You can, but not everyone absorbs oral supplements well, especially those with digestive or absorption issues
B12 injection are great
At Perfect B, the standard GHK-Cu dosage is 1 mg per day (4 units on an insulin syringe) for days 1-15, escalating to 2 mg per day (8 units) for days 16-30
ROBINS-I A Tool Assessing Risk Bias Non-randomised Studies Interventions 355, i4919
MOTS-c is a mitochondrial-derived peptide that activates AMPK, the same metabolic switch exercise and fasting flip, improving insulin sensitivity, mitochondrial function, and metabolic flexibility
Veganism, for example, is more common in todays society and with B12 normally being obtained from liver, milk, eggs, fish, oysters and clams a B12 injection is an alternative method of ensuring your body still receives these essential vitamins