However, so far, no significant adverse effects have been consistently reported
Daily 1,000 mcg Dosing in the Initial Phase In the first one to two weeks, daily injections of 1,000 mcg are given
(PubMed) Delle Chiaie R, Pancheri P, Scapicchio P
It also has a solid research footing, with early lab work characterizing this growth-hormone fragment and how it behaves (Ng et al., 2000, Hormone Research)
The standard NHS protocol for B12 deficiency typically involves hydroxocobalamin 1mg intramuscularly three times a week for two weeks (if there's no neurological involvement) or on alternate days until no further improvement (if neurological symptoms are present)
Full evaluation of an AHK-Cu protocol requires at least six months, preferably a year