Health, safety, and regulation
Sucralose has been accepted by several national and international food safety regulatory bodies, including the U.S. Food and Drug Administration (FDA), Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives, The European Union's Scientific Committee on Food, Health Protection Branch of Health and Welfare Canada, and Food Standards Australia-New Zealand (FSANZ). Sucralose is one of two artificial sweeteners ranked as "safe" by the consumer advocacy group Center for Science in the Public Interest. The other is Neotame.[10][11][12] According to the Canadian Diabetes Association, the amount of sucralose that can be consumed on a daily basis over a person’s lifetime without any adverse effects is 15 mg/kg/day.[13][14]
"In determining the safety of sucralose, the FDA reviewed data from more than 110 studies in humans and animals. Many of the studies were designed to identify possible toxic effects, including carcinogenic, reproductive, and neurological effects. No such effects were found, and FDA's approval is based on the finding that sucralose is safe for human consumption." For example, McNeil Nutritional LLC studies submitted as part of its U.S. FDA Food Additive Petition 7A3987 indicated that "in the 2-year rodent bioassays...there was no evidence of carcinogenic activity for either sucralose or its hydrolysis products..."[15]
Safety studies
Results from over 100 animal and clinical studies in the FDA approval process unanimously indicated a lack of risk associated with sucralose intake.[4][16][17][18] However, some adverse effects were seen at doses that significantly exceeded the estimated daily intake (EDI), which is 1.1 mg/kg/day.[19] When the EDI is compared to the intake at which adverse effects are seen, known as the highest no adverse effects limit (HNEL), at 1500 mg/kg/day,[19] there is a large margin of safety. The bulk of sucralose ingested is not absorbed by the gastrointestinal (GI) tract and is directly excreted in the feces, while 11-27% of it is absorbed.[2] The amount that is absorbed from the GI tract is largely removed from the blood stream by the kidneys and eliminated in the urine with 20-30% of the absorbed sucralose being metabolized.[2]
Thymus
Some concern has been raised about the effect of sucralose on the thymus. A report from the Australian National Industrial Chemicals Notification and Assessment Scheme (NICNAS) cites two studies on rats, both of which found "a significant decrease in mean thymus weight" at high doses.[20] The sucralose dose which caused the effects was 3000 mg/kg/day for 28 days. For a 150 lb (68.2 kg) human, this would mean an intake of nearly 205 grams of sucralose a day, which is equivalent to more than 17,200 individual Splenda packets/day for approximately one month. The dose required to provoke any immunological response was 750 mg/kg/day,[21] or 51 grams of sucralose per day, which is nearly 4,300 Splenda packets/day. After evaluation of these data and other toxicological findings, the NICNAS report concluded that sucralose does not pose a hazard to public health.[20]
I'll take the scientific studies and the FDA approval opinion.
Eating "17,200 packets/day" of anything is dangerous.