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MTHFR and Male Fertility: What Your Genotype Means and How to Support Reproductive Health

Infertility affects many men and can arise from a mix of lifestyle, environmental, and genetic factors. One gene that influences fertility is MTHFR. This gene helps process folate, a B vitamin that matters for DNA repair, methylation, and healthy sperm development. Variations in MTHFR can change how well the enzyme works and may affect sperm count, motility, and DNA integrity, especially when diet or lifestyle do not support optimal folate metabolism.

Why MTHFR Matters for Sperm Health

  • Folate metabolism is central to methylation. Methylation supports DNA repair and gene expression in sperm development.
  • Reduced MTHFR enzyme activity can impair folate conversion to active forms needed for methylation and nucleotide synthesis.
  • When enzyme function is lowered, risks can include lower sperm count, reduced motility, and increased sperm DNA fragmentation, particularly under nutrient-poor or high-stress conditions.
  • Environmental exposures, smoking, heavy alcohol use, poor diet, and high stress can make the effects of MTHFR variants more pronounced.

General Recommendations to Support Fertility

Regardless of your genotype, these lifestyle and nutrition steps support sperm health and hormone balance.

  • Eat folate-rich whole foods. Focus on leafy greens, legumes, asparagus, avocado, and citrus.
  • Choose active B vitamin forms when supplementing. Methylfolate and methylcobalamin are preferred over folic acid for many people with MTHFR variants.
  • Consider a B-complex supplement that includes methylfolate, methylcobalamin, vitamin B6, and riboflavin to support MTHFR enzyme function.
  • Fill your plate with antioxidants. Berries, nuts, dark leafy greens, colorful vegetables, and green tea help protect sperm from oxidative damage.
  • Avoid tobacco and limit alcohol. Both increase oxidative stress and can reduce sperm quality.
  • Limit exposure to environmental toxins. Reduce contact with pesticides, heavy metals, plastics with BPA, and industrial solvents when possible.
  • Manage stress. Regular sleep, relaxation practices, mindfulness, or therapy support hormonal balance and recovery.
  • Stay active with moderate exercise. Aim for regular activity but avoid excessive endurance training that can stress the body and reduce testosterone.
  • Monitor relevant labs. Homocysteine can indicate folate pathway status. Work with your healthcare provider to interpret results and adjust nutrition or supplements.

Genetic Interpretations

Below are interpretations based on the rs1801131 genotype. Use the expand and collapse sections to view the interpretation that matches your result. Remember that genetics is only one part of fertility, and lifestyle, environment, and medical history also matter.

Two effect alleles: GG (reduced enzyme function)

What this means

If you have the GG genotype at rs1801131, you carry two copies of the effect allele. This variant reduces MTHFR enzyme activity by about 20% and is associated with up to a 28% higher risk of male infertility compared with people without this change. Reduced enzyme activity can impair folate metabolism and methylation processes that support DNA repair and sperm quality. The impact is often greater when nutrition is poor or stress is high.

Practical steps

  • Consider a B-complex supplement with 400 to 800 mcg methylfolate and 250 to 1000 mcg methylcobalamin, plus B6 and riboflavin. Discuss dosing with your healthcare provider.
  • Prioritize folate-rich foods such as spinach, kale, lentils, chickpeas, and avocado rather than relying on folic acid fortified foods alone.
  • Include riboflavin sources such as dairy, eggs, and lean meat to support MTHFR enzyme function.
  • Eat antioxidant-rich foods daily. Add berries, walnuts, dark leafy greens, and brightly colored vegetables to meals.
  • Quit smoking and limit alcohol to support sperm quality and reduce oxidative stress.
  • Minimize exposure to toxins. Use protective equipment if you work with chemicals and choose low-tox personal care and household products.
  • Practice stress reduction techniques such as sleep hygiene, mindfulness, and moderate exercise to lower stress-related impacts on sperm.
  • Talk to your provider about checking fasting homocysteine and relevant B vitamin levels to guide supplementation and monitor response.
One effect allele: GT (slightly reduced enzyme function)

What this means

If you have the GT genotype at rs1801131, you carry one copy of the effect allele. This is associated with a modest reduction in MTHFR enzyme function and an approximately 28% higher risk of male infertility compared with people without the G allele. Even a single effect allele can influence folate metabolism and methylation, which support DNA repair and sperm quality. The effects may become more noticeable under poor nutrition or high stress.

Practical steps

  • Consider a B-complex supplement that contains methylfolate and methylcobalamin rather than folic acid. Typical methylfolate doses range from 400 to 800 mcg; methylcobalamin 250 to 1000 mcg based on clinician advice.
  • Eat a diet rich in natural folate. Include leafy greens, legumes, citrus, and whole grains as part of balanced meals.
  • Focus on antioxidant foods and get regular servings of fruits, vegetables, nuts, and seeds.
  • Avoid smoking and minimize alcohol intake to protect sperm quality.
  • Limit exposure to environmental toxins and practice safe food handling to reduce chemical exposures.
  • Incorporate stress management and moderate exercise into your routine to support hormonal health and sperm production.
  • Consider measuring homocysteine if advised by your healthcare provider to refine supplementation and dietary plans.
Zero effect alleles: TT (typical enzyme function)

What this means

If you have the TT genotype at rs1801131, you carry two copies of the non-effect allele. This genotype is associated with typical MTHFR enzyme function and a lower risk for infertility related to this specific genetic variant. Your body should efficiently process folate for methylation and DNA repair, which supports healthy sperm production and quality.

Practical steps

  • Your genetic profile at this position is favorable, but lifestyle still matters. Continue eating folate-rich whole foods such as leafy greens, legumes, and avocados.
  • Maintain adequate B vitamin intake through diet or a balanced multivitamin. If supplementing, standard B vitamin forms may be appropriate unless otherwise advised.
  • Keep antioxidant-rich foods in your diet and avoid smoking and excessive alcohol to preserve sperm health.
  • Manage stress, get regular moderate exercise, and limit environmental toxin exposure to support fertility.
  • If you or your partner are facing infertility, consider comprehensive evaluation including semen analysis, lifestyle review, and discussion of targeted testing with a healthcare provider.

When to Talk with a Healthcare Provider

  • If you are trying to conceive and concerned about fertility, schedule an evaluation with your clinician or a fertility specialist.
  • Consider lab tests such as semen analysis, homocysteine, and B vitamin levels if recommended by your provider.
  • Discuss supplement choices and doses with your clinician, especially if you have other health conditions or take medications.

PlexusDx provides education about genetic predispositions only. This information is not medical advice. Always consult your healthcare provider before starting new supplements, making major dietary changes, or making decisions related to fertility and medical care.