MTHFR, Undermethylation and Overmethylation

As we have discussed in our other posts, the MTHFR gene is responsible for the MTHFR enzyme which regulates the methyl cycle (aka all of the important functions our body needs to survive). When this gene is mutated it can lead to the methyl cycle functioning abnormally. These abnormal functions can be related to highly efficient methylation or poor methylation.


As the name suggests, undermethylation is when there is too little methyl. Undermethylation is related to perfectionism, high levels of self-motivation and desire for high achievement. I bet you’re thinking ‘wow, how can I be an undermethylator?’…but before you get a head of yourself, undermethylation has also been associated with negative health issues such as:

  • Addiction/Addictive personalities
  • Competitive nature
  • Delusions
  • Obsessive compulsive disorders
  • Inner tension
  • Ritualistic behaviour
  • Social isolation
  • Phobias
  • Higher levels of allergies
  • Low serotonin
  • Heavy metal toxicity
  • Depression

Undermethylation can also result in a number of nutritional deficiencies including low levels of calcium, methionine, vitamin B6, magnesium, zinc, homocysteine and SAMe.


Overmethylation is the opposite of undermethylation. It is when the MTHFR enzyme produces too much methyl. Overmethylation has been associated with:

  • ADHD
  • Depression
  • Anxiety
  • Frustration/Anger
  • Low motivation
  • Paranoia
  • Self-harm
  • Food sensitivities
  • Sleep disorders

Overmethylation can also lead to elevated levels of serotonin (which is not always a good thing), low levels of histamine, low levels of zinc and high levels of copper.

Testing for Under or Overmethylation

As with anything, it’s important not to rely on Dr Google, or the internet, for diagnosis. MTHFR gene mutations and Under or Overmethylation can be tested by your doctor or by 23andMe.

Treatment for Under or Overmethylation

Once you have been medically diagnosed with a MTHFR gene mutation and a methylation problem, you can look to nutritional supplement regimes for treatment. The goal of these supplement programs is to offset the effects of the Under or Overmethylation. Addressing the methylation imbalance is a good start to improving your health.