Weight-loss miracle pills raise questions about their main ingredient

New Scrutiny for Weight-Loss Tablets

Blockbuster weight-loss medications are changing how we tackle obesity. While many people find the expensive injectable versions hard to access, the recent approval of tablet forms could increase availability and demand significantly. However, a study from the University of Adelaide, published in the Journal of Controlled Release, raises concerns about these tablets. It finds that the ingredient salcaprozate sodium (SNAC), meant to enhance absorption, might have harmful effects on our gut and overall health.

This study is the first to systematically examine the impact of repeated SNAC exposure on gut bacteria, function, and metabolic health in living organisms. It involved testing an animal model over 21 days, leading to some concerning findings:

A drop in beneficial gut bacteria that help with fiber breakdown

Lower levels of short-chain fatty acids that protect the gut and help control inflammation

Increased blood markers for inflammation

A rise in liver weight, often linked to low-grade inflammation

Smaller cecum size, which is crucial for fiber breakdown and producing protective compounds

A decrease in a brain-derived protein that’s tied to cognitive issues.

While the study doesn’t definitively say SNAC is harmful, it implies that this ingredient might have effects beyond merely helping semaglutide—an active compound in weight loss drugs—work in a tablet form.

Semaglutide, when injected, directly enters the bloodstream, but in tablet form, it needs SNAC to protect it from digestive enzymes and to facilitate absorption. Without SNAC, oral semaglutide simply wouldn’t be effective.

With the U.S. approving the Wegovy tablet last year, expectations are that it will be a more affordable and convenient option than injections. This means long-term exposure to SNAC may rise significantly.

Globally, around 890 million people, including 160 million children, are living with obesity—about one in eight individuals worldwide. The United States has the highest obesity rate among OECD countries, with 43% of those over 15 affected, while Australia ranks sixth at 31%, surpassing the OECD average of 25%.

In Australia, the demand for drugs such as Ozempic and Wegovy has surged in recent years.

Amin Ariaee, the lead author and a Ph.D. candidate at Adelaide University, emphasizes that understanding the full biological impact of SNAC is essential, especially in addressing any long-term health concerns as oral obesity treatments grow in popularity.

“Obesity is a complex, chronic disease that comes with serious health risks. These medications are indeed effective and are helping many,” says Ariaee. “But as oral versions are increasingly used, we must consider the implications of prolonged exposure to all the pill’s ingredients—not just the active compound.”

Dr. Paul Joyce, a Senior Research Fellow, adds caution to the findings. “It’s crucial to approach these early results from animal studies with care; they reveal significant research gaps,” he notes. “While our findings don’t confirm that SNAC harms humans, they do suggest that this ingredient could have adverse effects other than aiding drug absorption.”

“As these medicines are often taken daily and for extended periods, it’s increasingly vital to assess all elements of these therapies, not only the primary active ingredient,” Dr. Joyce concludes.