Methylation cycle

Set of interconnected biochemical reactions that transfer methyl groups (CH3) throughout the body, regulating hundreds of vital processes: neurotransmitter synthesis, gene expression, hepatic detoxification, glutathione production and homocysteine regulation. The cycle relies on several essential nutritional cofactors: folates (vitamin B9), vitamin B12, vitamin B6, riboflavin (B2) and methionine. Genetic variants such as MTHFR or MTHFD1 can slow certain steps of the cycle, increasing needs for specific cofactors.