MTHFR: What It Means for Your Health and Why a Team Approach Matters

What Exactly Is MTHFR?

If you’ve ever had genetic testing done, you may have come across the letters MTHFR and wondered what on earth they mean. MTHFR (short for methylenetetrahydrofolate reductase) is the name of an enzyme in your body that helps process folate, also known as vitamin B9.

Here’s why it matters: folate needs to be “activated” into a usable form (5-MTHF) before your cells can use it. Once it’s active, it helps your body:

• Repair and build DNA

• Make and balance neurotransmitters (like serotonin and dopamine)

• Support detoxification and antioxidant defense

• Create energy inside your mitochondria (the “batteries” of your cells)

When the MTHFR enzyme doesn’t work as efficiently, this process — called methylation — can slow down, which may affect everything from your energy and mood to your heart and hormone balance.

The Two Most Common MTHFR Variants

Most people have some type of genetic variation in MTHFR. The two most common ones are:

• C677T

  If you carry two copies of this gene change (called TT), your enzyme activity can be reduced by up to 70%. That often leads to higher homocysteine levels, especially if your folate intake is low.

  
  

• A1298C

  This one usually has a milder effect on enzyme function. But if you have one copy of each variant (called compound heterozygous), methylation can be affected more strongly.

It’s important to know that having these variants isn’t “bad” or “dangerous” on its own — but in combination with diet, stress, and other health factors, they can tip the scale toward certain health challenges.

How MTHFR Variants Affect the Body

Because methylation is such a central process, reduced MTHFR activity can ripple through the body in different ways. Some possible effects include:

• Higher homocysteine → a marker linked to inflammation, oxidative stress, and blood vessel health

• Hormone and gene regulation issues → affecting mood, fertility, and menstrual health

• Detoxification slow-down → less glutathione (the body’s “master antioxidant”), making it harder to neutralize toxins

• Neurological symptoms → such as fatigue, brain fog, anxiety, or mood disorders

Not everyone with MTHFR variants will notice symptoms — but for those already dealing with conditions like endometriosis, heart concerns, or chronic fatigue, it may add another layer to the picture.

The Heart Connection: MTHFR and Cardiovascular Risk

One of the best-studied effects of the C677T variant is its link to elevated homocysteine levels. High homocysteine has been associated with:

• Damage to blood vessels

• Increased oxidative stress

• Inflammation inside the arteries

Although recent studies suggest the risk may not be as high as originally believed, many cardiologists and functional medicine providers still keep a close eye on homocysteine. Think of it as another important piece of your heart health puzzle right alongside cholesterol, blood pressure, and lifestyle.

MTHFR and Endometriosis: What’s the Link?

Here’s where things get especially interesting for women’s health. Research suggests that women with the C677T variant may have higher odds of developing endometriosis. Why?

• Less efficient methylation can disrupt hormone regulation.

• Elevated homocysteine and lower antioxidant protection can drive oxidative stress, which is a known contributor to endometriosis progression.

• Inflammation and immune dysregulation may also worsen symptoms like pelvic pain and fatigue.

While MTHFR doesn’t directly cause endometriosis, it may act as a trigger or amplifier in women who are already genetically or environmentally susceptible.

What You Can Do: A Functional Medicine Approach

The good news? There’s a lot you can do to support your body if you have an MTHFR variant. Functional medicine takes a whole-person, team-based approach to help you thrive.

1. Get the right testing

• Homocysteine blood test

• Nutrient panels (B12, folate, B6, etc.)

• Genetic testing, if appropriate

2. Support with targeted nutrition

• Use methylated folate (5-MTHF) instead of standard folic acid

• Add methylated B12 and B6 to keep the methylation cycle running smoothly

• Include antioxidants like NAC, vitamin C, and alpha-lipoic acid for added protection

3. Focus on lifestyle foundations

• Eat a folate-rich diet (leafy greens, lentils, beans, asparagus)

• Prioritize stress management, restorative sleep, and regular movement

• Reduce exposure to environmental toxins (smoking, pesticides, plastics)

4. Build a care team

• Functional medicine provider to guide the big picture

• Gynecologist/endometriosis specialist for reproductive health

• Nutritionist to tailor diet and supplements

• Mental health support when mood or anxiety symptoms are present

The Takeaway

Having an MTHFR variant isn’t something to fear it’s simply a piece of your health blueprint. For some, it may increase cardiovascular risk or worsen conditions like endometriosis. But with the right support, you can work with your genes, not against them.