Its not legally available through licensed pharmacies
There is no comparison between vitamin injections and oral supplements

Vitamin B12 There is four types of parenteral Vitamin B12 available: Cyanocobalamin 100 mcg/ml and 1000 mcg/ml best used as IM to prevent rapid loss via kidneys Hydroxycobalamin IM (compounded 1000 mcg/ml or more) known as long acting B12 (binds better to plasma proteins than cyanocobalamin) Methylcobalamin IV (compounded 1000 mcg or more up to 5000 mcg/ml) Adenosylcobalamin IV Common dose is 1000 mcg IM or IV Vitamin B12 as hydroxycobalamin is synthesized exclusively by microorganisms and is found in the liver of animals bound to protein as methylcobalamin = metabolically active form of Vitamin B12 Hydroxycobalamin is a chelator of cyanide and is used in cyanide poisoning Hydroxocobalamin is most generally used for vitamin B12 replacement therapy and is considered the drug of choice for vitamin B12 deficiency by the Martindale Extra Pharmacopoeia (Sweetman, 2002) and the World Health Organization (WHO) Model List of Essential Drugs

The injections are easy to administer (and painless) and Im noticing a lot more energy within myself
[10] [16] Whilst similar specific guidance does not yet exist for GLP-1 receptor agonists, clinical vigilance regarding nutritional status is prudent, especially in patients experiencing significant weight loss or gastrointestinal symptoms
This product is not intended to diagnose, treat, cure, or prevent any disease.