Serotonin, oxytocin, excess dopamine, and norepinephrine are moderated with acupuncture.

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:75)

Opiod peptides stimulated through acupuncture include ß-endorphin, enkephalin, dynorphin, and orphanin.

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:76)

Changes in connective tissue caused by mechanical stimulation causes a reaction in an area of about 2.5cm from the needling site. 

(Purves D, Augestine G, Fitzpatrick D, Hall W, LaMantia AS, White L. Neuroscience 5th edition. Sunderland, Massachusetts: Sinauer Associates, INC; 2012; 221)

Acupuncture can control visceral (organ) afferent autonomic and sympathetic nerve. 

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:136)

Acupuncture generally regulates a reflex response into its normal direction, as most of acupuncture's effects are on the sympathetic nerves (the exception would be S2, S3, and S4 nerves which innervates the bladder)

Pain control involves the reinforcement of segmental analgesia by activating a generalized system of extrasegmental analgesia. 

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:108)

Opioid Peptide Metabolism and gene expression exponentially increases each time acupuncture is applied

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:89)

Needle retention of more than 45 minutes can be counterproductive as it can stimulate CCK (cholecystokinin) and increase pain after acupuncture. 

(Filshie J, White A. Medical Acupuncture: A Scientific Approach. London, UK: Churchill Livingstone; 2006:77)