Half Syringes of Filler for Sale? Safe?

    Some patients doggedly insist that they only want a part of a syringe, but I refrain from selling portions of a syringe. 

Doctors do not sell ½ syringes of filler nor does Allergan supply them as such. Most people would require at least one syringe to properly treat an area. That being said, one syringe of filler can be decanted to another syringe to treat two patients. I would only do this if they were friends/relatives and came to our office together for their injections so that the stability of the product is preserved. 6 months is questionable.You should perhaps ask the MD how they are preserving the half syringe.

Obviously it doesn't make sense to buy a half of a syringe that isn't already packaged by the manufacturer as such, like a 0.4mL for example because you don't know what you're buying. If you are visiting a reputable plastic surgeon, you shouldn't have any reason to feel suspicious about their practices. If you aren't sure whom you're seeing, do your research first.

Once the seal on the syringe is broken, sterility is no longer assured.  "Splitting a syringe before using it" is another bad practice.  There is no practical way to do this and maintain an appropriate level of sterility.  For this reason, the Medicis and Allergan do make smaller syringes although most patients need a full milliliter or more of filler.  Ask yourself, in 6 months, when you do back for the other half of that syringe, how likely is it that you will get your syringe and not Mrs Jones syringe?  Unless your doctor is running a certified tissue bank, it is very improbable that have secure procedures to avoid this type of accident.

This is a bad idea.  Don't use this filler - you have no idea about the sterility.  Throw it away.  I can not recommend this approach at all.