Excessive amounts of added sugar can have harmful effects on your metabolism and overall health.

For this reason, many people turn to artificial sweeteners like sucralose.

However, while authorities claim that sucralose is safe to eat, some studies have linked it to health problems.

This article takes an objective look at sucralose and its health effects — both good and bad.

Sucralose is a zero calorie artificial sweetener, and Splenda is the most common sucralose-based product.

Sucralose is made from sugar in a multistep chemical process in which three hydrogen-oxygen groups are replaced with chlorine atoms.

It was discovered in 1976 when a scientist at a British college allegedly misheard instructions about testing a substance. Instead, he tasted it, realizing that it was highly sweet.

The companies Tate & Lyle and Johnson & Johnson then jointly developed Splenda products. It was introduced in the United States in 1999 and is one of the most popular sweeteners in the country.

Splenda is commonly used as a sugar substitute in both cooking and baking. It's also added to thousands of food products worldwide.

Sucralose is calorie-free, but Splenda also contains the carbohydrates dextrose (glucose) and maltodextrin, which brings the calorie content up to 3.36 calories per gram (1).

However, the total calories and carbs Splenda contributes to your diet are negligible, as you only need tiny amounts each time.

Sucralose is 400–700 times sweeter than sugar and doesn’t have a bitter aftertaste like many other popular sweeteners (2, 3).

Summary Sucralose is an artificial sweetener. Splenda is the most popular product made from it. Sucralose is made from sugar but contains no calories and is much sweeter.

Sucralose is said to have little or no effects on blood sugar and insulin levels.

However, this may depend on you as an individual and whether you're used to consuming artificial sweeteners.

One small study in 17 people with severe obesity who didn’t regularly consume these sweeteners reported that sucralose elevated blood sugar levels by 14% and insulin levels by 20% (4).

Several other studies in people with average weight who didn’t have any significant medical conditions have found no effects on blood sugar and insulin levels. However, these studies included people who regularly used sucralose (5, 6, 7).

If you don't consume sucralose on a regular basis, it's possible that you may experience some changes to your blood sugar and insulin levels.

Yet, if you're used to eating it, it probably won't have any effect.

Summary Sucralose may raise blood sugar and insulin levels in people who don’t consume artificial sweeteners regularly. However, it probably has no effect on people who regularly use artificial sweeteners.

Splenda is considered to be heat resistant and good for cooking and baking. However, recent studies have challenged this.

It seems that at high temperatures, Splenda starts to break down and interact with other ingredients (8).

One study found that heating sucralose with glycerol, a compound found in fat molecules, produced harmful substances called chloropropanols. These substances may raise cancer risk (9).

More research is needed, but it may be best to use other sweeteners instead when baking at temperatures above 350°F (175°C) in the meantime (10, 11).

Summary At high temperatures, sucralose may break down and generate harmful substances that could increase your risk of cancer.

The friendly bacteria in your gut are extremely important for your overall health.

They may improve digestion, benefit immune function and reduce your risk of many diseases (12, 13).

Interestingly, one rat study found that sucralose may have negative effects on these bacteria. After 12 weeks, rats that consumed the sweetener had 47–80% fewer anaerobes (bacteria that don't require oxygen) in their guts (14).

Beneficial bacteria like bifidobacteria and lactic acid bacteria were significantly reduced, while more harmful bacteria seemed to be less affected. What's more, the gut bacteria had still not returned to normal levels after the experiment was completed (14).

Yet, human research is necessary.

Summary Animal studies link sucralose to negative effects on the bacterial environment in the gut. However, human studies are needed.

Products that contain zero-calorie sweeteners are often marketed as being good for weight loss.

However, sucralose and artificial sweeteners don't seem to have any major effects on your weight.

Observational studies have found no connection between artificial sweetener consumption and body weight or fat mass, but some of them report a small increase in Body Mass Index (BMI) (15).

A review of randomized controlled trials, the gold standard in scientific research, reports that artificial sweeteners reduce body weight by around 1.7 pounds (0.8 kg) on average (15).

Summary Sucralose and other artificial sweeteners don’t seem to have any major effects on body weight.

Like other artificial sweeteners, sucralose is highly controversial. Some claim that it’s entirely harmless, but new studies suggest that it may have some effects on your metabolism.

For some people, it may raise blood sugar and insulin levels. It may also damage the bacterial environment in your gut, but this needs to be studied in humans.

The safety of sucralose at high temperatures has also been questioned. You may want to avoid cooking or baking with it, as it may release harmful compounds.

That being said, the long-term health effects are still unclear, but health authorities like the Food and Drug Administration (FDA) do consider it to be safe.

Summary Health authorities consider sucralose to be safe, but studies have raised questions about its health effects. The long-term health effects of consuming it are unclear.

If you like the taste of sucralose and your body handles it well, it's probably fine to use in moderation. There’s certainly no clear cut evidence that it’s harmful to humans.

However, it may not be a good choice for high heat cooking and baking.

Additionally, if you notice persistent problems related to your gut health, talk to your healthcare provider about exploring whether sucralose could be the reason.

If you choose to avoid sucralose or artificial sweeteners in general, there are plenty of great alternatives.