ghk-cu overdose How Tightens Loose Skin: Evidence & Protocols GHK-Cu Peptide Therapy: The Definitive

Although adverse reactions to intravenous, intramuscular or subcutaneous injection of 0.9% benzyl alcohol are not known to occur in man, experimental studies of small volume parenteral preparations containing 0.9% benzyl alcohol in several species of animals have indicated that an estimated intravenous dose up to 30 mL may be safely given to an adult without toxic effects

I think it's probably both

Not all B12 supplementation methods are created equal

Pylori Antibody Screening Hormone Replacement Consultation DOT Exams Other Medical Services Available Any other medical treatments necessary are accessible to a patient with an additional charge that is determined by the medication or technology, at the cheapest possible price

Age and Lifestyle Factors Age and lifestyle are important considerations when evaluating the need for B12 shots

And different downstream effects mean a different side effect profile