There are many double blinds test showing no or little effect.
This is not to say that a placebo can not be useful, as at the end of the day if you feel like the pain is less, then it effectively is, it's just that you need to know that it's your mind playing tricks on you, and it's just that "thing" this may be something that gets your mind to play those tricks, rather than the "thing" it's self. Whether this be a glucose pill or acupuncture.
Word of warning.
Acupuncture is generally believed to be a placebo.
http://www.dcscience.net/?p=45
There are many double blinds test showing no or little effect.
This is not to say that a placebo can not be useful, as at the end of the day if you feel like the pain is less, then it effectively is, it's just that you need to know that it's your mind playing tricks on you, and it's just that "thing" this may be something that gets your mind to play those tricks, rather than the "thing" it's self. Whether this be a glucose pill or acupuncture.