Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

MTRR Gene and Male Fertility: What Your Results Mean and How to Support Sperm Health

Infertility affects many men and can arise from a mix of genetic and environmental factors. One important gene in this picture is MTRR. MTRR helps recycle vitamin B12 into a form your body can use for methylation reactions that support DNA repair, gene regulation, and healthy sperm formation. Variations in MTRR can change the enzyme's efficiency, influence homocysteine levels, and affect DNA methylation in sperm cells. Below is an easy-to-understand guide to what your MTRR genotype may mean and practical steps you can take to support reproductive health.

Why MTRR Matters

  • MTRR supports vitamin B12-dependent methylation processes required for DNA synthesis and repair.
  • Reduced MTRR activity can lead to less efficient methylation, higher homocysteine, and increased risk of DNA errors in sperm.
  • Genetic differences in MTRR do not determine fate. Diet, supplements, lifestyle, and medical care can significantly influence outcomes.

Tests to Consider Discussing with Your Provider

  • Serum vitamin B12 (and active B12 when available)
  • Serum folate or red blood cell folate
  • Plasma homocysteine
  • Basic reproductive evaluation including semen analysis if fertility is a concern

Diet, Supplements, and Lifestyle Recommendations

These recommendations are educational and intended to support methylation and sperm health. Always review changes with your healthcare provider.

Diet

  • Eat methylation-supporting foods: leafy greens, legumes, beans, avocados, beets, and cruciferous vegetables.
  • Include B12-rich foods if you eat animal products: fish, shellfish, beef, poultry, eggs, and dairy.
  • For plant-based diets, prioritize B12-fortified foods and discuss supplementation with your provider.
  • Limit processed foods, excessive sugars, and trans fats which can worsen oxidative stress.

Supplements (discuss with your provider)

  • Methylcobalamin (active B12): commonly recommended ranges for adults are 500 to 2,000 mcg daily when supporting methylation; your provider will tailor dose.
  • Methylfolate (active folate): supports methylation more directly than folic acid in people with impaired methylation pathways.
  • Vitamin B6 and riboflavin (B2): cofactor support for methylation enzymes.
  • Antioxidants: vitamin C, CoQ10, and zinc to reduce oxidative stress and support sperm quality.
  • A complete B-complex may be useful if diet is limited; check interactions and doses with your provider.

Lifestyle

  • Avoid smoking and limit alcohol; both negatively affect sperm quality and can interact with methylation.
  • Maintain a healthy weight through balanced diet and regular exercise; both underweight and obesity can harm fertility.
  • Minimize exposure to environmental toxins and endocrine disruptors (certain pesticides, plastics, heavy metals) when possible.
  • Manage stress through sleep hygiene, relaxation techniques, and mental health support as needed.
Two effect alleles (GG genotype) — greatly reduced MTRR activity

If your result is GG for rs1801394, you carry two copies of the effect allele. This genotype is associated with greatly reduced MTRR enzyme activity. Reduced activity may impair vitamin B12 recycling and methylation, which are important for DNA repair and proper sperm formation.

  • Risk: Research indicates the GG genotype is associated with about a twofold higher average risk for male infertility compared to individuals without this variant.
  • Biological impact: Inefficient B12-dependent methylation can lead to DNA errors in sperm, higher homocysteine levels, and less effective DNA repair.
  • Support strategies:
    • Work with your provider to measure B12, active B12 when available, folate, and homocysteine.
    • Consider methylcobalamin supplementation under medical guidance; doses frequently used for support range from 500 to 2,000 mcg daily depending on needs.
    • Use methylfolate rather than folic acid to directly support methylation pathways.
    • Include B6 and riboflavin as cofactors.
    • Boost antioxidants such as vitamin C, CoQ10, and zinc to protect sperm from oxidative damage.
    • Adopt lifestyle measures: stop smoking, limit alcohol, maintain healthy weight, exercise, and reduce toxin exposure.
One effect allele (AG genotype) — moderately reduced MTRR activity

If your result is AG for rs1801394, you carry one copy of the effect allele. This genotype is associated with approximately an 18% increased risk for male infertility and reflects a somewhat reduced MTRR enzyme efficiency.

  • Risk: Moderately increased risk compared to non-carriers.
  • Biological impact: Somewhat less efficient processing of vitamin B12 can modestly affect DNA methylation and sperm quality.
  • Support strategies:
    • Discuss testing for B12, folate, and homocysteine with your provider.
    • Consider methylcobalamin supplementation (500 to 2,000 mcg daily range) and methylfolate as directed by your provider.
    • Include B6 and riboflavin in your regimen if recommended.
    • Prioritize folate-rich foods such as leafy greens, beans, and avocados.
    • Use antioxidants including vitamin C, CoQ10, and zinc.
    • Maintain healthy lifestyle habits: avoid smoking, limit alcohol, exercise regularly, and reduce processed foods and toxin exposure.
No effect alleles (AA genotype) — typical MTRR function

If your result is AA for rs1801394, you carry two copies of the non-effect allele. This genotype is associated with typical MTRR enzyme activity, supporting efficient vitamin B12 metabolism and methylation.

  • Risk: Generally lower risk for infertility related to this specific variant.
  • Biological impact: Normal methylation support for DNA repair and sperm formation, with usual control of homocysteine.
  • Support strategies:
    • Maintain a balanced diet with foods that supply B12 and folate.
    • Consider routine wellness checks including B12 and folate when clinically indicated.
    • Continue antioxidant-rich foods and healthy lifestyle habits to sustain optimal sperm quality.

Final Notes and Important Disclaimer

This information is educational and intended to help you understand how variation in the MTRR gene may relate to male fertility and what lifestyle, dietary, and testing options can support reproductive health. PlexusDx does not provide medical advice. Always discuss genetic results, testing, supplements, and treatment options with your healthcare provider or a qualified specialist before making health decisions.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Infertility and MTRR rs1801394

What does an MTRR rs1801394 result mean for male fertility?

MTRR helps recycle vitamin B12 into an active form used for methylation reactions that support DNA repair, gene regulation, and healthy sperm formation. If you have the effect allele(s) for rs1801394, enzyme efficiency may be reduced, which can influence vitamin B12-dependent methylation, homocysteine levels, and DNA integrity in sperm. The GG (two effect alleles) genotype is associated with greatly reduced MTRR activity, AG (one effect allele) with moderately reduced activity, and AA (no effect alleles) with typical MTRR function.

What lab tests are commonly recommended to support an MTRR-related methylation and sperm health plan?

To better understand how your MTRR results may be affecting methylation and fertility, providers commonly consider serum vitamin B12 (and active B12 when available), serum or red blood cell folate, and plasma homocysteine. A basic reproductive evaluation may also be recommended, including a semen analysis if fertility is a concern.

How can diet, supplements, and lifestyle support sperm health if my MTRR activity is reduced?

Support centers on improving methylation inputs and lowering oxidative stress. Diet: emphasize methylation-supporting foods like leafy greens, legumes/beans, avocados, beets, and cruciferous vegetables; include B12-rich foods if you eat animal products, or choose B12-fortified foods and discuss supplementation if plant-based. Supplements (only with your provider): methylcobalamin (active B12), methylfolate (active folate), and cofactors like B6 and riboflavin; antioxidants such as vitamin C, CoQ10, and zinc may also be used to reduce oxidative damage. Lifestyle: avoid smoking, limit alcohol, maintain a healthy weight, reduce exposure to endocrine disruptors/toxins, and manage stress and sleep.

What tests can help me learn more about Infertility and MTRR rs1801394?

The Hormone, Thyroid, and Reproductive Health Genetic Test delivers over 85 personalized genetic insights through a comprehensive Hormone & Fertility Genetic Report, explaining inherited tendencies related to hormonal balance, reproductive function, and endocrine signaling. The Mens Hormone and Fertility Health Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.