When you swallow the capsule, the peptide is delivered directly to the site of the injury (the stomach and intestinal lining)
Department of Defense Operation Supplement Safety bulletin reviewing BPC-157s regulatory status and the risks of unregulated consumer products is a useful read
Start where you're comfortable
American Journal of Clinical Nutrition, 115(4), 787-789
This will include a medication review and physical exam to identify treatable causes of tinnitus or danger signs in the nature of the tinnitus, such as if it is sudden onset, pulsatile, unilateral or asymmetric, or accompanied by hearing loss or other neurological changes
The synthetic form, cyanocobalamin, is the form most commonly used in supplements and foods, as it is cheap to produce