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Is Sucralose (Splenda) Bad for You? Evidence-Based Answers

October 13, 2020

  • Sucralose is an artificial sweetener with zero calories.
  • Sucralose can be found at most restaurants and grocery stores as a sugar substitute.
  • People consume sucralose to indulge their sugar cravings without the dangers of regular sugar (sucrose).
  • Many experts say that sucralose is safe to consume. However, decades of research are conflicting and sucralose may not be as safe as the FDA would have you believe.

What is sucralose?

Sucralose is an artificial sweetener and sugar substitute found in many products such as diet sodas and chewing gums. It is not a natural sweetener, like honey or allulose.

It contains no calories and is a 0 on the glycemic index (which means it does not affect blood glucose levels). Sucralose is about 600 times sweeter than sugar, so a little bit goes a long way.

Sucralose is created by a process called “bleaching” sugar. Manufacturers take sucrose (regular sugar) and replace certain hydrogen-oxygen groups with chlorine atoms. This isn’t like chlorine in bleach — chlorine atoms in sucralose are not toxic or dangerous.

How was sucralose discovered? Allegedly, sucralose was discovered in 1976 when a scientist at Tate & Lyle misheard instructions and “tasted” sucralose, instead of “testing” it. Fortunately, this scientist did not die as a result, but found sucralose to be extremely sweet.

Brand names for sucralose:

  • Splenda
  • Canderel Yellow
  • SucraPlus
  • CandyS
  • Various store-brand bulk sucralose

What is Splenda? Splenda the most popular brand name of sucralose, available at virtually every restaurant to artificially sweeten your tea or coffee. However, Splenda is only 5% sucralose by volume.

Splenda is 95% dextrose and maltodextrin, both of which have nearly the same number of calories as sugar and are around 100 on the glycemic index. In other words, they spike your blood sugar just like table sugar does.

Unfortunately, Splenda has become synonymous with sucralose over the past few decades. Since they aren’t the same, we differentiate between the two.

Calories, Glycemic Index, Sweetness, & Acceptable Daily Intake

For reference, one packet (serving) of Splenda is 1 gram, but contains only 12 milligrams of sucralose.

*In the chart below, you will find that Splenda has a glycemic index (GI) of 100. This is actually difficult to determine, as this information is not readily available. However, the bulking agents used in Splenda are dextrose and maltodextrin. These bulking agents account for 95% of the volume of Splenda. They come in upwards of 100 on the glycemic index.

**One Splenda packet contains 12 milligrams, which is as sweet as 7-8 grams of sugar. Since a sugar packet serving contains about 3.5-4 grams of sugar, one packet of Splenda is about 2 times as sweet as a sugar packet.

Calories per gramGlycemic indexSweetnessAcceptable daily intake (ADI)
Sugar3.7565 out of 1001x41 g/day
Sucralose00 out of 100600x340 mg/day (for a 150-lb person)
Splenda3.36100* out of 1002x**28 packets (for a 150-lb person)

Is sucralose safe?

According to many worldwide experts and organizations, sucralose is safe. However, some research implies it is not safe and may interfere with insulin levels, cause weight gain, and increase heart disease and cancer risk.

Splenda, on the other hand, is almost certainly not a safe sugar substitute — especially for those with blood sugar issues.

However, many disagree. Sucralose has been a controversial topic for more than 20 years. Study after study reveals more negative effects that sucralose has on human health. But the sucralose industry puts out a study that refutes the negative study. And on and on it goes.

The U.S. Food and Drug Administration (FDA) has approved sucralose as safe for human consumption in all foods and beverages, including while pregnant.

There are no human studies to determine the safety of sucralose. Most of the research into the food safety of sucralose was performed in mice.

There’s also no conclusive evidence that sucralose does cause cancer in humans. We don’t know for sure if sucralose is safe. Yet government agencies and the mainstream scientific community assures the public that sucralose is obviously safe.

Is sucralose worse than sugar? Sucralose is better than sugar in a couple ways. Sucralose is a no-calorie sweetener. Whenever you consume excess calories, they can turn into body fat. Sucralose has no aftertaste, but it does not taste exactly like sugar. Even though sucralose may cause negative health effects, sugar is also to blame for a lot of health woes.

Is sucralose as bad for you as aspartame? Sucralose is safer than aspartame. Even though there are many studies implying that sucralose may affect our insulin levels, and gut health, heart health, aspartame is implicated in weight gain, birth defects, multiple sclerosis, migraines, lupus, Alzheimer’s disease, and cancer.

Diabetes, Blood Sugar, and Insulin

According to several scientific studies, sucralose clearly has an effect on human insulin levels and blood sugar levels. All of this contributes to the development of diabetes.

A 2018 study confirms that sucralose has the ability to decrease insulin sensitivity. “Insulin sensitivity” ensures insulin is able to effectively transport blood sugar to your cells for energy. Low insulin sensitivity is a sign of poor health and a predictor for type 2 diabetes.

Although researchers are careful to point out the difference between causality and correlation, an important study published in Diabetes Care showed that individuals who consumed diet sodas every day had a significantly greater risk of developing type 2 diabetes.

Recent research shows that consuming artificial sweeteners, such as sucralose, increases insulin resistance. “Insulin resistance” happens when your cells resist responding to insulin, which can lead to type 2 diabetes.

Sucralose was found to trigger an increase in insulin and blood glucose levels and decrease insulin sensitivity in a study of obese subjects. Therefore, sucralose may contribute to the development of type 2 diabetes and might be counterproductive to personal health goals.

Gut Health & The Microbiome

Sucralose may have a negative effect on gut health, including your gut microbiome.

Although sucralose may work against harmful bacteria present in your oral microbiome, it seems to alter your gut microbiome for the worse.

Sucralose does not alter your gut microbiome as much as another artificial sweetener, saccharin. Nevertheless, sucralose has been observed to negatively affect gut bacteria and even cause weight gain in animal studies.

Consuming the acceptable daily limit of sucralose for 6 months can lead to negatively altering your gut microbiome and liver inflammation.

This 2018 scientific article shows that Splenda may promote gut dysbiosis, which is when you have more harmful bacteria in your gut than beneficial bacteria. Splenda may double your risk of developing Crohn’s disease, an inflammatory bowel disease (IBD).

One researcher posited that sucralose may be responsible for the 600% increase in IBD patients in Canada over a short 20-year period.

Weight Management

Sucralose is said to help you with your weight loss goals, but it may actually contribute to weight gain.

According to two randomized trials, children consuming sucralose gained as much weight as children consuming regular sugar.

However, there are other studies showing the opposite.

Sucralose not only has some effect on weight, but also satiety. Satiety is how satisfied you are after eating. The less satisfied, the sooner you are going to want to eat again.

Sucralose and other artificial sweeteners do not satisfy many individuals the same way sugar does. This lack of satisfaction leads to more food consumed to reach that satisfaction, which may lead to weight gain.

Low-calorie sweeteners like sucralose promote “sugar cravings and sugar dependence” because they are so sweet.

Research shows that tricking your brain with non-sugar sweet tastes weakens the validity of sweetness as a physiological signal to expect energy gain.

Essentially, artificial sweeteners like sucralose harm your body’s ability to predict energy gain, which may result in “negative health outcomes such as type 2 diabetes, metabolic syndrome, and cardiovascular events.”

Heart Disease

Heart disease is the leading cause of death in the United States. Sucralose has been linked with an increased risk of heart disease.

Cohort studies suggest that artificial sweeteners, like acesulfame K or sucralose, may lead to:

  • Obesity
  • High blood pressure
  • Metabolic syndrome
  • Stroke
  • Heart disease

However, high sugar consumption is much more scientifically linked to heart disease than sucralose is. The American Heart Association recommends limiting added sugar.


According to early research, sucralose may contribute to the development of cancer. But the science here is scant.

A 2016 animal study demonstrated that feeding male mice high doses of sucralose significantly increased their malignant tumor count. The FDA has determined this study has too many issues to reconsider sucralose’s safety.

As discussed above, sucralose may reduce beneficial bacteria in your gut microbiome. Reductions and imbalances in your gut microbiome have been known to trigger inflammatory bowel disease, allergies, and gastric cancer.

A study published in Food Chemistry revealed that heating sucralose in the presence of glycerol released carcinogens called chloropropanols.

Dangers When Baking

Sucralose is thought to be heat stable up to 450 degrees Fahrenheit (232 degrees C). This means that sucralose does not melt until your oven is set to 450 degrees Fahrenheit or above.

But some experts are finding that baking with sucralose at high temperatures can release cancer-causing compounds.

A 2009 study observed sucralose to degrade at 246 degrees Fahrenheit (119 degrees Celsius), which is much lower than most baking recipes call for. Researchers found that sucralose liberated hydrogen chloride and water when heated to this temperature.

Hydrogen chloride is a highly toxic acid that can cause irritation of the lungs. Upon contact with water or water vapor, hydrogen chloride converts into hydrochloric acid, which can cause tissue corrosion and nausea.

According to one study published in Food Chemistry, “caution should be exercised in the use of sucralose as a sweetening agent during baking of food products containing glycerol or lipids.” This is because sucralose may release carcinogenic compounds when heated.

This study found that when sucralose is heated in the presence of glycerol, carcinogens were generated.

Pregnancy & Breastfeeding

While you are pregnant or breastfeeding, avoid sucralose.

Until more human clinical trials are performed, it is unsafe to consume sucralose, particularly if you are pregnant or breastfeeding.

Ask your doctor or dietitian before changing your diet while pregnant.

For Children

Avoid giving children sucralose. There is very little known about the long-term impact it may have on their development, and its impact on the gut is of particular concern.

A 2012 study observed over 600 children, split into two groups — one who drank calorie-free beverages, sweetened with sucralose and Ace-K, and another group drinking sugar-sweetened beverages containing 104 calories.

After a year and a half, the average weight difference between groups was only 2 pounds higher for children who had 46,000 additional calories from sugar. This inexplicable result suggests that sucralose may not protect from obesity and could act similarly to sugar.

The Best Alternative Sweeteners

Sucralose is a controversial sugar substitute. With the potential dangers of sucralose in mind, we would not suggest sucralose as the best alternative sweetener.

But each individual has their own nutrition journey. If you aren’t worried about the GI of Splenda or the potential toxicity of sucralose in humans, sucralose may be the sweetener for you.

What is the safest artificial sweetener to use? Stevia is probably the safest sugar substitute to use. Stevia has zero calories, 0 on the glycemic index, and comes with no side effects. Monk fruit extract is a close second best sugar substitute for the same reasons.

If you’re looking to replace table sugar with a sugar alcohol, xylitol and erythritol are the two best sugar alcohols. Sugar alcohols taste more like sugar than stevia or monk fruit, but consuming high amounts of sugar alcohols may cause some gastrointestinal distress.


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