E955 — Sucralose
Also labelled: Splenda · Sucralose
Sucralose is around 600 times sweeter than sugar and passes through the body largely unchanged, which is the basis for its safety case. The open questions concern what happens when it is heated in baking, and what it does to the gut microbiome.
At a glance
- E number
- E955
- Class
- Sweetener
- Origin
- Synthetic, made by selectively chlorinating sucrose
- EU status
- Authorised, with maximum levels by food category
- Acceptable daily intake
- 15 mg per kg of body weight per day (EFSA)
- Typically found in
- Diet drinks, sugar-free desserts, protein powders, baked goods, tabletop sweeteners
What it actually is
Sucralose is made from sucrose by replacing three hydroxyl groups with chlorine atoms. That modification makes it intensely sweet and, importantly, largely indigestible: the majority passes through unabsorbed and is excreted unchanged.
That non-metabolism is the core of the safety argument — a substance that is not broken down and not retained has limited opportunity to do systemic harm.
The heating question
Unlike aspartame, sucralose is stable enough to survive cooking, which is why it appears in baked goods and is sold for home baking. But at high temperatures — generally cited above roughly 120 °C, and more so above 180 °C — it can begin to break down, and studies have reported the formation of chlorinated compounds including chloropropanols under some conditions.
This has been flagged as needing further evaluation rather than resolved as a hazard. It is the main reason sucralose sits above the sweeteners with no open questions rather than alongside them.
Microbiome and glucose response
A body of research has looked at whether non-nutritive sweeteners alter gut bacteria or glucose handling. Results are mixed and often come from animal studies or small human trials with high doses, and the field has not converged.
In 2023 the WHO issued a guideline advising against using non-sugar sweeteners for weight control, on the grounds that long-term benefit is not demonstrated. That guidance is about effectiveness rather than toxicity, and it applies to the category as a whole rather than to sucralose specifically.
How Frela scores it
Frela rates E955 moderate risk — above sweeteners with clean evaluations, below aspartame's precautionary high.
As with other sweeteners, expect the overall score of a diet product to be pulled in two directions: the nutrition component responds well to the absence of sugar, while the additive and processing components respond to how the product is built. Frela shows both rather than netting them into a verdict.
Common questions
Is it safe to bake with sucralose?
Regulators authorise it for use in baked goods. The open question about high-temperature breakdown products has been raised for further evaluation rather than settled, which is reflected in the moderate rating.
Does sucralose spike blood sugar?
It contributes essentially no digestible carbohydrate. Whether it has indirect effects on glucose handling through the microbiome is actively researched and unresolved.
Is it better than aspartame?
Neither has an established harm at normal intake. Aspartame carries an IARC 2B classification; sucralose carries open questions about heating and microbiome effects. Frela rates aspartame higher risk on the strength of the classification.
Sources
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