Beta blockers such as propranolol decreases your heart rate and blood pressure because one of its most common uses is for cardiac dysfunction. However, propranolol has been shown to immensely help performance anxiety because it decreases your sympathetic system (fight or flight) by reducing your heart rate and blood pressure. I don’t know about you guys, but when I start stuttering or blocking, it’s because I’m feeling especially anxious and nervous about speaking and I always have the physiological signs that go with it such as really tense muscles, pounding heart, feeling really hot, hands getting really sweaty, etc. These are also all of the physiological changes when your body is in fight or flight mode, so my body views speaking to people as a form of danger (because I have social anxiety and fear judgment from others and embarrassment.) If propranolol can decrease all of these physiological signs, then I have no doubt I’d feel much more calm and relaxed which would probably greatly reduce my stutter. I’ve never tried propranolol but I’ve worked in psychiatry before and seen how patients with intense fear/anxiety around public speaking or performances (such as music recitals) praise this medication as significantly changing there life.