*sighs* I don't even know where to start.

Meth should not have draino, or battery acid, or any chemicals in it other than methamphetamine hydrochlride. Yes, many of the chemicals used to synthesize meth are flammable and/or toxic, but none of them should make it into the final product. Most perscription drugs were likely synthesized usng some chemicals that are toxic.

Methapmphetamine is stronger than amphetmine due to the the addition of a methyl group, which makes it harder for your body to break down the drug, so it sticks around longer.

Amphetamines in general are quite harsh on your body. They cause your body to burn stored energy, while preventing it from doing the things it needs to do to replenish that energy, like eating and sleeping.

Heroin is very easy on your body, the drug it's self is no more harmful than weed. The problem lies it's stong potential for addiction, and the lifestyle most people once they become addicted.