Having worked in the food industry I know that there is no set method of determining shelf life and it is up to the producer to chose what "use by" or "best before" dates they want to put on their stock, based on their own view of the product under normal conditions
Endocrine Reviews
Hydroxocobalamin A pure form of B vitamin, Hydroxocobalamin is suitable for older individuals who wish to address B vitamin deficiency, for those with inflammatory skin conditions, and for those who desire to improve the condition of their hair, skin and nails

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Each works independently without concern about blood flow interference