Which nonnutritive sweetener is not widely used due to discouraging studies?

Saccharin is the nonnutritive sweetener that has faced historical scrutiny and skepticism due to various studies suggesting potential health risks. Initially, in the 1970s, it was associated with bladder cancer in laboratory rats, leading to a temporary ban and warning labels. Although further research has largely debunked these connections in humans and the FDA has declared it safe for consumption, the legacy of those studies has continued to affect its popularity among consumers and manufacturers.

In contrast, sucralose, aspartame, and stevia have experienced more favorable reception and are widely accepted in the market. Sucralose, for instance, is perceived as safe and is commonly used in a variety of food products. Aspartame has been thoroughly studied and is deemed safe for most people, with strong regulatory backing. Stevia, derived from the plant Stevia rebaudiana, has gained popularity as a natural sweetener. The safety profiles and general acceptance of these alternatives contribute to saccharin's lesser usage compared to the others.