Acupuncture usually good for 3-4 days to one week. It is suggested to have acupuncture at least once per week. Some cases may need 2-3 times per week.
Returning patient treatments can last about 45 minutes to 1 hour.
In terms of how long Acupuncture needles are left in the body, on average it is left for 20min to 45min. This differs from each acupuncturist.
The needle are usually retained 30-60 minutes.
There is no way to predict how long the effects will last. It depends on the reason for your pain, the underlying structure involved (muscles and spine) and the method of acupuncture used.
A single treatment is unlikely to produce total resolution of a health issue. As the treatments accumulate the results last longer. A neuro surgeon once told one of my patients that after a course of treatment (anywhere from 6-12) acupuncture is a bit like taking a vicodin that last for weeks. That was a great way to describe it. Wouldn't it be great to get to the point where you only needed one pain pill (or acupuncture session) ever few weeks?
I'm just going to give you some generalities here, whatever provider you're seeing may be slightly different. That being said, an initial intake usually runs 90 minutes and will include treatment time (i.e. time on the table with needles inserted to treat whatever your complaint may be). A followup treatment usually runs 60 minutes with a few questions up front to determine how the previous treatment worked and what has changed for you followed by treatment time. A community session typically runs 20-30 minutes after a very short set of questions/diagnoses.
Different practitioners may vary from these times slightly, but what I've outlined above is fairly typical.