Daily amphetamine dose threshold for significant oxidative damage/neurotoxicity, etc?

[Stimulated]

Just curious what the daily doses of amphetamine must be to cause significant long-term damage, neurotoxicity, oxidative stress, cell damage, receptor damage, etc.?

More importantly, what can be done to protect the body and mind while taking amphetamines frequently (~4-5 days per week)?

I assume that a healthy diet full of antioxidants, regular cardiovascular exercise, and good sleep are all important, as is vitamin supplementation (although I'm unsure of which ones to take).

Thanks!