Buzz
A large portion of the U.S. population carries a less effective variant of the MTHFR gene, a fact TikTok creators often highlight. While this is accurate, many also falsely claim that having this gene variant requires specialized vitamins and that standard vitamins or medications could harm you. Despite these claims being untrue, some influencers have built their entire platforms around such misinformation.
Many TikTokers assert that the MTHFR gene, often humorously referred to as the 'mother f-er gene,' is linked to conditions like autism, ADHD, depression, anxiety, thyroid problems, and more. They promote gene testing, blood vitamin level checks, and personalized coaching to recommend supplements—along with selling you those supplements in abundance.
So, what exactly is the MTHFR gene?
Our bodies house thousands of enzymes, each performing a unique, specialized task, much like a factory worker dedicated to attaching a specific bolt on every car moving down the assembly line. MTHFR refers to both one of these enzymes (a tiny factory worker) and the gene responsible for producing it. We’ll discuss the gene shortly, but first, here’s a brief biochemistry overview—feel free to skim if you’re not in the mood.
Here’s the breakdown: MTHFR, or methylenetetrahydrofolate reductase, is an enzyme that transforms 5,10-methylenetetrahydrofolate into 5-methyltetrahydrofolate. This step is crucial because 5-methyltetrahydrofolate donates a methyl group to homocysteine, forming methionine. Methionine, an essential amino acid, plays a vital role in protein synthesis, supporting growth, cell division, and overall life processes.
This biochemical pathway relies on multiple enzymes, including MTHFR, and involves several vitamins. Vitamin B12 (cyanocobalamin) is also part of this process. The primary molecule MTHFR interacts with is a folate variant, related to folic acid, often referred to as vitamin B9. These vitamins are indispensable, as they fuel critical biochemical pathways like this one.
So, what exactly is the MTHFR gene?
The MTHFR enzyme exists because our bodies produce it, guided by instructions encoded in the MTHFR gene within our DNA. Think of a gene as a recipe—it often contains the blueprint for creating an enzyme or another essential protein.
You can explore the MTHFR entry in the National Library of Medicine’s Gene database here. Located on chromosome 1 in humans (other species have their own versions), this gene is active in various tissues, such as the lungs, thyroid, and spleen. Every individual possesses the MTHFR gene—two copies, in fact—but variations exist between people, meaning yours might differ slightly from mine.
What exactly are MTHFR variants?
Like many genes, MTHFR comes in different versions. While some refer to these as “mutations,” that term isn’t entirely accurate, as it suggests a rare or recent change. Instead, think of MTHFR variants like hair or eye colors—you don’t have a “mutation” for brown hair; you simply have brown hair. Geneticists prefer the term variants to describe these natural variations in genes.
Some MTHFR variants perform their methylation tasks quite efficiently, while others are slightly less effective. However, even the less efficient variants remain functional and rarely lead to significant health problems for most individuals.
TikTok creators often claim that “44%,” “40% to 70%,” or “over 50% of us” carry a gene variant producing a potentially less efficient enzyme. While these statistics aren’t entirely off, pinpointing the exact prevalence is tricky. Some variants only result in reduced enzyme efficiency when paired with another variant or in specific combinations, like two T variants of the C677T SNP versus two C’s or one of each. Additionally, certain variants are more common in specific ethnic groups. Regardless, MTHFR variants are undeniably widespread.
The widespread prevalence of MTHFR variants speaks volumes: if they were as harmful as TikTok suggests, medical professionals would openly discuss them rather than treating them as obscure knowledge. When something impacts half the population, it’s considered, in technical terms, normal.
What TikTok creators claim about MTHFR
Many TikTok videos about MTHFR follow a familiar pattern, similar to those about cortisol: they list a range of “symptoms” from minor annoyances to serious health conditions, followed by recommendations for supplements and treatments.
These MTHFR videos often push viewers toward spending money on DNA or vitamin level testing, with a strong emphasis on purchasing supplements. Convincing people they have MTHFR-related problems and then selling them supplements or coaching to address these non-issues has become a lucrative industry.
According to these influencers, what’s the issue with having an MTHFR variant? One pharmacist claims the gene is responsible for “headaches, inflammation, depression, infertility, digestive issues, heavy menstrual cycles, and thyroid dysfunction.” (Though he doesn’t explain how to determine if your thyroid is malfunctioning.)
A self-proclaimed MTHFR coach claims that conditions like ADHD, anxiety, autism, autoimmune disorders, chronic fatigue, colon cancer, depression, digestive problems, hormonal imbalances, migraines, and thyroid issues are all “symptoms of the MTHFR genetic mutation.”
A naturopath attributes depression, anxiety, and “poor detoxification” to MTHFR variants, suggesting they cause “imbalances” in neurotransmitters.
Numerous heartfelt videos feature individuals sharing their struggles with MTHFR. One mother links her daughter’s speech delays and parasitic infections to the gene, claiming her child’s body is “overloaded with toxins” and that the gene increases her risk of addiction. Another woman describes the gene as something that will “wreck you,” calling it a topic “no one discusses or warns you about.”
Does MTHFR actually lead to health issues?
The gene gained attention due to health-related research. To cut to the chase: nearly all the claims mentioned above lack scientific backing, or the connections are so weak that researchers remain uncertain if they’re even related to the gene.
One health issue associated with the gene is hyperhomocysteinemia, which can arise if you have specific MTHFR variants and a folate deficiency. High homocysteine levels were once believed to increase the risk of blood clots, strokes, and pregnancy complications. However, since the U.S. required folic acid fortification in grain products, the link between MTHFR and these conditions has vanished.
Another concern tied to MTHFR is the potential for neural tube defects in infants. Folate (vitamin B9) is crucial during early pregnancy for proper neural tube development, which forms the brain and spinal cord. In certain populations, individuals with specific MTHFR variants are more likely to have a baby with neural tube defects compared to those with the more efficient gene variant.
Here’s the key takeaway: regardless of your MTHFR variant, supplementing with folic acid addresses the issue. Both the American College of Medical Genetics and Genomics and the American College of Obstetricians and Gynecologists agree that MTHFR genetic testing is unnecessary and that the recommended folic acid intake (400 micrograms on top of dietary sources, totaling 600 micrograms) is sufficient for everyone.
Don’t believe the myth that you require “methylated” vitamins
A recurring claim is that if you have an MTHFR variant (specifically the less efficient ones), you should purchase methylated vitamins, such as 5-methyltetrafolate, instead of standard folic acid. Many influencers further assert that non-methylated forms are “toxic” to you.
The claims escalate quickly. In one video, a podcaster asserts she “literally feels like she’s about to have a stroke” if she consumes non-methylated B vitamins. Another TikToker, affiliated with a genetic testing company, insists that “Methylfolate prevents neural tube defects, while folic acid is ineffective.”
However, this is completely incorrect. Folate appears in various forms in food and the body, with some being more bioavailable and others degrading during cooking or storage. Folic acid is the sole supplement proven to prevent neural tube defects in infants, not methylfolate or dietary folates. An article in the American Journal of Clinical Nutrition underscores this point (bold emphasis added):
Suggestions in both popular media and scientific literature propose replacing dietary folic acid with the more “natural” 5-methyltetrahydrofolate for NTD [neural tube defect] prevention. These claims should be approached cautiously, as
there is no evidence that 5-methyltetrahydrofolate prevents NTDs, whereas folic acid supplementation has been conclusively shown to reduce NTD risks across diverse populations
. Notably, folic acid supplementation in women with the TT MTHFR genotype elevates folate levels beyond the threshold considered maximally protective against NTDs (9).
Do not, under any circumstances, switch to non-standard vitamins based on TikTok advice or recommendations from a nutrition “coach” found on the platform. If you’re pregnant or planning to conceive, ensure you take 400-600 micrograms of folic acid daily. (For those not likely to become pregnant, 400 micrograms of folate equivalents is still advised, though the form—folic acid or another folate—is less critical.)
By the time pregnancy is confirmed, many critical stages of neural tube development have already occurred, making preconception folic acid intake essential. Since 1998, U.S. law has mandated folic acid fortification in grain-based products like bread and cereal, aimed at reducing neural tube defect rates. If you’ve previously had a child with a neural tube defect, consult your doctor about potentially taking a higher folic acid dose.
Oddly, MTHFR TikTok creators also caution against “over-methylation” from taking methylated vitamins. Your body doesn’t balance on a fine line between “over” and “under” methylation, nor is there a universal “methylation” process impacting your entire system. From what I can gather, the concept of undermethylators and overmethylators is a wellness TikTok trend, not something supported by medical research.
MTHFR is not responsible for “stork bites” or other birthmarks
Another TikTok myth is that common newborn features like “stork bites,” “sugar bugs,” and sacral dimples indicate an MTHFR variant and potential health risks. These birthmarks are unrelated to MTHFR, and even if they were, there’s no cause for concern. Keep in mind, MTHFR testing holds no medical value, and knowing your child has an MTHFR variant wouldn’t change any medical recommendations.
