Sucralose, aspartame, blood sugar and gut hormones in clinical trials
What it found
Most trials found that sucralose or aspartame did not change blood sugar, insulin or gut hormones.
A few trials did find changes, so the overall picture is mixed.
What they found
Studies in people
Blood sugar levels
Out of all the studies looking at sucralose, 33 found no change in blood sugar. One study found higher blood sugar after sucralose, while 3 studies found lower levels.
Insulin and gut hormones
Most studies found that aspartame or sucralose did not change insulin or gut hormone levels. Only 4 studies reported a rise in the gut hormone glucagon-like peptide 1.
Insulin sensitivity
Three studies reported that insulin sensitivity dropped after consuming sucralose. One trial reported that it went up.
Trials showing effects
Two trials showed that aspartame changed blood sugar, insulin and gut hormone levels. Only a few trials showed similar changes for sucralose.
What the authors conclude
- They note that most trials found no effect of either sweetener on blood sugar, insulin or gut hormones.
- They point out that a small number of trials did find changes, making the overall evidence contradictory.
- They suggest the mixed results come from different methods used across the studies.
How it was done
Sugar-free sweeteners are used to cut calories and carbs, which may help with weight and blood sugar control. But scientists have not settled whether these sweeteners themselves affect how the body handles sugar or releases gut hormones.
The authors gathered and examined existing clinical trials on people who consumed aspartame or sucralose. They looked at results for blood sugar, insulin, insulin sensitivity and a gut hormone called glucagon-like peptide 1.
What it can’t tell you
- We summarised it from the abstract only.
- Because the trials used very different methods, it is hard to draw one clear conclusion about what happens when you consume these sweeteners.
- These trials measured short-term responses, so they cannot show what happens over months or years of regular use.
Who paid
- Authors work at
- University of Manitoba, Canada
The paper
- Title
- Effect of sucralose and aspartame on glucose metabolism and gut hormones
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Ahmad SY, Friel JK, Mackay DS (2020). Effect of sucralose and aspartame on glucose metabolism and gut hormones. Nutrition reviews. doi:10.1093/nutrit/nuz099PubMed 32065635DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error