This restriction is in place because methylene blue is a potent drug with significant physiological effects and risks (like serious drug interactions and contraindications), so its use must be professionally supervised
doi: 10.1073/pnas.1306285110 Hardy, Margaret C., Daly, Norelle L., Mobli, Mehdi, Morales, Rodrigo A
and oxidation via the cytochrome, P450-dependent, mixed-function oxidase enzyme pathway to form a reactive intermediate metabolite, which conjugates with glutathione and is then further metabolized to form cysteine and mercapturic acid conjugates
Intramuscular Injections for Wellness Optimization Glutathione IM Injections- The Powerful Antioxidant Glutathione is a powerful antioxidant naturally produced by the liver and found in every cell of the human body