Refrigeration at 2-8C is recommended to minimize degradation, and for extended storage, freezing may be considered
But these are all classic red flags that your body is running on empty
If you are concerned about getting every last unit out of a vial, they are worth the small extra investment
Skin samples were fixed with 4% paraformaldehyde, embedded in paraffin, and sectioned for H&E, Masson, and immunohistochemical staining
Some researchers report slightly longer periods, up to 6 weeks, but we err on the side of caution
The dose needed depends on how severe the deficiency is and the persons health