This one is essential for glucose metabolism
Lifelong intramuscular vitamin B12 replacement is recommended for patients with deficiency caused by autoimmune gastritis, pernicious anaemia, total gastrectomy or terminal ileum resection (Table 4),19 because these conditions irreversibly impair gastrointestinal absorption, making oral B12 unreliable or ineffective even at high doses

A number of studies support NAD + regeneration as a therapeutic strategy to benefit patients with obesity.[27] For examples, natural NAD + precursor activators such as nicotinamide riboside (NR) administered via dietary supplements to high-fat fed mice protected against diet-induced obesity, increased energy metabolism, and improved insulin sensitivity;[41] some of these effects were shown to be mediated by NAD + -dependent SIRT1 activation.[42] Similarly, systemic administration of NMN improved glucose tolerance and diet- and age-related insulin resistant conditions.[43, 44] However, dietary supplemental NAD + precursors (e.g., NR, NMN) require chronic administration and/or very high pharmacological doses to achieve physiologically beneficial enhancements in the NAD + levels, which potentially limit use in humans.[27] It could be predicted that combined administration of sub-maximal doses of dietary supplements and NNMT inhibitors that function as activators of NAD + might produce synergistic improvements in diet-induced obesity, and reduce adverse effects associated with chronic high-dose administration of dietary supplemental NAD + precursors

Hair loss happens because iron is needed for healthy hair follicles
B vitamins help the body handle the effects of stress and keep the immune system healthy, as B-complex vitamins are often used to reduce fatigue and boost mood