Although methamphetamine (MA) and other amphetamines can have similar effects, differences also exist. For example, MA has longer lasting and more toxic effects than amphetamine. This is largely because the N-methyl group that differentiates MA from amphetamine decreases the polarity of the molecule, enabling it to better penetrate the blood brain barrier.
In addition, compared with amphetamine, MA has greater activity as a central nervous system (CNS) stimulant while having less peripheral nervous system and cardiovascular stimulation activity. Another difference between amphetamine and MA is that amphetamine stimulates the CNS indirectly by activating the release of catecholamines and inhibiting their breakdown and storage. In contrast, MA stimulates the postsynaptic catecholamine receptors directly.