Vyvanse converts to dextroamphetamine, it acts on dopamine and norepinephrine systems in the brain. It’s prescribed for ADHD. It causes neurons to release more dopamine and norepinephrine into the synaptic cleft (the space between neurons). It also blocks their reuptake, meaning these chemicals stay active longer in the brain. it’s a dose-dependent balance, so low to moderate doses of Vyvanse enhances fluency for those with ADHD; high doses could worsen stuttering. When the drug wears off, dopamine levels fall back to baseline, but often below baseline temporarily, because your brain has been releasing extra during the whole time you were taking the medication. The crash in dopamine to below your normal baseline impacts your speech even worse until everything stabilises again back to your natural dopamine *tone*. This “dopamine dip” is one of the biggest reasons stuttering gets worse after Vyvanse leaves your system.