MTHFR Activity
MTHFR converts synthetic folic acid into the active methylfolate your body uses. Reduced function is common, affecting up to 40% of people. If you're one of them, standard prenatal vitamins and fortified foods won't cut it. Methylfolate supplementation bypasses the bottleneck entirely.
What this measures
How your DNA shapes MTHFR activity.
MTHFR is the enzyme that converts folate from your food into the active form (5-methyltetrahydrofolate) your body uses for methylation — the process that builds neurotransmitters, regulates DNA expression, and clears homocysteine. It sits at one of the most consequential nodes in the methylation cycle.
C677T and A1298C are the two variants most people have heard of, and they often show up together. Carriers of one C677T copy are associated with enzyme activity around 65% of typical. Two copies, around 30%. The A1298C variant shifts the picture again, and the surrounding methylation-cycle genes (MTR, MTRR, BHMT, COMT, CBS) all interact with what MTHFR can do.
Methylated folate (5-MTHF) bypasses the conversion step entirely. So does folate-rich food — leafy greens, asparagus, beans. Synthetic folic acid, the form added to fortified flour, is the form the enzyme has to work hardest to process. Alcohol depletes folate. B12 status matters because the cycle stalls without it.
The reason your aunt swears by methylfolate and your friend says regular folic acid works fine isn’t preference. It’s biochemistry. Knowing which version of MTHFR you carry — and which related variants came along for the ride — changes what you’d actually want on your plate, and what to ask your provider about.
MTHFR Activity is one specific finding in this system. Your Genomic Lifestyle Optimization Report shows where your variants place you on the detoxification pathways spectrum — and what you can do about it: it renders as a dark card with a color marker calibrated to your variants, opening with the gene mechanism and closing with a practical, mechanism-led recommendation.
Want to see what a real Mosaic dark card looks like? Walk through a sample report →
In context
Phase II: the 5-insight cluster.
MTHFR Activity is one finding in a tightly-related cluster. Mosaic sequences the other 4 alongside it so you see the whole biology — not an isolated data point.
Questions people ask
About MTHFR Activity.
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