Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that works as a catalyst for important biochemical reactions in your body. It converts vitamin B9 (folate) into methyl-folate, which is essential for a process called methylation. Although people suffering from MTHFR mutations may have problems synthesizing Glutathione, there is nothing that we can find in the literature that would support a decrease in absorption of HINNAO Glutathione, as it is already assembled Glutathione and doesn’t therefore rely on methylation to “assemble” it.