Common adverse effects include: Injection site reactions pain, redness, swelling, or bruising at the intramuscular injection site Gastrointestinal disturbances nausea, diarrhoea, or abdominal discomfort Headache and dizziness particularly following initial doses Skin reactions including rash, pruritus, or acne-like eruptions Flushing temporary redness of the skin Chromaturia red-coloured urine (harmless but can cause concern if unexpected) Less common but more serious reactions include: Hypersensitivity reactions ranging from mild urticaria to anaphylaxis (rare but potentially life-threatening) Hypokalaemia particularly during initial treatment when rapid cell production occurs [5] [16] Temporary changes in blood counts during correction of deficiency Interference with laboratory tests primarily with high-dose IV hydroxocobalamin used for cyanide poisoning, not typically with standard 1mg IM replacement doses Cautions and contraindications: Hypersensitivity to cobalt or vitamin B12 Cyanocobalamin should be avoided in Leber's hereditary optic neuropathy [2] [17] Chloramphenicol may reduce the haematological response to B12 therapy Patients receiving B12 injections outside clinical necessity face unnecessary risks without proven benefit

However, MT-II treatment did not significantly impact social novelty scores in MIA mice
These may include redness or irritation at the injection site
Builds collagen GHK-Cu boosts collagen-building enzymes in the skin
With peptide treatments that are specifically designed to improve recovery, reduce inflammation, support muscle growth, enhance fat loss, and promote longevity from within
Disease Management and Clinical Outcomes, 1(4), 136-141