At a glance
How does Sucralose appear on a UK label?
Useful label-reading detail
Sucralose or E955 will be named directly in the ingredient list, usually alongside “sweetener” in the category name. It is not the same molecule as sucrose (table sugar) despite the similar name, and the amount used is small because it is intensely sweet; a label cannot show the milligram dose.
How it is classified
A chlorinated intense sweetener. It is not a polyol and is not FODMAP-relevant at typical doses; it is not an emulsifier.
Why amount matters
Sucralose is used at milligram-level doses because it is roughly 600 times sweeter than sugar. EFSA’s acceptable daily intake is 15 mg/kg body weight per day, and EU dietary exposure estimates sit below that limit for all population groups.
Evidence by study type
What do studies show about Sucralose?
What was studied: A 2019 double-blind trial (34 men, 780 mg/day for 7 days) found no phylum-level microbiome change; a 2022 open-label trial (40 adults, 48 mg/day for 10 weeks) found shifts in some bacterial groups and an altered insulin response.
What it cannot tell us: Different doses, durations, blinding and small sample sizes make the two trials hard to compare directly, and neither followed participants long enough to show a clinical health outcome.
Sources2019 sucralose no-change trial2022 sucralose dysbiosis trial
What human studies show about Sucralose
Human trial results on sucralose and the gut microbiome conflict. A 2019 double-blind controlled trial in 34 healthy men found 780 mg/day of sucralose for 7 days did not change the gut microbiome at phylum level or affect glucose control. A 2022 open-label trial in 40 healthy adults found 48 mg/day of sucralose for 10 weeks shifted some bacterial groups and increased the insulin response to a glucose test. The two studies differed in dose, duration, blinding and design, which likely explains at least part of the disagreement.
SourcesEFSA sucralose re-evaluation2019 sucralose no-change trial2022 sucralose dysbiosis trialUK approved-additives listGreat Britain food-additive register
What animal or laboratory studies suggest about Sucralose
Some animal studies report gut microbiota and metabolic changes from sucralose, generally at doses higher, proportionally, than typical human intake; these findings support further human study rather than settling the human question. Sucralose is largely unabsorbed and excreted essentially unchanged, so any microbiome effect would need to occur through direct contact with gut bacteria rather than systemic absorption. There is ongoing debate about whether high-temperature cooking can degrade some sucralose into chlorinated by-products, though evidence at food-relevant conditions is limited.
SourcesEFSA sucralose re-evaluation2019 sucralose no-change trial2022 sucralose dysbiosis trialUK approved-additives listGreat Britain food-additive register
What we still do not know about Sucralose
Whether sucralose meaningfully changes the gut microbiome or metabolism at typical human intake, and for whom, is unresolved. Reviews describe the evidence as inconsistent rather than settled in either direction.
Great Britain regulatory context
E955 is authorised in Great Britain. EFSA’s most recent re-evaluation (2026), described as its most comprehensive review of sucralose in around 20 years, reconfirmed the existing acceptable daily intake and found no safety concern at current authorised uses. It did not extend approval to a proposed new use in fine bakery wares, citing a data gap partly related to whether high-temperature baking affects sucralose’s structure.
SourcesEFSA sucralose re-evaluation2019 sucralose no-change trial2022 sucralose dysbiosis trialUK approved-additives listGreat Britain food-additive register
Common questions
Questions people ask about this label
Does sucralose damage the gut microbiome?
The evidence is genuinely mixed. Some controlled human trials find shifts in specific bacterial groups or metabolic markers, while others find no change at the broad phylum level. Reviews describe the overall picture as inconsistent, not a settled harm finding.
Sources2019 sucralose no-change trial2022 sucralose dysbiosis trial
Is sucralose absorbed by the body?
Most ingested sucralose is not absorbed and passes through the gut largely unchanged before being excreted. This is part of why it contributes negligible calories, and it is also why researchers look for a direct gut-contact mechanism rather than a systemic one when studying its effects.
SourcesEFSA sucralose re-evaluation
Has sucralose been reassessed as a food additive recently?
Yes. EFSA published a re-evaluation of E955 in 2026, its most comprehensive review of sucralose in around 20 years. It reconfirmed the existing acceptable daily intake and found current authorised uses safe, while declining to approve an extension to fine bakery wares pending more data.
SourcesEFSA sucralose re-evaluation
Does heating sucralose create harmful by-products?
There is ongoing scientific debate about whether high-temperature cooking can degrade some sucralose into chlorinated compounds, which is part of why EFSA asked for more data before approving sucralose in baked goods rather than treating it as settled. At typical drink and cold-food uses, this heating question does not apply.
SourcesEFSA sucralose re-evaluation
References
Sources used for this page
- EFSA FAF Panel (2026), Re-evaluation of sucralose (E 955) as a food additive
- Thomson et al. (2019), Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults
- Méndez-García et al. (2022), Ten-week sucralose consumption induces gut dysbiosis and altered glucose and insulin levels in healthy young adults
- Food Standards Agency, Approved additives and E numbers
- Food Standards Agency, Register of food-additive authorisations for Great Britain
Written and evidence-checked by the GutGuard editorial team. We favour official UK guidance, systematic reviews and primary human research, and label animal, laboratory and exploratory findings clearly. Read our editorial method.