I did speech therapy (in public school, US) and it helped me tremendously. It truly does depend on your therapist, the ones who were the most dedicated to my journey made the most progress with me. Some just made me watch the kings speech and read out loud. I did it from K-12 and stopped in college (by choice) and started attending mental health therapy which also made a great impact on my stutter. I would recommend speech therapy, but definitely look into specific therapist rather than programs.