Is Botox safe in regards to its ability to cross the blood brain barrier?

Hey there - thanks for the question! Botox has been used since the 70's in medicine. As far as I'm aware there are no proven detrimental CNS effects from botox though some people will get headaches immediately after botox as it begins to work - but this is usually only very temporary.
Hope that helps

Generally, the Botox in injected into the muscle and the effects stay locally.  If it is injected into an artery or vein, it could get into the blood stream.  I am not aware of any post-treatment CNS problems.  However, I advise you to only get injections from a trained medical provider to assure injections are being placed correctly.

There has been no evidence to date that the amount of cosmetic botox normally used can cross the BBB. This, however had been reported in the past when botox was used in large quantities in patients with cerebral palsy.

thank you for your question. Botox is safe neurotoxin that will relax the muscle. It has been approved by Healy Canada and FDA. 
Good luck
Dr Lamia Wassef

Hi, thanks for your question.  While there have been some studies that show that, the crossing is with large amounts of botox that have been administered, such as people with cerebral palsy for muscle spasm.  In the amounts that is used for cosmetic, there is not evidence that it can affect the brain.  In fact, some studies show that it is inactive as it is seen in the distant studies. Look at the millions of treatments that have been performed across the world.  So feel free to use Botox to help your frown!