Satire aside, the meth probably is more or less vegan insofar that meth isn't usually pressed into pill form, which would require a filler. However, there's also compounding pharmacies for people who are genuinely allergic to some parts of a medicine they need. Ie custom pressed medicine. It's not uncommon.

Also, meth and methylphenidate are pretty similar drugs chemically, but you wouldn't want methamphetamine for adhd, too serotonergic. You just want a plain dextroamphetamine. And that is given as an adhd med.

And methylphenidate is abused, quite a lot.

Please don't give poor quality street drugs to your kids, get your amphetamines from a pharmacy, like a responsible adult. Then abuse them.