Ask to watch the syringe being filled from the bottle, and make sure the bottle is labeled "Botox" and contains a hologram with the word "Allergan" (the manufacturer) on it. Any doctor can inject Botox (yes, even a gynecologist or ophthalmologist), but it's wise to get it only from a plastic surgeon, dermatologist, or dermatologic surgeon who uses it regularly, says Dr. Lee A. Gibstein. They know facial anatomy best and can give you the safest and most believable results."

I did find it kinda stupid to base the judgement of authenticity of the poison by the price.

Oh, yes, we would want believable results.