The headline was everywhere this week.

"World's Most Popular Herbicide Causes Convulsions in Worms" from Science Alert and The Daily Mail.

"Popular weed killer linked to animal convulsions," from the Courthouse News Service.  "Study: Roundup is Toxic at Levels 300x Less than Common Exposure," from Laboratory Equipment. "Glyphosate Linked to Seizure-Like Behaviour In Nematodes Study" from Horticulture Week.

Based on the headlines, you might expect the experiment to have been fairly simple. Get some worms. Spray the worms with Roundup. Observe seizures.

However, the paper that led to these headlines differs significantly from what they might lead you to assume. What it potentially tells us about glyphosate exposure in humans requires some unpacking.

Scientists at Florida Atlantic University were keen to add on to CDC research showing that glyphosate has been found in 80% of urine samples. So they got some roundworms found in soil. And they subjected them to Roundup, glyphosate, and a chemical from a family of chemicals originally used in the British formulation of Roundup but subsequently banned.

Then they shocked them.

That's right. The researchers themselves used electricity to cause the convulsions. "Scientists Cause Convulsions In Worms" is maybe less sexy than putting glyphosate in there. It might be a semantic point, but the headlines saying glyphosate caused the convulsions are inaccurate at best.

That's especially true because researchers observed worms swimming in the exposure solutions pre-electrocution and detected no difference between them and worms swimming in saline, according to the paper.

Researchers found that worms exposed to glyphosate and Roundup took longer to recover from their scientifically induced seizures than those in a control group. For those who might wriggle at the thought of electrocuting worms, don't worry. Researchers also used an anti-epileptic drug to treat (some of) the worms, which resulted in recovery faster than those worms not treated.

The conclusion researchers drew from this is that glyphosate and Roundup somehow interfere with the transmission of GABA, a neurotransmitter believed to play a role in anxiety and depression in humans, and used to allow the worms to move in smooth, s-shaped curves. They concluded this because the medication they used allows for the expression of GABA, and it stopped the seizures.

Remember also that glyphosate can cross the blood-brain barrier, according to researchers at Arizona State University.

So let's recap what the worm study shows:


1.) glyphosate or roundup exposure exceeds 0.02% in the brain


2.) An electrical stimulus applied to your whole body causes seizures


3.) There's a higher-than-normal chance that the seizures will last longer than they otherwise would, with an even smaller chance that they might not stop within five minutes.

Good to know. Here's a rough approximation, put another way:


1.) You spill ketchup on your lap


2.) You happen to be walking by a zoo where a bear has escaped


3.) There's a higher-than-average chance that the bear will go for you, and an even smaller chance the bear will select you over a passerby holding a hamburger and wearing a tee shirt reading "Eat Me!"

Remember, bears love ketchup, and they can't read. Play it safe.

Other writers point out that unless you happen to be walking around your field with a cattle prod shocking worms, the odds that glyphosate will make a difference to the worms are small.

While it's clear the study shows glyphosate can impact brain function in nematodes, it doesn't necessarily show that it definitely will impact brain function in nematodes, let alone people.

That's something to keep in mind for the inevitable next set of headlines.