This is not actually true. Both amphetamine and methamphetamine are neurotoxic: methamphetamine is both more potent and less neurotoxic per 'dose'.

http://www.ncbi.nlm.nih.gov/pubmed/22289608

Also, as an anecdote, I have received d-amphetamine by prescription and have taken Desoxyn about five times. They're not that different, Desoxyn is subjectively 'cleaner'.

I stick to caffeine though, and roughly half a Modafinil every two weeks. Amphetamine is just not my friend. Your mileage may vary.