Two facts about these injections matter more than anything on the marketing page: They are compounded, not manufactured under an FDA-approved drug application
While generally considered safe, some individuals may have concerns about synthetic ingredients
A Cochrane review comparing oral and intramuscular B12 found comparable effects on blood levels, and the same principle of good absorption applies to the subcutaneous route
Its often missed, but B12 for stress support is vital for mood swings caused by lack of nutrients
"Microbial production of vitamin B12 by methanol utilizing strain of Pseudomonas species"
[2] High-dose intramuscular administration creates a tissue depot that releases vitamin D slowly over weeks, potentially enabling a single injection to lift serum 25-hydroxyvitamin D levels into the sufficient range in severe deficiency and to potentially support bone mineralisation, neuromuscular function, and secondary hyperparathyroidism reversal while bypassing the gastrointestinal tract