A recent (Feb. 2017) article from The American College of Physicians (ACP) presents evidence and clinical recommendations on noninvasive treatment of low back pain. The results are relatively surprising and additionally, acupuncture rates higher in relieving back pain than NSAIDs, steroids or aspirin, and is also safer.
Results can be seen typically between 1 and 6 treatments. Some people may need maintenance a few times a year depending on their case.
The full article is here.