First: you do not have to test at all
Before anyone spends money, let me say the thing most people writing about MTHFR will not.
You can go by symptoms and skip testing entirely. That is fine.
The intervention is largely the same either way: switch from synthetic folic acid to methylfolate, read your labels, support the pathway with the right cofactors, and see what changes. None of that requires knowing your genotype.
Testing tells you why. It rarely changes what you do about it.
Test if you are curious, if you like data, or if you want to know which specific gene is involved so Parts 3 through 6 mean more to you. Skip it if the cost or complexity would stop you making the change at all. The change is the point, not the paperwork.
How to test your DNA
Step 1: get your raw data
If you have already tested with Ancestry or 23andMe, download your raw data from their website as a .txt file. It is free, and it is already yours.
If you have not tested yet, either is a reasonable starting point.
Step 2: upload it to Genetic Genie
Upload the file to the Genetic Genie Methylation panel.
Please consider making a donation. It is free to everyone because people donate, and it is the clearest report I have found.
Some companies charge up to $600 for this same analysis.
How to read your results
Three symbols. That is the entire vocabulary.
| Symbol | Name | What it means |
|---|---|---|
| +/+ | Normal | Two normal copies, one from each parent |
| +/- | Heterozygous | A variant from one parent |
| -/- | Homozygous | Variants from both parents |
Homozygous generally carries more impact than heterozygous, because both copies of the recipe are affected rather than one.
Sometimes a gene is simply missing from your report. Nothing listed. That is not a result, it is a gap, and it reflects the coverage of your original DNA analysis rather than anything about you.
Two things people get wrong
A page of minus signs looks alarming and mostly is not
These are common variants, not rare disease mutations. Almost everyone has several. Roughly 44% of people carry an MTHFR variant, and nearly everyone has at least one of the five methylation genes affected.
Seeing a column of minus signs does not mean something is badly wrong with you. It means you are a normal human with a normal amount of genetic variation.
A genotype is not a destiny
This is the more important one.
Your genes describe how efficiently an enzyme works. They do not describe what is happening in your body right now.
Two people with identical MTHFR results can have completely different symptoms, or none at all, depending on diet, stress, B12 status, mineral reserves, alcohol intake, medication and everything else going on.
A gene is a tendency. It is not a measurement.
Genes tell you propensity. They do not tell you status.
This distinction shapes everything in Parts 3 through 7.
| A DNA test tells you | A nutrient assessment tells you | |
|---|---|---|
| What it measures | Your genetic tendency | What is actually happening now |
| Does it change? | Never. Same result at 20 and at 70. | Constantly. Changes with diet, stress, illness, supplements. |
| Useful for | Understanding why you respond as you do | Knowing what to do this month |
| Can you act on it? | Indirectly | Directly |
You need both, and they answer different questions.
Your MTHFR result will be the same for the rest of your life. Your actual folate, B12, magnesium and zinc status changed since last year, and will change again. One explains your tendency. The other tells you where you are standing today.
This is why I never treat a genetic report as the answer. It is context. What I act on is what is measurable now — and what is measurable now is the thing that responds when you change something.
A note on privacy
Since this means uploading genetic data, it is worth saying plainly: read the terms of any service you use, including the testing companies themselves.
Consumer genetics companies have changed ownership and policies over time, and your raw data is a permanent, unchangeable identifier that also implicates your relatives, who did not consent.
That is not a reason to avoid it. It is a reason to decide deliberately rather than by clicking through.
Bottom line
Most people have at least one mutation in their methylation pathway.
Whether you test or not, that is a reasonable working assumption. What matters more is what you do next — and Part 3 starts there.
What this article does not tell you
- A genetic variant is not a diagnosis. It describes enzyme efficiency, not disease.
- Consumer DNA tests are not clinical grade. Useful for this purpose, not a substitute for medical genetic testing where that is indicated.
- Mainstream genetics bodies do not recommend routine MTHFR testing, on the grounds that it rarely changes management. Worth knowing, and it is part of why going by symptoms is a legitimate route.
- Missing genes reflect test coverage, not your biology.
- Do not make medical decisions from a consumer genetics report without professional input.
Go deeper
This article covers how to test and read your methylation results. The full picture, including how genetic findings are interpreted alongside actual mineral and vitamin status, is in Dawn's forthcoming book on interpreting the OligoScan, written with Jeff Lioon Jr.
Join the launch list at oligoscanbook.com
References and further reading
- Genetic Genie methylation analysis — free, donation supported
- Ancestry and 23andMe raw data downloads
- National Institutes of Health, Office of Dietary Supplements. Folate Fact Sheet for Health Professionals
- CDC. MTHFR gene variant and folic acid facts
- VIGEO Health Medical Disclaimer
Series navigation
← Part 1: What is the methylation cycle, and why does folic acid matter? → Part 3: MTHFR and sleep
Questions and Answers
Q: How do you test for an MTHFR mutation? A: Download your raw data as a .txt file from Ancestry or 23andMe, then upload it to the free Genetic Genie methylation panel. Some companies charge up to $600 for the same analysis. You can also skip testing and go by symptoms, since the practical intervention is largely the same either way.
Q: What do +/+, +/- and -/- mean on a methylation report? A: +/+ means two normal copies of the gene, one from each parent. +/- means heterozygous, a variant from one parent. -/- means homozygous, variants from both parents. Homozygous generally carries more impact because both copies of the gene are affected.
Q: Is it bad to have a lot of minus signs on a methylation report? A: Not necessarily. These are common variants rather than rare disease mutations. Around 44% of people carry an MTHFR variant and nearly everyone has at least one of the five genes affecting methylation. Several minus signs indicates a normal amount of genetic variation.
Q: Does a DNA test tell you your current nutrient status? A: No. A genetic test describes how efficiently an enzyme works and never changes throughout your life. Actual nutrient status changes constantly with diet, stress, illness and supplementation. Genes explain tendency; nutrient assessment shows what is happening now. The two answer different questions.
Q: Do you need a DNA test to address methylation? A: No. The practical steps are largely the same either way: switch from synthetic folic acid to methylfolate, read labels, and support the pathway with appropriate cofactors. Testing explains why, but rarely changes what you do.