Sucralose and aspartame are two artificial sweeteners. Both have been well-studied and are safe to consume.

Consuming excessive amounts of sugary foods and beverages has been linked to many adverse health effects, including diabetes, depression, and heart disease (1, 2, 3, 4).

Cutting down on added sugars may reduce your risk of these negative effects, as well as obesity, a condition that can put you at risk of certain cancers (5, 6, 7).

Sugar substitutes may be an appealing option if you’re trying to reduce your sugar intake. Yet, you may wonder how popular artificial sweeteners like sucralose and aspartame differ — and whether they’re safe to use.

This article explores the differences between sucralose and aspartame.

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Sucralose vs. aspartame

Sucralose and aspartame are sugar replacements that are used to sweeten foods or beverages without adding a significant number of calories or carbs.

Sucralose is widely sold under the brand name Splenda, while aspartame is typically found as NutraSweet or Equal.

While they’re both high-intensity sweeteners, they differ in terms of their production methods and sweetness.

One packet of either sweetener is meant to mimic the sweetness of 2 teaspoons (8.4 grams) of granulated sugar, which has 32 calories (8).

Sucralose

Interestingly, though it’s calorie-free, sucralose is made from common table sugar. It debuted on the market in 1998 (9, 10, 11).

To make sucralose, sugar undergoes a multistep chemical process in which three pairs of hydrogen-oxygen atoms are replaced with chlorine atoms. The resulting compound is not metabolized by the body (11).

Because sucralose is incredibly sweet — about 600 times sweeter than sugar — it’s often mixed with bulking agents like maltodextrin or dextrose (9, 11).

However, these fillers typically add a few, yet insignificant, number of calories.

So while sucralose itself is calorie-free, the fillers found in most sucralose-based sweeteners like Splenda provide about 3 calories and 1 gram of carbs for every 1-gram serving (12).

Maltodextrin and dextrose are typically made from corn or other starch-rich crops. Combined with sucralose, they contain 3.36 calories per gram (12, 13).

That means one packet of Splenda contains 11% of the calories in 2 teaspoons of granulated sugar. Thus, it’s considered a low calorie sweetener (8, 12).

The acceptable daily intake (ADI) of sucralose is 2.2 mg per pound (5 mg per kg) of body weight. For a 132-pound (60-kg) person, this equals about 23 single-serve (1-gram) packets (9).

Given that 1 gram of Splenda contains mostly filler and only 1.1% sucralose, it’s unlikely that many people will regularly consume amounts beyond these safety recommendations (14).

Aspartame

Aspartame comprises two amino acids — aspartic acid and phenylalanine. While these are both naturally occurring substances, aspartame is not (15).

Although aspartame has been around since 1965, the Food and Drug Administration (FDA) did not approve it for use until 1981.

It’s considered a nutritive sweetener because it contains calories — though only 4 calories per gram (9).

Being 200 times sweeter than sugar, only a small amount of aspartame is used in commercial sweeteners. Like sucralose, aspartame-based sweeteners usually contain fillers that mellow the intense sweetness (9).

Products like Equal therefore contain some calories from fillers like maltodextrin and dextrose, though it’s an insignificant amount. For example, one single-serve (1-gram) packet of Equal has only 3.65 calories (16).

The ADI for aspartame, which was set by the FDA, is 22.7 mg per pound (50 mg per kg) of body weight per day. For a 132-pound (60-kg) person, that equals the amount found in 75 single-serve (1-gram) packets of NutraSweet (9).

For further context, one 12-ounce (355-ml) can of diet soda contains about 180 mg of aspartame. This means that a 165-pound (75-kg) person would have to drink 21 cans of diet soda to surpass the ADI (17).

Does Splenda contain aspartame?

Almost 99% of the contents of a Splenda packet comprises fillers in the form of dextrose, maltodextrin, and moisture. Only a tiny amount is the intensely sweet sucralose (14).

Similarly, aspartame-based sweeteners contain some of the same fillers.

Thus, while aspartame- and sucralose-based sweeteners share some of the same fillers, Splenda does not contain aspartame.

Sucralose and aspartame are artificial sweeteners. Fillers help mellow their intense sweetness and add a few calories. Splenda does not contain aspartame, though it has fillers that are also found in aspartame-based sweeteners.

Health effects

A lot of controversy surrounds the safety and long-term health effects of artificial sweeteners like sucralose and aspartame.

The European Food Safety Authority (EFSA) reviewed over 600 studies on aspartame in 2013 and found no reason to believe it isn’t safe for consumption (10, 18).

Sucralose has also been thoroughly researched, with over 100 studies pointing to its safety (19).

Specifically, there have been concerns about aspartame and brain cancer — yet extensive studies have found no link between brain cancer and consuming artificial sweeteners within safe limits (17, 19, 20, 21).

Other side effects associated with the use of these sweeteners include headaches and diarrhea. If you experience these symptoms consistently after consuming foods or beverages containing these sweeteners, they may not be a good choice for you.

Furthermore, recent concerns have been raised regarding the negative effects of the long-term use of artificial sweeteners on healthy gut bacteria, which are needed for optimal health. However, the current research was conducted in rats, so human studies are needed before conclusions can be made (14, 22, 23, 24).

Effects on blood sugar and metabolism

Several human studies have linked aspartame to glucose intolerance. However, a lot of this research has focused on adults with obesity (25, 26, 27).

Glucose intolerance means that your body can’t metabolize sugar properly, causing elevated blood sugar levels. More research is needed to understand the long-term effects of sugar substitutes on sugar metabolism — both in adults with and without obesity (25, 26, 27, 28).

Additionally, some research has found that the long-term use of aspartame may increase systemic inflammation, which is linked to many chronic illnesses like cancer, diabetes, and heart disease (17, 29).

Lastly, recent research suggests that sucralose may have unwanted effects on your metabolism. Yet, other evidence associates consuming artificial sweeteners in place of sugar with modest weight loss of 1.7 pounds (0.8 kg) (27, 30, 31, 32).

Therefore, more research is needed on the long-term health effects of artificial sweeteners.

May be harmful at high temperatures

The European Union banned the use of all artificial sweeteners in commercially prepared baked goods on February 13, 2018 (10).

This is because some sweeteners like sucralose and aspartame — or Splenda and NutraSweet — may be chemically unstable at higher temperatures, and their safety at these temperatures is less researched (30).

Therefore, you should avoid using aspartame and sucralose for baking or high-temperature cooking.

Some studies link the use of aspartame, sucralose, and other artificial sweeteners to adverse health effects. These may include an altered gut microbiome and metabolism. You should avoid baking or cooking with artificial sweeteners at high temperatures.

Which is better for you?

Both aspartame and sucralose were developed to provide the sweetness of sugar without the calories. They are both considered generally safe for use within their stated safe limits.

Sucralose is a better choice if you have phenylketonuria (PKU), a rare genetic condition, as aspartame contains the amino acid phenylalanine.

Additionally, if you have kidney issues, you should keep your aspartame intake to a minimum, as this sweetener has been linked to added kidney strain (33).

Moreover, those taking medications for schizophrenia should avoid aspartame altogether, as the phenylalanine found in the sweetener could lead to uncontrolled muscle movements, or tardive dyskinesia (34, 35).

Both sweeteners are considered generally safe. That said, their long-term effects are not yet well understood.

Sucralose may be a better option for those with kidney issues, those who have the genetic condition phenylketonuria, and those taking certain medications for schizophrenia.

The bottom line

Sucralose and aspartame are two popular artificial sweeteners.

Both contain fillers like maltodextrin and dextrose that mellow their intense sweetness.

There’s some controversy regarding their safety, but both sweeteners are well-studied food additives.

They may be appealing to those looking to decrease their sugar intake — thus potentially decreasing their risk of certain chronic conditions like diabetes and heart disease.

However you go about it, reducing your added sugar intake may be a good path to better health.

If you choose to avoid sucralose and aspartame, there are many great alternatives on the market.