In a generation where Botox is a procedure as common as wisdom teeth removal, a new botulinum toxin study from the University of Wisconsin in Madison shows that there could be negative health effects associated with the everyday practice.

The new study provides evidence that injected botulinum toxin, which is in popular drug Botox, can actually jump between neurons and hit areas it wasn't intended to treat — adding legitimacy to a fear that began when the product first hit the market. At that time, "the idea was that (the toxins) are safe to use, they stay where they are injected, and you don't have to worry about toxin going to the central nervous system and causing weird effects," said Edwin Chapman, an investigator at the Howard Hughes Medical Institute and professor of neuroscience at the University of Wisconsin Madison. But that may not be the case. 

Back in 2009, the U.S. Food and Drug Administration added a warning to Botox’s prescribing information "to highlight that botulinum toxin may spread from the area of injection to produce symptoms consistent with botulism."

Physicians have also seen some perplexing results from Botox treatment.

"In many cases, after an injection for a disabling spasm of neck muscles called cervical dystonia, there is no change in muscle tone but the patient finds relief and is perfectly happy. That result can't be explained by the local effects,”  Ewa Bomba-Warczak, a doctoral candidate in neuroscience and first author of the study, said.

According to the FDA, these side effects could include "unexpected loss of strength or muscle weakness. ... Understand that swallowing and breathing difficulties can be life-threatening and there have been reports of deaths related to the effects of spread of botulinum toxin."

Chapman and his colleagues’ new study presents clear evidence that the toxin is moving between neurons in a lab dish. The research team has answered a long-standing question about mobility, but also raised several more.

"We have seen that these toxins enter neurons at the injection site, causing the desired local paralysis, but Ewa and Jason have shown unambiguously the existence of a second entry pathway that takes some of the toxin molecules to other neurons," Chapman said — referring to co-author Jason Vevea, a UW-Madison postdoctoral fellow.

Source: Chapman E, Bomba-Warczak E, Vevea J. Botulinum Toxin Study Proves Possibility Of Remote Effects. Cell Reports . 2016.