What Is Erythritol and Why Scientists Are Worried

A Sugar Substitute in Almost Everything

Walk down the sugar-free aisle of any grocery store and erythritol is hard to avoid. This four-carbon sugar alcohol sits at the heart of popular keto sweeteners, protein bars, diet drinks, sugar-free gum, and baked goods marketed as healthier alternatives to sugar. Approved as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, erythritol delivers about 60–70 percent of the sweetness of table sugar with virtually zero calories and no effect on blood glucose levels.

For years, that profile made it the darling of the low-carb world. But a growing body of research is raising serious questions about what erythritol does once it enters the bloodstream.

How Erythritol Is Made

Erythritol occurs naturally in tiny amounts in fruits such as watermelon, pears, and grapes, and in fermented foods like wine and cheese. The quantities are far too small for commercial use, however. Industrial erythritol is produced by fermenting glucose—typically derived from corn starch—with yeast or fungi. The process yields a white, crystalline powder with a mild cooling sensation on the tongue, which is why it is especially popular in chewing gum and hard candy.

Unlike other sugar alcohols such as xylitol or sorbitol, erythritol is almost entirely absorbed in the small intestine and excreted unchanged in urine, which is why it rarely causes the digestive distress associated with its chemical cousins. That clean metabolic path, paradoxically, may be part of the problem.

The Cardiovascular Red Flag

In 2023, a landmark study published in Nature Medicine by researchers at the Cleveland Clinic found that people with the highest blood levels of erythritol were roughly twice as likely to suffer a major cardiovascular event—heart attack, stroke, or death—over a three-year follow-up period compared with those who had the lowest levels. The finding was replicated in both American and European patient cohorts.

A follow-up intervention study, published in Arteriosclerosis, Thrombosis, and Vascular Biology, showed a specific mechanism: when healthy volunteers drank a single erythritol-sweetened beverage, their blood erythritol levels surged roughly 1,000-fold and remained elevated for days. That spike made platelets—the blood cells responsible for clotting—significantly more reactive, increasing the potential for dangerous blood clots.

New Evidence: Brain Blood Vessels at Risk

Research published in 2025–2026 from the University of Colorado Boulder added another layer of concern. In laboratory experiments on brain microvascular endothelial cells—the cells lining tiny blood vessels in the brain—erythritol disrupted multiple protective systems simultaneously:

• Reduced nitric oxide production while boosting endothelin-1, causing blood vessels to constrict rather than relax
• Triggered oxidative stress, flooding cells with free radicals and weakening antioxidant defences
• Blocked tissue plasminogen activator, the body's natural "clot buster," potentially leaving clots free to cause strokes

The researchers cautioned that these experiments were conducted on isolated cells, not inside living brains, and that further studies in animals and humans are needed to confirm the effects.

What Consumers Should Know

Erythritol remains legally approved in the United States, the European Union, and most other markets. Regulatory agencies have not changed their guidance, and some nutrition scientists argue that observational data linking blood erythritol levels to heart risk may be confounded—people with metabolic disease naturally produce more erythritol internally.

Still, the National Institutes of Health has acknowledged that the accumulating evidence "highlights the need for further study of erythritol's long-term risks." The Mayo Clinic recommends that people with existing cardiovascular risk factors discuss sugar-substitute choices with their doctors.

For now, the science is evolving. Erythritol may yet prove safe for most people in moderate amounts—or it may join a long list of food additives whose safety profile looked better before rigorous testing caught up. Either way, the assumption that zero calories automatically means zero risk is one worth questioning.