The shelf life of a supplement depends on its form, its contents, and how someone is storing it
In summary: This injection covers a broad range of B vitamins but excludes B by design
Needle sizing follows a flipped scale: a higher gauge number actually means a narrower shaft, so a 25-gauge needle is finer than a 21-gauge one
Subcutaneous doses go into the fatty layer beneath the skin think belly, outer thigh, or the back of the upper arm at about a 45-degree angle
Body composition in DIO mice with/without NNMT inhibition showing reduced WAT mass with preserved lean mass relative to diet-matched controls [1,3,4]
Another source of deficiency can be malabsorption issues, where the body is unable to properly absorb B12 from the intestines due to various gastrointestinal disorders