Sucralose at oven heat: the sucralose-6-acetate problem
A 2023 paper found sucralose forms a genotoxic breakdown product at baking temperatures. What that means for the home baker.
Sucralose was approved by the FDA in 1998 on the strength of decades of stability and metabolism data. The accepted picture was that it passed through the body inert and was heat-stable enough for general baking. Both halves of that picture have wobbled in the last few years, and the heat half wobbled hard in 2023.
What changed
Schiffman and colleagues (2023) showed that sucralose, when heated above ~120°C — well within typical baking range — partially decomposes into sucralose-6-acetate. The compound was already known as an industrial impurity from the manufacturing process. The novel finding was that significant additional sucralose-6-acetate forms during baking.
In their assays sucralose-6-acetate was genotoxic to human cells at concentrations achievable from typical dietary exposure, and showed adverse effects on intestinal epithelial cells (gut barrier function).
What the FDA and EFSA have said
Both bodies are reviewing the data. As of writing, neither has updated its sucralose guidance, and industry has disputed the methodology and exposure estimates. The case is not closed.
Practical reading
The actionable concern is heat. Cold uses of sucralose — iced coffee, no-bake desserts, tabletop additions to yogurt — are not directly implicated by this work. Baking is. If you bake heavily with Splenda, the precautionary substitute is allulose (which actually browns properly anyway) or monk fruit.
How we score it
Sucralose drops to 50 / 100 — Moderate — primarily because of the heat finding and the parallel microbiome literature. Cold-use scoring is more lenient. We will adjust as the regulatory review concludes.