Botox injections are making it more difficult to smile than ever before, thanks to statistics recently published by the European Commission (EC) regarding the use of animal experimentation.

Nearly 90,000 lab mice are used each year in the European Union alone to test batches of Botox before they can be used on humans, according to the journal Nature. That number has increased from 33,000 mice in 2005.

The EC report singled out Botox testing as a major reason that animal experimentation persists at sustained levels in the EU despite the fact that it has been reduced in many other fields. Currently, every single batch of Botox must be safety tested on mice before it can be injected into the face of a human.

Overall, the report indicated that over 12 million animals are tested on for scientific purposes in the EU each year, the largest proportion of which are research animals used in fundamental biology studies. More than two thirds of the animals were used by five of the EU's member states — France, the UK, Germany, Spain and Italy.

The report estimated that as many as 9 million more animals may be used for research by 2018. The primary reason for the increase is the recent passage of the EU's REACH legislation (Registration, Evaluation, Authorization and Restriction of Chemical substances), which is a new EC regulation on chemicals and their safe use.

Of course, the regulations apply to humans, not to research animals. Companies working to meet the new safety standards are expected to increase their use of animal experimentation as a result.

Transgenic mice are among the animals most likely to see an increased work load. The number of mice used has increased by more than 690,000 between 2005 and 2008 for all experimental purposes. Rats and rabbits are also common research animals, though their use has decreased since 2005 in a number of key research fields, such as with skin and eye irritation tests. The report noted that alternative methods of toxicity testing can be credited for the reduction.

No great apes are used for animal experimentation in the EU in accordance with recognized law, but monkeys are still allowed.