The Slushie Ingredient That's Unsafe For Kids

Some childhood experiences feel almost ceremonial: the scraped knee on a playground, the first wobbly bike ride without training wheels, the moment you realize the pool is colder than it looked. And somewhere on that unofficial list is the brain freeze from a slushie gulped down too quickly.

But as harmless as they seem, there’s a growing conversation about whether every slushie is as kid-friendly as it looks. And no, this isn’t the same old story about refined sugar.

In 2025, researchers in the U.K. published a peer-reviewed study documenting 21 kids between the ages of two and seven who required emergency medical care shortly after consuming slushies. The common thread was a specific ingredient called glycerol.

What makes some slushies unsafe?

Glycerol can be found in many slushie formulas, most often in “low sugar” or “no added sugar” varieties. It keeps them from freezing solid and creates that smooth, icy texture. Glycerol (also called glycerin) isn’t generally considered harmful, but in young children, consuming too much in a short period of time can overwhelm the body.

In the cases studied, this led to what’s known as glycerol intoxication. Symptoms included decreased consciousness, low blood sugar, and dangerous shifts in blood chemistry, including a buildup of acid in the body (lactic acidosis). Many of the children became unwell quickly, with warning signs like sudden drowsiness, confusion, or even loss of consciousness.

What parents should know

The findings prompted updated guidance from the U.K.’s Food Standards Agency (FSA). The agency now advises that kids under seven should not consume slush drinks containing glycerol at all. For those aged seven to 10, intake should be limited to no more than one small serving (about 350 ml). The guidance also applies to ready-to-drink slush products and home kits made with glycerol concentrates.

While confirmed cases remain relatively rare, the speed and severity of symptoms make this an issue worth paying attention to, says Dr. Dina Kulik, a paediatrician and owner of Kidcrew in Toronto. One of the challenges for parents is that labelling isn’t always clear, and it can be difficult to tell which products contain glycerol or how much is in a serving.

“Parents should take this seriously,” she says. “While tasty, there are no nutritional or health benefits to these drinks. If there are potential risks, it’s an easy treat to avoid.”

Kulik says kids under eight should indeed stay away from slushies with glycerol. “For older kids, slushies should be an occasional treat, not a regular one, and may be best avoided entirely.”

Are there any nutrients in a slushie?

From a nutrition standpoint, slushies fall into the same category as pop or juice cocktails: something kids can enjoy once in a while, but not a go-to for hydration, says Rosanne Robinson, a registered dietitian and co-owner of Blueprint Nutrition in Waterloo, Ont. Water and milk (or fortified milk alternatives) should make up the bulk of what young kids drink.

She adds that sugar-free options aren’t necessarily a better choice for young kids, since consuming very sweet drinks—whether sweetened with sugar or substitutes—can shape taste preferences over time.

Slushies are still a classic summertime treat and probably always will be. But knowing what’s in the cup could be the difference between harmless brain freeze and something more serious.

FAQs

What makes slushies unsafe for kids? Not all slushies are unsafe for kids, but those containing glycerol can cause serious health risks. Glycerol is often found in sugar-free varieties, but it can be hard to determine the ingredients when you're in a convenience store, at a theme park or ordering from an ice cream truck.

What should you do if your child shows signs of illness after consuming a slushie? Take them to your nearest emergency room or call 911, even if your child is over 8.

Are slushies without glycerol safe for kids? While there are no nutritional benefits and they're high in sugar, yes, slushies without glycerol are generally considered safe.