Medium concern

Sucralose

Splenda · E955 · "0-calorie sweetener"

A chlorinated synthetic compound about 600 times sweeter than sugar. Marketed for decades as "made from sugar, so it tastes like sugar" — but the manufacturing process replaces three hydroxyl groups with chlorine atoms, making it a fundamentally different molecule.

Why we flag it

Sucralose was long considered the safest of the artificial sweeteners — the body absorbs only a small fraction of it, and most passes through unchanged. The picture has gotten more complicated. A 2023 study in the Journal of Toxicology and Environmental Health found that a metabolite produced when sucralose breaks down (sucralose-6-acetate) caused DNA damage in human cells and was detectable in blood after consumption, prompting the authors to call for safety review.

Other research has linked sucralose to gut microbiome disruption, glucose intolerance in healthy adults, and the formation of harmful chlorinated compounds when heated (a real issue, since people bake with it). The FDA still considers sucralose safe at current intake; the European Food Safety Authority began a re-evaluation in 2024.

Where you'll find it

Anywhere "no sugar," "zero calorie," or "diet" appears on the front of a package:

What to look for instead

Naturally derived sweeteners carry a much cleaner research track record:

The cleanest label signal: "no artificial sweeteners" plus a short, recognizable ingredient list. USDA Organic certification prohibits sucralose entirely.