can b12 injection give you diarrhea Compounded Hydroxocobalamin (Vitamin B12) Are There Drawbacks To Vitamin
Description
Some B vitamins are known by other names such as biotin (vitamin B7), folate or folic acid (vitamin B9), and riboflavin (vitamin B2)

The mid-to-late follicular phase is characterized by a moderately pro-inflammatory milieu that supports follicular maturation and vascularization (e.g., elevated IL-8 and soluble IL-6 receptor), with estradiol promoting a Th2 bias and natural killer (NK) cell cytotoxicity

doi: 10.1186/s10194-016-0688-8
If NNMT expression or activity is high, then, NA might not be salvageable to form NAD +