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 (Splenda).

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 multi-step chemical process in which 3 hydrogen-oxygen groups are replaced with chlorine atoms.

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

Splenda products were then jointly developed by the companies Tate & Lyle and Johnson & Johnson. It was introduced in the US 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 carbs 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 does not have a bitter aftertaste like many other popular sweeteners (2, 3).

Summary Sucralose is an artificial sweetener. The most popular product made from it is called Splenda. 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 severely obese people who did not regularly consume artificial sweeteners reported that sucralose elevated blood sugar levels by 14%, and insulin levels by 20% (4).

Several other studies in healthy, normal-weight people have found no effects on blood sugar and insulin levels. However, these studies included people who regularly consumed 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 consuming sucralose, it probably won't have any effect.

Summary Sucralose may raise blood sugar and insulin levels in people who do not 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. Yet, recent studies have challenged this.

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

One study found that heating sucralose with glycerol, the backbone of 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 or 120°C in the meantime (10, 11).

Summary At high temperatures, sucralose may break down and generate harmful substances.

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 12 weeks after the experiment was finished (14).

Nevertheless, as this was a study in rats, more research is needed to explore whether sucralose really affects gut bacteria in humans.

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 find no connection between artificial sweetener consumption and body weight or fat mass, but some of them report a small increase in body mass index (15).

A review of randomized controlled trials — the gold standard of 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 do not seem to have any major effects on body weight.

Like other artificial sweeteners, sucralose is highly controversial. Some claim that it is 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, and health authorities like the 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, then it's probably fine to use in moderation. There is certainly no clear-cut evidence that it’s harmful to humans.

However, it may be a bad choice for high-heat cooking and baking.

Additionally, if you notice persistent problems related to your gut health, it may be worth exploring whether sucralose could be the reason.

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