Understand Your Methylation & MTHFR

Methylation is a chemical reaction your body performs billions of times a second. A small molecule — a methyl group — gets attached to something else, and that switches a process on or off. It matters because it sits underneath several things at once. Methylation converts folate into the form your body can use. It clears homocysteine, an amino acid that builds up when the pathway runs slowly. It helps produce and break down neurotransmitters including dopamine and serotonin. It supports the liver's detoxification pathways, and it regulates which genes are switched on. When the pathway runs less efficiently, it doesn't cause one specific illness. It shifts what your body needs — often more of a particular form of a nutrient, or less exposure to something it clears slowly. That's what genetic methylation testing is for: not a diagnosis, but a map of where your own pathway is likely to need support.

MTHFR is the best-known methylation gene, and two variants come up most often: C677T and A1298C. C677T reduces the activity of the MTHFR enzyme, which can leave homocysteine higher than it would otherwise be. A1298C is less well understood and may also reduce activity. You can inherit one, both, or neither. But MTHFR sits in a chain. MTR and MTRR handle the B12-dependent step immediately after it. CBS governs where homocysteine goes next. COMT affects how quickly you clear dopamine and adrenaline. MTHFD1 and PEMT sit alongside them. Two people with identical MTHFR results can have quite different methylation profiles because of what the rest of the chain is doing. If you only want the two MTHFR variants, our MTHFR Check covers them. If you want the pathway, the Genetic Methylation Test includes MTHFR along with 91 other genes — so there's no need to order both.

We want to be straight with you about this, because methylation testing is easy to oversell. What it gives you: your genotype at 113 positions across 92 genes, colour-coded and explained, with the research behind each one referenced. It's a stable, one-time map of how your body is likely to handle folate, B12, homocysteine and several other processes. What it doesn't give you: a diagnosis. A methylation variant is not a disease, and having one doesn't mean you'll develop anything. Most people carry some. MTHFR testing isn't routinely offered on the NHS, and it's specifically not recommended for investigating inherited clotting risk — if that's your question, speak to your GP rather than ordering this. Genetic results are also most useful next to what's actually happening in your body right now. Homocysteine, B12 and folate are blood markers that show whether the pathway is currently under strain. Genes tell you the tendency; those markers tell you the reality.