Subcutaneous administration of material often causes minimal pain or discomfort, provided the material is non-irritant, has a near-neutral pH, and is not excessively hypertonic or hypotonic.
The most usual site for injection is over the shoulders, into the loose skin over the neck, but other sites with loose folds of skin can also be used, for example over the flank. When repeated doses of material are needed, varying the site of injection can help reduce the likelihood of local skin reactions.
It is not usually necessary to try to sterilize the skin with antiseptics – their use is almost always ineffective and they simply prolong the duration of restraint needed and may cause additional disturbance to the animal.
As with all injection sites, using a new needle for each animal, and injecting fluid that is at body temperature will reduce any discomfort caused by the procedure.
As with other routes, if repeated injections of material are needed, consider alternatives such as use of minipumps.