Aspartame tested for gene damage in bacteria and mice
What it found
Aspartame did not damage genes in bacteria or mouse bone marrow cells.
The authors say this adds to evidence that it is not mutagenic or genotoxic.
What they found
Animal and lab studies
Bacterial mutation test
Aspartame did not cause mutations in Salmonella typhimurium strains TA100, TA1535, TA98 and TA1537, or in Escherichia coli WP2 uvrA, at any concentration up to 5000 micrograms per plate. This was true with and without a metabolic activation mix.
Mouse bone marrow test
Male mice given aspartame by stomach tube at 500, 1000 or 2000 mg per kg body weight showed no rise in micronucleated polychromatic erythrocytes in bone marrow at 24 or 48 hours. There were also no changes in other bone marrow cell measures.
Early test oddity
In a first range-finding test, two bacterial strains showed a large rise in revertant colonies, up to 10 to 12 times the control. This did not happen again in the main test or the repeat test, and the authors could not explain the first result.
No clinical signs
The mice showed no abnormal clinical signs and no changes in body weight in any dose group.
Studies in people and animals
Comparison with other studies
The results match earlier mouse and rat micronucleus tests by the National Toxicology Program. They do not match one study in Swiss albino mice that reported more micronucleated cells, which the authors say had flaws.
What the authors conclude
“In summary, the present study provides further evidence to support the conclusion that aspartame is non-mutagenic and non-genotoxic”
Also in their conclusions
- They conclude that aspartame is non-mutagenic and non-genotoxic.
- They say their bacterial test is the first to report negative results for aspartame using a strain that detects effects at A-T base pairs.
- Their mouse micronucleus results support earlier in vivo tests done for aspartame's registration.
How it was done
Some earlier studies reported gene-damaging effects from aspartame, but those studies had design problems. The authors wanted to run fresh tests that meet current guidelines and cover a gap in earlier bacterial tests.
They tested aspartame in five bacterial strains at up to 5000 micrograms per plate, with and without a liver enzyme mix. They also gave single doses of 500, 1000 or 2000 mg per kg body weight to male mice and checked their bone marrow cells 24 and 48 hours later.
What it can’t tell you
- These are lab and animal tests. They cannot show what happens in people who consume aspartame.
- The mouse study used single doses, so it does not show what repeated daily intake over years might do.
- The bacterial and mouse tests look at gene damage, not at other possible health effects.
The paper
- Title
- Mutagenicity and genotoxicity studies of aspartame
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Otabe A, Ohta F, Takumi A, Lynch B (2019). Mutagenicity and genotoxicity studies of aspartame. Regulatory toxicology and pharmacology. doi:10.1016/j.yrtph.2018.01.023Free full textPubMed 29408486DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error