The supplement industry aggressively promotes “methylated” vitamins as superior for absorption, but scientific evidence largely fails to support this claim. While these vitamins, particularly methylated folate and B12, do exist in an active form, the human body is typically efficient at converting standard vitamins into usable forms.
The Science Behind Methylation
Methylation involves adding a methyl group (CH3) to a vitamin molecule. Proponents argue this pre-converted state enhances bioavailability, meaning the body absorbs it more easily. However, experts like Dr. Kevin Klatt at the University of Toronto state, “There is no recommendation from any authoritative health body to supplement with methylated versions of these vitamins for the general public… ”
The appeal centers on the MTHFR gene, which controls folate conversion. Some individuals carry mutations that slow this process, potentially increasing cardiovascular risks. However, even for those with MTHFR variants, studies haven’t proven methylated folate (5-MTHF) is superior. Klatt adds, “…None of these claims has supportive evidence from trials. “
Folate and B12: The Details
Two common methylated forms are methylfolate (5-MTHF) and methylcobalamin (B12). Methylfolate is the active form of folate, vital for brain health and cancer prevention. Yet, the body efficiently converts folic acid (standard folate) into 5-MTHF when you consume folate-rich foods or supplements. Absorption is optimized by taking folate on an empty stomach, regardless of form: with food, only 85% gets absorbed.
Similarly, methylcobalamin is the active form of B12, but the body easily converts cyanocobalamin (another B12 form) into its usable state. Research shows no significant absorption difference. Klatt emphasizes there’s little “biological rationale ” for the general population to choose methylated B12.
Risks and Considerations
Both folate and B12 are water-soluble, minimizing toxicity risks from high doses. However, excessive folate can mask B12 deficiency symptoms. Additionally, some 5-MTHF formulations degrade with oxygen and heat, raising concerns for pregnant individuals. Stability data for alternative 5-MTHF forms remains limited.
The Bottom Line
For most people, methylated vitamins offer no measurable advantage over their standard counterparts. Dr. Rachel Kopec of The Ohio State University concludes, “If we’re talking about somebody who’s consuming a supplement over weeks at a time, the data doesn’t suggest that there’s really one advantage of one form over another. ” Moreover, methylated vitamins tend to be more expensive, while folic acid remains the only form proven effective in preventing developmental issues during pregnancy.
If you suspect vitamin deficiencies, consult a healthcare professional for personalized dietary or supplementation advice.
