Even if you don't have a genetic mutation that compromises your body's ability to manufacture adequate levels of glutathione, life in the modern world means that most of us are probably suffering from glutathione deficiency
Yes, many protocols combine both methods for comprehensive benefits
The study in Molecular Nutrition and Food Research demonstrated that nicotinamide supplementation in mice on a high-fat diet reduced body weight gain, increased energy expenditure, and upregulated genes involved in thermogenesis and fat oxidation, including PPARalpha and PGC1alpha
I was the Captain at Rescue One in San Francisco, one of the busiest firehouses in the United States
There are def still vegan and vegetarian-friendly foods that are rich in vitamin B12 like fermented foods, fungi, and yeast but these may not be as bioavailable (or as easily absorbed)