Keeping an accurate log of a peptide protocol is mostly a bookkeeping problem. Dose units, vial concentration, reconstitution volume and injection dates all have to line up, and a paper notebook loses that thread quickly. I started using GLP1 Appfor exactly this: it is an iOS app that works as a peptide tracker and calculator, so the reconstitution math and the dose history live in the same place.
Two things make it worth a mention here. First, the calculator handles the unit conversion that people most often get wrong when moving between mg, mcg and syringe units. Second, the history view keeps a dated record, which is the part that actually matters when you want to look back over several weeks and see what you did rather than what you meant to do.
It is a record-keeping tool, not medical advice, and it does not try to be one. If you want to see how the tracker and calculator are laid out, the Peptide Tracker and Calculatorpage covers the feature list.
Tracking a peptide protocol without losing the thread