Erythritol has been marketed for years as the “good guy” among sweeteners — a natural sugar alcohol found in small amounts in fruits, promoted as zero-calorie, safe for blood sugar, and gentle on digestion. It appears in diet sodas, keto snacks, baked goods, energy drinks, chewing gum, and countless “healthy” treats that promise sweetness without the guilt.

But new research suggests this sweetener may be doing something unexpected behind the scenes: potentially weakening the very barrier that protects the brain.

A study from the University of Colorado has uncovered evidence that erythritol may disrupt the blood–brain barrier — the brain’s tightly controlled security system — and may contribute to processes linked to blood clotting and stroke. While the findings come from laboratory experiments rather than human trials, they add to a growing body of research suggesting erythritol may not be as harmless as once believed.

Let’s break down what this means, why scientists are paying attention, and what it could mean for everyday consumers.

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The Brain’s Border Patrol: Why the Blood–Brain Barrier Matters

The blood–brain barrier (BBB) is one of the body’s most impressive security features. Its job is to act like a microscopic border patrol, allowing nutrients, hormones, and oxygen to enter the brain while blocking toxins, pathogens, and random molecules that would cause chaos if they slipped through.

This barrier is made up of tightly sealed cells lining tiny blood vessels in the brain. These cells communicate with neighboring neurons, immune cells, and chemical messengers to keep the whole system balanced.

When the blood–brain barrier is damaged or weakened:

• harmful chemicals can leak into brain tissue
• inflammation can spike
• neurons can become stressed
• blood clots are more likely
• risk of stroke increases

So, anything that affects the BBB — even slightly — gets scientists’ attention.

What the New Study Discovered

The researchers looked at what happens when erythritol interacts with the cells that make up the blood–brain barrier. Their findings revealed several red flags.

1. Increased Oxidative Stress

Erythritol triggered oxidative stress inside BBB cells.

Oxidative stress is like the biological version of rust. When harmful molecules build up faster than the body can neutralize them, cells become damaged. Over time, oxidative stress can:

• weaken blood vessels
• interfere with normal cell communication
• promote inflammation
• increase vulnerability to stroke and heart disease

This alone would be concerning, but the study found more.

2. Disrupted Molecular Balance

Blood vessels in the brain rely on a delicate mix of chemical signals — nitric oxide, endothelin, and other regulatory molecules — to stay open, flexible, and responsive.

When erythritol was present, these molecules fell out of their usual balance. In simple terms:

• vessel relaxation became harder
• blood flow became less stable
• clot formation became easier

A small shift like this may not be dangerous in the short term, but over time, it can add strain to the vascular system.

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3. Interference With Natural Clot-Dissolving Systems

The body has built-in mechanisms to break down blood clots before they become dangerous. Erythritol seemed to interfere with some of these processes.

This means:

• tiny clots may linger longer
• the body may struggle to clear blockages
• risk of ischemic stroke — where a clot blocks blood flow to the brain — may increase

Even minor problems in this system can snowball into serious complications.

Why This Isn’t Just a Lab Curiosity

You might wonder: if these findings are from cells in a dish, not humans, is it worth worrying about?

The key point is that this study lines up with other research on erythritol in real people.

In 2023, a large human study found that people with high levels of erythritol in their blood had a much greater risk of:

• heart attacks
• blood clots
• strokes

While that study didn’t prove erythritol causes those events, the connection was strong enough that many scientists took notice.

The new study adds a missing piece: a biological explanation for how erythritol might influence the body in ways that raise cardiovascular risk.

It’s not proof, but it’s a compelling clue.

Why Erythritol Is Everywhere

Understanding the concern also means understanding why erythritol became so popular:

• Zero calories
• Doesn’t spike blood sugar
• Doesn’t cause cavities
• Often labeled as “natural”
• Works well in keto and low-carb diets
• Tastes very similar to sugar

Food companies love it because it’s easy to use, tastes good, and helps products appeal to health-conscious consumers.

The problem is that the amount people consume today is far beyond what humans ever got naturally from fruit. The body isn’t used to such high levels — especially daily, sometimes in several products at once.

How Erythritol Behaves Inside the Body

Erythritol is absorbed into the bloodstream very quickly — faster than many other sweeteners. What makes it stand out is that the body doesn’t metabolize it. Instead:

1. You eat it.
2. It enters your bloodstream almost unchanged.
3. Your body eventually flushes it out through urine.

But while it’s circulating in the blood, it interacts with tissues and cells — including those making up the blood–brain barrier.

This means erythritol has plenty of time to influence vascular health, especially in people who consume it often.

The Bigger Picture: Sweeteners and the Brain

This isn’t the first time artificial or low-calorie sweeteners have raised concerns.

Previous research has linked various sweeteners to:

• altered gut bacteria
• increased cravings
• metabolic changes
• headaches
• disrupted glucose tolerance

But the idea that a sweetener might affect the blood–brain barrier is much newer — and more alarming — because the BBB plays a role in conditions such as:

• Alzheimer’s disease
• multiple sclerosis
• neuroinflammation
• cognitive decline

If a sweetener subtly erodes this barrier over years, there may be long-term neurological consequences we haven’t fully mapped yet.

So… Should You Stop Using Erythritol?

Not necessarily. The research is still early, and scientists aren’t calling for bans or telling people to panic.

However, the evidence so far supports a middle-ground approach:

• Reduce heavy daily use.
• Be mindful of products that contain multiple sweeteners.
• Rotate with other natural options like small amounts of honey or fruit-based sugars.
• Avoid relying on erythritol as a primary sugar replacement.

For people with heart disease, clotting disorders, or a history of stroke, extra caution may be especially wise.

A Reminder That “Natural” Doesn’t Mean “Risk-Free”

Erythritol is often advertised as clean, plant-based, and harmless. But cyanide is also natural. So are poison ivy and volcanic ash. “Natural” is not the same as “safe under constant, high exposure.”

The reality is simple:

• humans never consumed erythritol in high doses until very recently
• long-term effects are still being discovered
• early signs suggest the need for caution

The sweetness it provides may not be the problem — it’s the assumption that unlimited use comes without consequences.

Where the Science Goes From Here

Researchers say the next step is clinical trials on humans to determine:

• how erythritol affects the blood–brain barrier in the real world
• what levels are safe or unsafe
• whether certain people are more vulnerable
• how long-term consumption changes vascular health