With this decision, Ipsen would save hundreds of thousands of mice suffering in the tests. So far, all batches of botulinum toxin are still tested in LD 50 tests on mice, in which the poison is injected into the animals' abdominal cavities in order to determine the dose at which 50% of the animals die of respiratory paralysis.

International animal welfare organisations have been calling for the abolition of this test for years, along the lines of Allergan, who received approval for an in vitro method for testing their batches in 2012. However, the approval was given only for Allergan's products BOTOX® (onabotulinumtoxin A) and BOTOX®Cosmetic. The procedure cannot directly be applied to other products, as each product has different concentrations, associated molecules and carrier substances.

Ipsen did work with the German manufacturer Merz on developing an in vitro test, but this venture suffered a setback in 2012. This summer, Merz cautiously announced that it expects to have an in vitro test of its own toward the end of 2014.