Most evidence comes from in vitro studies or small human trials, not large-scale randomized controlled trials
Inadequate secretion of intrinsic factor, resulting from lesions that destroy the gastric mucosa (which can be caused by ingestion of corrosives, extensive tumors, and conditions associated with gastric atrophy, such as multiple sclerosis, certain endocrine disorders, iron deficiency, and subtotal gastrectomy) Structural lesions leading to vitamin B 12 deficiency, including regional ileitis, ileal reactions, and malignancies Competition for vitamin B 12 by intestinal parasites or bacteria
Regulatory Framework: Key FDA Guidance Documents for Nasal Sprays The foundation of nasal spray testing requirements in the United States is established by two primary FDA guidance documents, both from the Center for Drug Evaluation and Research (CDER): FDA CDER 2002 Nasal Spray and Inhalation Solution, Suspension and Spray Drug Products Chemistry, Manufacturing and Controls Documentation (CMC Guidance): Defines the CMC documentation requirements for new drug applications (NDAs) and abbreviated new drug applications (ANDAs) involving nasal spray and inhalation drug products
Recommendation: Designs for Health suggests taking 1/2 teaspoon (1 g) of Glutathione Power per day in water or as directed by your health care practitioner
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