Can artificial sweeteners in sugar-free foods affect male fertility?

What's actually in it

Artificial sweeteners like aspartame, sucralose, acesulfame potassium, and saccharin are in diet sodas, sugar-free gum, protein bars, yogurt, and thousands of other "low-calorie" foods. They're hundreds of times sweeter than sugar, so manufacturers use tiny amounts. But those tiny amounts add up when you eat and drink multiple sweetened products a day.

What the research says

A 2026 study in Reprod Toxicol tested whether artificial sweeteners affect male reproductive cells. The researchers used both computer modeling and lab experiments to figure out what these chemicals do at the molecular level.

They found that artificial sweeteners target a protein called FGFR1, which plays a key role in sperm development. When FGFR1 gets blocked, the cells that produce sperm don't work properly. The study showed this happening in both cell cultures and animal models.

The damage was dose-dependent: more sweetener meant more harm. The researchers identified FGFR1 as the critical link between sweetener exposure and reduced sperm quality. Without this protein working correctly, sperm counts drop and sperm health declines.

This is early research, and the doses used in the lab were higher than what most people consume in a single day. But for men who drink several diet sodas and eat multiple sugar-free products daily, the cumulative exposure could matter. The study adds to a growing body of evidence that artificial sweeteners aren't as harmless as once thought.