MTHFR Testing vs. Cellular Methylation: Which Should You Choose?

At Gene Food, we have been analyzing methylation pathways and synthesizing the latest research for for almost a decade (before it was cool). We have written seriously on the one carbon pathway and walked a sober middle ground between MTHFR fear mongering, which is way overdone and bad for the consumer genomics industry, and coming out and saying MTHFR testing is not necessary, as 23andMe has done.

We don’t take either view.

The thing about MTHFR is that it’s just one piece in a much broader puzzle. It doesn’t cause symptoms.

The scientific research is legitimate, it shows up in the GWAS studies for a reason, but because it affects the metabolism of B vitamins, and because those B vitamins act as a cofactor for the gene’s proper function, the entire topic is prone to reductionism and salesmanship. Oh, you have this “mutation,” take my B vitamin formula and everything will be solved. It rarely works out like that. The overselling of MTHFR breeds a lot of anxiety on forums like Reddit from people who legitimately fret over their status. They take marketing disguised as science from influencers like Gary Brecka at face value, assume it is more important to their overall health picture than it is in reality, and pursue protocols that make them sicker as a result.

Have anxiety? There’s a supplement for that. Energy low? Get this gene tested.

That is the exact wrong way to think about MTHFR and methylation. Methylfolate supplements at mega doses often cause unpleasant side effects.

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A practical approach to MTHFR

It has long been our position that MTHFR status is one gene worth knowing in the broader context of a basket of genes that impact not just B vitamin metabolism, but methylation more broadly. Although the issue has long been on the radar of the wellness community, it wasn’t until about two years ago that Gary Brecka popularized MTHFR testing alongside a handful of other SNPs in the MTR, AHCY, MTRR, and COMT genes. To hear Brecka tell it, your whole life is determined by your status for these five genes. The reality is that these markers are not pathogenic. It’s not one SNP equals one health outcome as you see with cystic fibrosis. These are data points to optimize around as part of a larger strategy, and in many cases, the variants are so common even people who carry the risk alleles operate in perfect health by virtue of another pathway cleaning up any residual risk.

We test for all these markers in our methylation report, but with the launch of our Environment product, now offer a test called Cellular Methylation, which has a focus unique to the market.

Although it is a real issue for homozygous carriers of MTHFR C677T, we aren’t nearly as concerned as Brecka is about folic acid. The fact is that most people can still handle some folic acid in their diets and it’s nowhere close to the boogeyman Brecka makes it out to be. Of course, this doesn’t mean I would be taking a B complex with folic acid. I don’t. I choose methylated forms instead. My point is not that MTHFR genotypes thrive on folic acid. My point is that the marketing has caused us to lose sight of a bigger issue: how methylation is a driver of several biological processes, including detox. We have all seen the lists – methylation affects micronutrient status, heart health, energy, neurotransmitter production, and detox. They’ve been repeated so many times most of us lose sight.

In this post, I am focusing in on one aspect of the methylation pathway, detox.

The issue has never been more critical, as the burden of evolutionarily novel compounds, from synthetic chemicals, to PFAS, to microplastics, and PM2.5, shapes human biology in ways we haven’t seen before.

To put it in plain English, what is the bigger issue in methylation: folic acid or detox? Our view is that while the methylation pathway affects multiple aspects of human health, the detox story has been downplayed. Let me explain how a test like ours works versus a standard methylation test like you might buy from 10X Health or LifeDNA.

Why glutathione should get more methylation focus

I have shared a personal story on the blog about my own MTHFR methylation test results and how they may have affected my homocysteine labs (which were elevated for the first time after moving to SE Michigan). My homocysteine ran high (screenshot from Function Health labs below) despite essentially “normal” MTHFR activity. At the time, my point was to focus on a polygenic approach to MTHFR rather than worrying too much about any one SNP. But after interviewing Dr. Nathan Handley at Thomas Jefferson Health and hearing his views on how elevated homocysteine can be a sign of a system under strain from environmental factors, my views shifted.

We keep framing methylation as a B vitamin issue but that loses sight of the myriad ways this pathway affects health, with one being impaired detox. The evidence is emerging, but has reached the point where it’s worth mentioning.

Let me explain.

A 2024 review in the International Journal of Molecular Sciences notes openly that for slightly elevated homocysteine, it remains unclear whether the slightly elevated concentration of the amino acid is a causative factor or simply a marker of disease.

In other words: when homocysteine is high, it may not be the thing harming you. It may be the thing telling you something else is.

One of those is increasingly thought to be glutathione strain. When you’re under sustained pressure from air pollution, mold, or toxins, your body ramps up the system that produces glutathione to keep up. Homocysteine accumulates in the blood not because something is broken, but because your cells are working overtime to defend themselves.

Why this matters. If homocysteine is partly a readout of how hard your antioxidant systems are working, a high reading isn’t only about folate or B12. It’s a signal that something is draining your defenses — air pollution, mold, alcohol, chronic stress, or anything else that burns through glutathione.

In this way, homocysteine can signal stress – environmental stress.

Unlock Your Personalized Nutrition & Supplement Report

Gene Food uses a proprietary algorithm to divide people into one of twenty diet types based on genetics. We score for cholesterol and sterol hyperabsorption, MTHFR status, histamine clearance, carbohydrate tolerance, and more. Where do you fit?

Get Started

How cellular methylation is different from traditional MTHFR based testing

• Polygenic testing. Brecka-style tests typically focus on a small handful of SNPs — usually MTHFR C677T and A1298C, sometimes a few more in MTR, MTRR, or COMT. Cellular Methylation pulls from the broader GWAS literature on elevated homocysteine, capturing variants across transsulfuration, glutathione synthesis, and detox pathways that the popular tests ignore entirely.
• Broader scope. The Brecka framing treats methylation as a closed loop centered on folate metabolism — bad MTHFR means bad methylation means take methylfolate. Cellular Methylation looks downstream at the transsulfuration arm, where homocysteine is converted into glutathione. That shifts the conversation from “are you methylating folate” to “are your antioxidant and detox systems under strain.”
• Environmental inputs are factored in. Brecka panels stop at the genotype and prescribe a supplement. Cellular Methylation layers in real-time environmental load — Local AQI, PM2.5, NO2 — because these are the pollutants with the strongest evidence for depleting glutathione and driving homocysteine up the transsulfuration pathway.
• Supplements come last. Brecka-style testing leads almost inevitably to a methylated B-vitamin stack — methylfolate, methyl-B12, sometimes TMG. Cellular Methylation pushes the opposite direction: before reaching for a powder, audit what’s burning through your glutathione. Mold in the house, air quality, alcohol, solvents, chronic stress. The supplement is a last step, not the first.
• No folic acid hype, in either direction. The Brecka world oscillates between “folic acid is poison” and “methylfolate is the cure.” Cellular Methylation sidesteps that whole framing. Homocysteine elevation gets treated as a signal of environmental and oxidative load, not as a folate-deficiency story to be solved with the right form of B9.