 study of 128 people with type 2 diabetes found that a daily dose of sucralose that was three times the recommended daily intake had no effect on the subjects’ blood glucose. 

However, a 2013 study found that sucralose affected glucose and insulin responses in people who do not normally consume non-nutritive sweeteners. Another randomized controlled trial in 2018 demonstrated that sucralose may in fact impair insulin sensitivity

This is a concern for diabetes risk, since reduced insulin sensitivity is a known risk factor for insulin resistance and diabetes. More research is needed to determine the connection between sucralose and blood sugar, however according to Dr. Danielle Kelvas of the HCG Institute, "Recent studies currently suggest that sucralose intake is safe for most people."

In the case of aspartame, a 2016 study of 2,856 adults with obesity found that aspartame was associated with glucose intolerance. However, other studies have stated that aspartame has no effect on glucose tolerance or insulin levels. 

A 2018 review of studies that link aspartame to effects on blood glucose found that aspartame could increase cortisol levels and may be associated with insulin deficiency or resistance. However, the researchers noted that they were not able to make a definitive link between aspartame and blood glucose or insulin production.

Metabolism and Body Weight

A 2014 review found that substituting low-calorie sweeteners like sucralose and aspartame for sugar could result in modest weight loss and reduction in fat mass and waist circumference. However, other studies have shown that artificial sweeteners may increase your appetite and cravings for sugary foods, which could lead people to gaining weight in the long run. 

Healthy Gut Bacteria

Animal studies have shown that sucralose may have a negative effect on your gut bacteria by decreasing the amount of healthy bacteria in the gut and may enhance pro-inflammatory gene expression, which can negatively impact other organs such as the liver. 

The research also states that, because aspartame is absorbed and broken down rapidly in the small intestine and never reaches the large intestine, it is unlikely to have an effect on the gut microbiome. However, one animal study observed changes in the microbial composition after consumption of aspartame. 

These mice also developed glucose intolerance, although researchers are still trying to understand the mechanisms involved. Long-term human studies are needed to establish how exactly artificial sweeteners may affect the gut microbiome. 

Are Sucralose or Aspartame Worse For You Than Sugar?

Cup of coffee with spoon on top that is holding a sugar cube

Artificial sweeteners are often the subject of controversy because of their potential negative health effects. Though many studies have confirmed the safety of artificial sweeteners, other research has found potentially negative health effects. More research is needed to determine exactly how these sweeteners can affect your health over time. 

It’s also important to note that most of these studies have had limitations, such as small sample sizes, using high doses that humans are unlikely to consume, or only testing their effects on animals. Currently, both sucralose and aspartame are approved for use by the U.S. Food and Drug Administration (FDA) and are considered safe.

Health Effects of Sugar 

On the other hand, the negative effects of too much sugar have been studied in depth. Research shows that a diet high in sugar can make you three times as likely to die from heart disease. Added sugar can increase your risk of high blood sugar, high blood pressure, insulin resistance, fatty liver disease, and obesity —  all of which are independent risk factors for cardiovascular disease.

Sugar has also been shown to cause chronic inflammation, and has been shown to be an individual risk factor in developing rheumatoid arthritis. Studies have also shown that sugar greatly increases your chances of developing type 2 diabetes, and even certain types of cancer

In the long run, aspartame and sucralose may help you reduce your added sugar intake, which could be beneficial to your overall well being. However, it may be a good idea to use them sparingly, as more research is needed to determine the long-term effects of sucralose and aspartame on the body.

So, Should You Use Aspartame or Sucralose?

Packets of sugar free alteratives

When it comes to choosing between aspartame or sucralose, it depends on your preference and what you plan to use it for. For example, you may want to avoid using either sweetener when baking, as aspartame loses its flavor after being heated and sucralose may generate toxic compounds when cooked at high temperatures.

Dr. Kelvas continues,

"In general, I encourage everyone to completely avoid artificial sweeteners whenever possible. Our body was not created or designed to process anything artificial, and just because the current study says it may be safe doesn't necessarily mean that it's optimal for your health."

Some studies have also suggested that aspartame has the potential to cause headaches. If you experience headaches or other negative side effects after consuming aspartame, it may be a good idea to avoid it and opt for sucralose or a natural sweetener such as stevia instead. 

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Heather Davis, MS, RDN, LDN

Reviewed by: Heather Davis, MS, RDN, LDN

Heather is a Registered and Licensed Dietitian Nutritionist (RDN, LDN), subject matter expert, and technical writer, with a master's degree in nutrition science from Bastyr University. She has a specialty in neuroendocrinology and has been working in the field of nutrition—including nutrition research, education, medical writing, and clinical integrative and functional nutrition—for over 15 years.

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