An alternative: Measuring urine levels of xanthurenic acid following intake of a high dose of tryptophan
A notable portion of the published literature on this compound has specifically examined its relationship to visceral adipose tissue, making it a frequent reference point in targeted-fat-region research
These can include hives and redness at the injection site
For use in the treatment of vitamin B12 deficiency, and for poor growth rates and general unthriftiness in young animals when associated with the above deficiency

Chan School of Public Health: "Vitamin B12." Inflammatory Bowel Diseases: "Prevalence of and risk factors for vitamin B(12) deficiency in patients with Crohn's disease," "Vitamin B12 deficiency in inflammatory bowel disease: prevalence, risk factors, evaluation, and management." MedlinePlus: "Cyanocobalamin Injection." National Health Services: "Hydroxocobalamin," "Treatment -Vitamin B12 or folate deficiency anaemia Contents," "Vitamin B12." Nutrition Reviews: "How prevalent is vitamin B(12) deficiency among vegetarians?" Surgery for Obesity and Related Diseases: "Vitamin B12 deficiency in patients undergoing bariatric surgery: preventive strategies and key recommendations." The American Journal of Clinical Nutrition: "How common is vitamin B-12 deficiency?" The American Journal of Gastroenterology: "Vitamin B12 deficiency in untreated celiac disease." Top B12 Injections Who Get Them, How Quickly They Work Related Articles 22 Healthy Foods High in B VitaminsAny deficiency of B vitamins can lead to various health conditions

They address deficiencies linked to fatigue, anemia, and neurological issues