Nutraceuticals: 

MTHFR Genetic Variants and Chronic Pain

The MTHFR gene (methylenetetrahydrofolate reductase) provides determines an individual’s capacity to make an enzyme that processes folate (vitamin B9) into its active form, methylfolate. Methylfolate is crucial for maintaining DNA and for the manufacturing most of the important neurotransmitters, including dopamine, serotonin, and noradrenaline. These neurotransmitters are responsible for proper brain function, and deficiency of these enzymes can lead to worsening chronic pain, depression, anxiety, and sleep disorders.

Assessing MTHFR gene variants is important primarily because they help identify why a person might have difficulty processing folate (vitamin B9) which can be associated with elevated homocysteine levels. While many people carry these common variants (C677T and A1298C) without any issues, knowing the status can guide personalized health strategies to prevent potential, though often mild, complications.

 

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Definitions and Terms Related to Pain

 

MTHFR Genetic Variants and Chronic Pain

The two clinically relevant MTHFR polymorphisms — C677T and A1298C — interact to produce a spectrum of enzyme activity levels. The categories of “high activity,” “normal activity,” “reduced activity,” and “greatly reduced activity” correspond to specific genotype combinations based on in vitro and in vivo studies. Here is how they correlate:

MTHFR Genotype-Activity Classification

Activity Level

C677T Genotype

A1298C Genotype

Approximate Residual Activity

References

Normal (full) activity

CC (wild-type)

AA (wild-type)

~100% (reference)

[1], [2]

Mildly reduced activity

CC

AC (heterozygous)

~60–68%

[1], [2]

Mildly reduced activity

CC

CC (homozygous)

~52%

[1]

Moderately reduced activity

CT (heterozygous)

AA

~60–65%

[2], [3]

Reduced activity

CT

AC (compound heterozygous)

~36–41%

[1], [2][4]

Greatly reduced activity

TT (homozygous)

AA

~25–35% (“thermolabile”)

[2], [5]

Key Points of Interpretation

  • The C677T variant has the strongest effect on enzyme activity and is the primary driver of clinically significant hyperhomocysteinemia. Homozygosity for 677TT (the “thermolabile” variant) reduces MTHFR activity to approximately 25–35% of normal and is the genotype most consistently associated with elevated homocysteine and reduced serum folate.[6][7][5]
  • The A1298C variant alone has a more modest effect. Homozygosity for 1298CC reduces activity to roughly 52% of normal but, importantly, does not independently cause significant hyperhomocysteinemia in most studies.[1][4][3]
  • Compound heterozygosity (677CT/1298AC) produces an enzyme activity level (~36–41%) similar to that seen in 677TT homozygotes and is associated with elevated homocysteine, particularly when folate status is low.[1][2][4] This is clinically relevant because these two variants are in linkage disequilibrium, meaning compound heterozygosity (one variant on each allele, in trans) is the typical configuration when both are present.[5]
  • Folate and riboflavin dependence: The clinical impact of reduced MTHFR activity is strongly modulated by folate and riboflavin (B2) status. The 677TT genotype is particularly sensitive — homocysteine elevations are most pronounced when folate is low, and riboflavin supplementation can partially restore enzyme function in 677TT individuals because FAD (derived from riboflavin) is the prosthetic group for MTHFR.[8][7]

ACMG Position: The American College of Medical Genetics and Genomics (ACMG) has stated there is a lack of evidence supporting routine MTHFR polymorphism testing  — treatment of hyperhomocysteinemia with B-vitamins is the same regardless of genotype.[5]

If homocysteine remains elevated after B12 normalization despite adequate folate, MTHFR genotyping could help explain persistent hyperhomocysteinemia and guide consideration of riboflavin supplementation, particularly if a 677TT or compound heterozygous genotype is identified.[1][8]

   References

    1. The Effect of 677c–>t and 1298a–>c Mutations on Plasma Homocysteine and 5,10-Methylenetetrahydrofolate Reductase Activity in Healthy Subjects. Chango A, Boisson F, Barbé F, et al. The British Journal of Nutrition. 2000;83(6):593-6. doi:10.1017/s0007114500000751.
    2. The 1298a–>c Polymorphism in Methylenetetrahydrofolate Reductase (MTHFR): In Vitro Expression and Association With Homocysteine. Weisberg IS, Jacques PF, Selhub J, et al. Atherosclerosis. 2001;156(2):409-15. doi:10.1016/s0021-9150(00)00671-7.
    3. A Second Common Variant in the Methylenetetrahydrofolate Reductase (MTHFR) Gene and Its Relationship to MTHFR Enzyme Activity, Homocysteine, and Cardiovascular Disease Risk. Lievers KJ, Boers GH, Verhoef P, et al. Journal of Molecular Medicine (Berlin, Germany). 2001;79(9):522-8. doi:10.1007/s001090100253.
    4. A Second Common Mutation in the Methylenetetrahydrofolate Reductase Gene: An Additional Risk Factor for Neural-Tube Defects?. van der Put NM, Gabreëls F, Stevens EM, et al. American Journal of Human Genetics. 1998;62(5):1044-51. doi:10.1086/301825.
    5. ACMG Practice Guideline: Lack of Evidence for MTHFR Polymorphism Testing. Hickey SE, Curry CJ, Toriello HV. Genetics in Medicine : Official Journal of the American College of Medical Genetics. 2013;15(2):153-6. doi:10.1038/gim.2012.165.
    6. Association of Methylene Tetrahydrofolate Reductase (MTHFR) Gene Polymorphisms With Serum Folate, Cobalanin and Homocysteine Concentrations in Greek Adults. Mazokopakis EE, Papadomanolaki MG, Papadakis JA. Scandinavian Journal of Clinical and Laboratory Investigation. 2023;83(2):69-73. doi:10.1080/00365513.2023.2167232.
    7. Functional Inference of the Methylenetetrahydrofolate Reductase 677C > T and 1298A > C Polymorphisms From a Large-Scale Epidemiological Study. Ulvik A, Ueland PM, Fredriksen A, et al. Human Genetics. 2007;121(1):57-64. doi:10.1007/s00439-006-0290-2.
    8. Combined Marginal Folate and Riboflavin Status Affect Homocysteine Methylation in Cultured Immortalized Lymphocytes From Persons Homozygous for the MTHFR C677T Mutation. Lathrop Stern L, Shane B, Bagley PJ, et al. The Journal of Nutrition. 2003;133(9):2716-20. doi:10.1093/jn/133.9.2716.

MTHFR Genetic Variants and Chronic Pain

The evidence linking MTHFR genetic variants to chronic pain severity or chronification is limited and inconsistent. While MTHFR polymorphisms have been identified in some chronic pain conditions, particularly fibromyalgia and migraine, there is no established evidence that MTHFR variants contribute to the transition from acute to chronic pain. The American College of Medical Genetics and Genomics (ACMG) explicitly states there is insufficient evidence to support MTHFR polymorphism testing for most clinical indications.[1]

 

MTHFR variants and pain

The relationship between MTHFR variants and pain is indirect and mechanistically plausible but not strongly established by direct clinical evidence. The available data suggest several pathways through which reduced MTHFR activity — primarily via hyperhomocysteinemia and impaired methylation — could influence pain sensitivity, central sensitization, and pain-related comorbidities.

   1. Homocysteine is a Direct Pain Sensitizer (Peripheral and Central)

The most compelling mechanistic link involves homocysteine triggers NMDA receptors, which are critical mediators of both pain processing and central sensitization. In rodent models, experimental hyperhomocysteinemia produces mechanical allodynia (hypersensitivity to touch) that is reversed by T-type calcium channel blockade.[1] Homocysteine enhances trigeminal neuron excitability, lowers the rheobase (threshold for action potential firing), and increases meningeal afferent activity — all consistent with peripheral sensitization.[2] Additionally, homocysteine activates the GluN2A-NMDAR → COX-2 → PGE2 neuroinflammatory pathway, directly promoting proinflammatory prostanoid release from neurons.[3] These are the same NMDA-dependent mechanisms implicated in wind-up and central sensitization in chronic pain states.[4]

Importantly, homocysteine also increases  proinflammatory proteins  (cytokines – IL-1β, IL-6, TNF-α) which leads to oxidative stress — both of which are recognized contributors to central sensitization.[4][5]

   2. Impaired Neurotransmitter Synthesis

MTHFR is essential for producing 5-methyltetrahydrofolate, the methyl donor required for converting homocysteine to methionine, which is then converted to S-adenosylmethionine (SAM). SAM is the principal methyl donor for the synthesis and metabolism of monoamine neurotransmitters — serotonin, dopamine, and norepinephrine — all of which are critical to descending inhibitory pain control.[6][7] Reduced MTHFR activity (particularly 677TT) can impair SAM production, potentially diminishing descending inhibitory pain pathways and contributing to nociplastic/centralized pain.[8][9] This is the same neurotransmitter imbalance implicated in fibromyalgia and central sensitivity syndromes.[10]

A case report demonstrated that a patient with reduced COMT and MTHFR expression treated with leucovorin (folinic acid) 10 mg daily experienced clinically significant reductions in pain scores and improved functionality, suggesting that restoring methylation capacity may have direct analgesic relevance.[11]

   3. MTHFR and Fibromyalgia Syndrome (FMS) / Central Sensitivity Syndromes

The evidence for a direct association between MTHFR C677T and fibromyalgia susceptibility is weak. One study of 200 FMS patients found no significant association between MTHFR C677T and FM overall, though the C677T variant was associated with specific FMS symptoms — stiffness and dry eye.[12] MTHFR is listed among the many polymorphisms identified in FMS genetic studies, but it is not among the primary candidate genes (COMT, SLC6A4, OPRM1 are more consistently implicated).[13][14] A recent systematic review of genetic influences on dynamic experimental pain measures found low-quality evidence for no association between the most-studied pain-related polymorphisms and conditioned pain modulation, and MTHFR was not among the genes with replicated findings.[15]

   4. MTHFR and Migraine-Associated Pain Sensitivity

The strongest clinical pain-related association for MTHFR is with migraine with aura.[16] Within migraine populations, the C677T variant is associated with allodynia (a hallmark of central sensitization), fatigue, photophobia, and increased sensitivity to migraine triggers.[17][18][19] These findings suggest that MTHFR variants may lower the threshold for central sensitization in susceptible individuals, at least in the context of migraine.

   5. Opioid Response and Pain Medication Metabolism

MTHFR does not directly metabolize opioids or analgesic medications — the pharmacokinetic genes most relevant to opioid metabolism are CYP2D6, CYP3A4, and ABCB1.[20][21] However, MTHFR variants may indirectly affect opioid requirements through their influence on dopaminergic reward pathways and pain sensitivity. One study found a high prevalence (87.1%) of MTHFR variants in an opioid use disorder population, hypothesizing that impaired dopamine synthesis from reduced methylation may contribute to altered reward processing.[22]

   References

  1. A Potential Role for T-Type Calcium Channels in Homocysteinemia-Induced Peripheral Neuropathy. Gaifullina AS, Lazniewska J, Gerasimova EV, et al. Pain. 2019;160(12):2798-2810. doi:10.1097/j.pain.0000000000001669.
  2. Implications of High Homocysteine Levels in Migraine Pain: An Experimental Study of the Excitability of Peripheral Meningeal Afferents in Rats With Hyperhomocysteinemia. Ermakova E, Shaidullova K, Gafurov O, et al. Headache. 2024;64(5):533-546. doi:10.1111/head.14710.
  3. Role of GluN2A NMDA Receptor in Homocysteine-Induced Prostaglandin E2 Release From Neurons. Rajagopal S, Fitzgerald AA, Deep SN, Paul S, Poddar R. Journal of Neurochemistry. 2019;150(1):44-55. doi:10.1111/jnc.14775.
  4. Homocysteine and Homocysteine-Related Compounds: An Overview of the Roles in the Pathology of the Cardiovascular and Nervous Systems. Djuric D, Jakovljevic V, Zivkovic V, Srejovic I. Canadian Journal of Physiology and Pharmacology. 2018;96(10):991-1003. doi:10.1139/cjpp-2018-0112.
  5. Uncovering Hyperhomocysteinemia: Global Risk Patterns and Molecular Disruption in Brain and Vascular Health. Ramires Júnior OV, Prauchner GRK, Rieder AS, et al. Journal of Neurochemistry. 2025;169(12):e70327. doi:10.1111/jnc.70327.
  6. Folic Acid, Neurodegenerative and Neuropsychiatric Disease. Kronenberg G, Colla M, Endres M. Current Molecular Medicine. 2009;9(3):315-23. doi:10.2174/156652409787847146.
  7. Folate, Vitamin B12, and Neuropsychiatric Disorders. Bottiglieri T. Nutrition Reviews. 1996;54(12):382-90. doi:10.1111/j.1753-4887.1996.tb03851.x.
  8. The Role of Folate and MTHFR Polymorphisms in the Treatment of Depression. Stengler M. Alternative Therapies in Health and Medicine. 2021;27(2):53-57.
  9. Methylenetetrahydrofolate Reductase and Psychiatric Diseases. Wan L, Li Y, Zhang Z, et al. Translational Psychiatry. 2018;8(1):242. doi:10.1038/s41398-018-0276-6.
  10. Fibromyalgia: Diagnosis and Management. Winslow BT, Vandal C, Dang L. American Family Physician. 2023;107(2):137-144.
  11. Pharmacogenetic Guidance: Individualized Medicine Promotes Enhanced Pain Outcomes. Dragic LL, Wegrzyn EL, Schatman ME, Fudin J. Journal of Pain Research. 2018;11:37-40. doi:10.2147/JPR.S144560.
  12. Angiotensin Converting Enzyme and Methylenetetrahydrofolate Reductase Gene Variations in Fibromyalgia Syndrome. Inanir A, Yigit S, Tekcan A, et al. Gene. 2015;564(2):188-92. doi:10.1016/j.gene.2015.03.051.
  13. Fibromyalgia: A Review of Related Polymorphisms and Clinical Relevance. Janssen LP, Medeiros LF, Souza A, Silva JD. Anais Da Academia Brasileira De Ciencias. 2021;93(suppl 4):e20210618. doi:10.1590/0001-3765202120210618.
  14. Update on the Genetics of the Fibromyalgia Syndrome. Ablin JN, Buskila D. Best Practice & Research. Clinical Rheumatology. 2015;29(1):20-8. doi:10.1016/j.berh.2015.04.018.
  15. The Influence of Genetic and Epigenetic Variations on Dynamic Experimental Pain Measures in Adults With and Without Chronic Musculoskeletal Pain: A Systematic Review. Billens A, De Groote A, Syx D, Meeus M, Van Oosterwijck J. Pain. 2025;:00006396-990000000-00933. doi:10.1097/j.pain.0000000000003608.
  16. Association of the C677T Polymorphism in the MTHFR Gene With Migraine: A Meta-Analysis. Rubino E, Ferrero M, Rainero I, et al. Cephalalgia : An International Journal of Headache. 2009;29(8):818-25. doi:10.1111/j.1468-2982.2007.01400.x.
  17. Investigation of MTHFR C677T Gene Polymorphism, Biochemical and Clinical Parameters in Turkish Migraine Patients: Association With Allodynia and Fatigue. Bahadir A, Eroz R, Dikici S. Cellular and Molecular Neurobiology. 2013;33(8):1055-63. doi:10.1007/s10571-013-9972-1.
  18. Effects of MTHFR Gene Polymorphism on the Clinical and Electrophysiological Characteristics of Migraine. Azimova JE, Sergeev AV, Korobeynikova LA, et al. BMC Neurology. 2013;13:103. doi:10.1186/1471-2377-13-103.
  19. Analysis of the MTHFR C677T Variant With Migraine Phenotypes. Liu A, Menon S, Colson NJ, et al. BMC Research Notes. 2010;3:213. doi:10.1186/1756-0500-3-213.
  20. Review of Opioid Pharmacogenetics and Considerations for Pain Management. Owusu Obeng A, Hamadeh I, Smith M. Pharmacotherapy. 2017;37(9):1105-1121. doi:10.1002/phar.1986.
  21. Pain Polymorphisms and Opioids: An Evidence Based Review. Vieira CMP, Fragoso RM, Pereira D, Medeiros R. Molecular Medicine Reports. 2019;19(3):1423-1434. doi:10.3892/mmr.2018.9792.
  22. A Study of the MTHFR Gene Prevalence in a Rural Tennessee Opioid Use Disorder Treatment Center Population. Cole L, Cernasev A, Webb K, Kumar S, Rowe AS. International Journal of Environmental Research and Public Health. 2022;19(6):3255. doi:10.3390/ijerph19063255.!Pain7246

 

Evidence for  supplementation  for chronic pain in patients with MTHFR variants

The evidence for L-methylfolate, leucovorin, and SAMe as adjunctive therapies for chronic pain in the context of MTHFR variants spans from strong mechanistic rationale to limited but promising clinical data.

L-Methylfolate (5-MTHF)

L-methylfolate is the bioactive form of folate that bypasses the MTHFR enzyme entirely, making it the preferred folate form for patients with reduced MTHFR activity. In vitro studies confirm that cells with low MTHFR activity show no increase in intracellular 5-MTHF after folic acid supplementation, but achieve a 10-fold increase when supplemented directly with 5-MTHF.[1]

   Diabetic peripheral neuropathy (DPN):

  • A narrative review of 7 clinical studies (1 RCT, 5 open-label, 1 retrospective) found that L-methylfolate calcium (LMF), typically combined with methylcobalamin and pyridoxal-5′-phosphate (as the prescription medical food Metanx), provided significant beneficial effects on DPN extending beyond symptomatic relief to modulating underlying pathophysiology.[2]
  • The pivotal Metanx RCT (n=214) used L-methylfolate 3 mg + methylcobalamin 2 mg + pyridoxal-5′-phosphate 35 mg for 24 weeks. While the primary endpoint (vibration perception threshold) was not met, patients receiving active treatment showed clinically significant improvement in neuropathy symptom scores (NTSS-6) at weeks 16 (P=.013) and 24 (P=.033), with improvement inversely related to baseline methylmalonic acid levels.[3]
  • – The MTHFR C677T variant is specifically linked to greater risk of DPN due to its inhibitory effects on folate metabolic pathways.[2]

   Migraine pain

  • An observational study of 135 patients found that patients with the TT genotype showed better therapeutic efficacy with folic acid treatment compared to conventional therapy alone (P<.05), while other genotypes showed no difference between groups.[4]

An important caveat from GeneReviews: while there is a clear biochemical rationale for using L-5-MTHF in MTHFR deficiency, folinic acid (leucovorin) is not a suitable substitute in severe MTHFR deficiency, as it still requires functional MTHFR for conversion to L-5-MTHF.[5]

—

Leucovorin (Folinic Acid)

The evidence for leucovorin specifically in chronic pain is limited to only a single case report. A patient with reduced COMT and MTHFR expression treated with leucovorin 10 mg daily experienced clinically significant reductions in pain scores and improved functionality, demonstrating the potential of pharmacogenetics-guided methylation support in pain management.[6]

However, the metabolic limitation is important: leucovorin is metabolized via 5,10-methylenetetrahydrofolate, which must then be converted to 5-MTHF by MTHFR. In patients with significantly reduced MTHFR activity (e.g., 677TT), this conversion is impaired, making leucovorin theoretically less effective than direct L-methylfolate supplementation.[5][7] For patients with mildly reduced activity (heterozygous CT), leucovorin may still provide adequate substrate.

—

S-Adenosylmethionine (SAMe)

SAMe has the most extensive clinical trial data among these three agents for pain conditions, though none of the trials were specifically designed for MTHFR-variant populations.

   Fibromyalgia: Two double-blind, placebo-controlled trials provide direct evidence:

  • Jacobsen et al. (n=44): Oral SAMe 800 mg/day for 6 weeks improved clinical disease activity (P=.04), pain during the last week (P=.002), fatigue (P=.02), morning stiffness (P=.03), and mood (P=.006) compared to placebo.[8]
  • Tavoni et al. (n=17, crossover): SAMe significantly reduced the number of trigger points (P<.02) and improved depression scores compared to placebo.[9]

   Osteoarthritis:

  • A meta-analysis of 11 RCTs found SAMe was comparable to NSAIDs in reducing pain (ES=0.12, 95% CI −0.029 to 0.273) and functional limitation (ES=0.025), with fewer adverse effects.[10] A large multicenter trial (n=734) confirmed SAMe 1200 mg/day had equivalent analgesic activity to naproxen 750 mg/day, with significantly better tolerability.[11] A Cochrane review, however, noted that the overall evidence quality was limited and did not allow firm claims about effectiveness.[12]

   Neuropathic pain (preclinical):

In a mouse spared nerve injury model, chronic oral SAMe (20 mg/kg, 3×/week for 4 months) reduced mechanical hypersensitivity and completely blocked nerve injury-induced cognitive impairment. This was associated with reversal of chronic pain-induced DNA hypomethylation in the frontal cortex, with SAMe reversing approximately one-third of the differentially methylated genomic regions caused by nerve injury — including pain-related genes such as Scn10a, Trpa1, Ntrk1, and Gfap.[13][14]

Mechanism: SAMe’s analgesic effects appear to operate through multiple pathways — enhancing monoamine neurotransmitter synthesis (serotonin, norepinephrine) via methylation reactions, direct anti-inflammatory effects, epigenetic modulation of pain-related gene expression, and potentially COX-2 inhibition.[15][16][17] Its antidepressant-like effects are dependent on serotonin synthesis and 5-HT₁A receptor activation.[17]

—

Safety Considerations

Agent

Typical Dose

Key Safety Concerns

References

L-methylfolate

3–15 mg/day (pain);

up to 40 mg/day

(severe MTHFR deficiency)

Minimal adverse effects; well tolerated

[1], [2], [3]

Leucovorin

10 mg/day (case report dose)

Generally well tolerated; not FDA-approved for pain

[4]

SAMe

800–1200 mg/day in divided doses

Risk of mania/hypomania in bipolar patients; mild GI effects (nausea); theoretical serotonin syndrome risk with serotonergic drugs; take on empty stomach

[5], [6], [7]

SAMe carries the most notable safety concern: it has been reported to induce mania in patients with bipolar disorder (9 of 11 bipolar patients in one open study experienced mood elevation).[15] It should be used cautiously with serotonergic medications given its effects on serotonin synthesis.[18]

—

Clinical Synthesis for Patients with Elevated Homocysteine Levels

The mechanistic rationale for methylation support in chronic pain is coherent: MTHFR variants → reduced 5-MTHF → impaired SAM production → decreased monoamine neurotransmitter synthesis and epigenetic dysregulation → enhanced pain sensitivity. However, the clinical evidence remains preliminary, with small trials and no large RCTs specifically testing these agents in MTHFR-variant pain populations.

   A reasonable evidence-informed approach would be:

1. First: Correct B12 deficiency (already planned) and recheck homocysteine

2. If homocysteine remains elevated: Consider MTHFR genotyping; if 677TT or compound heterozygous, L-methylfolate (preferred over leucovorin or folic acid) at 3–15 mg/day with riboflavin

3. If chronic pain persists: SAMe 800–1200 mg/day could be considered as adjunctive therapy, with the strongest evidence in fibromyalgia and osteoarthritis contexts

   References

  1. Folate Insufficiency Due to MTHFR Deficiency Is Bypassed by 5-Methyltetrahydrofolate. Vidmar Golja M, Šmid A, Karas Kuželički N, et al. Journal of Clinical Medicine. 2020;9(9):E2836. doi:10.3390/jcm9092836.
  2. L-Methylfolate in Diabetic Peripheral Neuropathy: A Narrative Review. Christofides EA, Valentine V. Endocrine Practice : Official Journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists. 2023;29(8):663-669. doi:10.1016/j.eprac.2023.04.005.
  3. Metanx in Type 2 Diabetes With Peripheral Neuropathy: A Randomized Trial. Fonseca VA, Lavery LA, Thethi TK, et al. The American Journal of Medicine. 2013;126(2):141-9. doi:10.1016/j.amjmed.2012.06.022.
  4. Polymorphism’s Influence on the Clinical Features and Therapeutic Effects in Patients With Migraine: An Observational Study. Guo J, Hao X, Wang R, et al. Frontiers in Neurology. 2022;13:1074857. doi:10.3389/fneur.2022.1074857.
  5. Homocystinuria due to Deficiency of N(5,10)-Methylenetetrahydrofolate Reductase Activity. Umair M, Alfadhel M. GeneReviews® [Internet]. Updated 2025 Dec 4.
  6. Pharmacogenetic Guidance: Individualized Medicine Promotes Enhanced Pain Outcomes. Dragic LL, Wegrzyn EL, Schatman ME, Fudin J. Journal of Pain Research. 2018;11:37-40. doi:10.2147/JPR.S144560.
  7. Leucovorin Calcium. Food and Drug Administration. Updated date: 2022-03-03.
  8. Oral S-Adenosylmethionine in Primary Fibromyalgia. Double-Blind Clinical Evaluation. Jacobsen S, Danneskiold-Samsøe B, Andersen RB. Scandinavian Journal of Rheumatology. 1991;20(4):294-302. doi:10.3109/03009749109096803.
  9. Evaluation of S-Adenosylmethionine in Primary Fibromyalgia. A Double-Blind Crossover Study. Tavoni A, Vitali C, Bombardieri S, Pasero G. The American Journal of Medicine. 1987;83(5A):107-10. doi:10.1016/0002-9343(87)90862-x.
  10. Safety and Efficacy of S-Adenosylmethionine (SAMe) for Osteoarthritis. Soeken KL, Lee WL, Bausell RB, Agelli M, Berman BM. The Journal of Family Practice. 2002;51(5):425-30.
  11. Italian Double-Blind Multicenter Study Comparing S-Adenosylmethionine, Naproxen, and Placebo in the Treatment of Degenerative Joint Disease. Caruso I, Pietrogrande V. The American Journal of Medicine. 1987;83(5A):66-71. doi:10.1016/0002-9343(87)90854-0.
  12. S-Adenosylmethionine for Osteoarthritis of the Knee or Hip. Rutjes AW, Nüesch E, Reichenbach S, Jüni P. The Cochrane Database of Systematic Reviews. 2009;(4):CD007321. doi:10.1002/14651858.CD007321.pub2.
  13. Therapeutic Benefits of the Methyl Donor S-Adenosylmethionine on Nerve Injury-Induced Mechanical Hypersensitivity and Cognitive Impairment in Mice. Grégoire S, Millecamps M, Naso L, et al. Pain. 2017;158(5):802-810. doi:10.1097/j.pain.0000000000000811.
  14. The Methyl Donor S-Adenosyl Methionine Reverses the DNA Methylation Signature of Chronic Neuropathic Pain in Mouse Frontal Cortex. Topham L, Gregoire S, Kang H, et al. Pain Reports. 2021 Jul-Aug;6(2):e944. doi:10.1097/PR9.0000000000000944.
  15. S-Adenosyl Methionine (SAMe) for Depression in Adults. Galizia I, Oldani L, Macritchie K, et al. The Cochrane Database of Systematic Reviews. 2016;10:CD011286. doi:10.1002/14651858.CD011286.pub2.
  16. Ademetionine (S-Adenosylmethionine) Neuropharmacology: Implications for Drug Therapies in Psychiatric and Neurological Disorders. Bottiglieri T. Expert Opinion on Investigational Drugs. 1997;6(4):417-26. doi:10.1517/13543784.6.4.417.
  17. S-Adenosyl-L-Methionine Antidepressant-Like Effects Involve Activation of 5-Ht Receptors. Sales AJ, Maciel IS, Crestani CC, Guimarães FS, Joca SR. Neurochemistry International. 2023;162:105442. doi:10.1016/j.neuint.2022.105442.
  18. Efficacy of the Dietary Supplement S-Adenosyl-L-Methionine. Fetrow CW, Avila JR. The Annals of Pharmacotherapy. 2001;35(11):1414-25. doi:10.1345/aph.1Z443.
  19. Role of S-Adenosyl-L-Methionine in the Treatment of Depression: A Review of the Evidence. Mischoulon D, Fava M. The American Journal of Clinical Nutrition. 2002;76(5):1158S-61S. doi:10.1093/ajcn/76/5.1158S.

 

 

 

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Evidence for MTHFR and Chronic Pain Conditions:

The most relevant data comes from studies of fibromyalgia and neuropathic pain. In fibromyalgia, MTHFR is among 30 genes identified as potentially associated with the condition, though the evidence is mixed.[2] A Turkish study of 200 fibromyalgia patients found no significant association between MTHFR C677T polymorphism and fibromyalgia susceptibility overall (OR: 1.20, 95% CI: 0.82-1.78, p>0.05), but did find associations with specific symptoms including stiffness and dry eye.[3]

For neuropathic pain, one study found MTHFR C677T polymorphism conferred risk for diabetic peripheral neuropathy in Iranian patients with type 2 diabetes.[4] In migraine, the MTHFR C677T genotype was significantly associated with migraine susceptibility and with specific symptoms including allodynia and fatigue.[5]

However, a comprehensive 2016 review of genetic predictors of chronic pain conditions noted that while numerous genetic variants have been implicated, “the genetic landscape of common chronic pain conditions suggests minor contributions from a large number of single nucleotide polymorphisms representing different functional pathways.” MTHFR was not highlighted as a major contributor to pain chronification.[6]

Lack of Evidence for Acute-to-Chronic Pain Transition:

Critically, no studies have specifically examined whether MTHFR polymorphisms predict the transition from acute to chronic pain. The existing literature focuses on associations with established chronic pain syndromes rather than prospective studies of pain chronification. The ACMG guideline notes that while modest positive associations have been found between MTHFR polymorphisms and various conditions including migraine, “many other studies looking at similar complications found no statistical association.”[1]

Prevalence of Major MTHFR Variants:

The two most common MTHFR polymorphisms show marked geographic and ethnic variation::

  MTHFR C677T (rs1801133):

  • European populations: 10-16% homozygous (TT), with >25% of Hispanics and 10-15% of North American Caucasians being TT homozygotes[7][1]
  • Chinese Han population: Overall 677T allele frequency 45.2%, with 23.2% TT homozygotes, showing a north-to-south gradient (highest 40.8% TT in northern Shandong, lowest 6.4% TT in southern Hainan)[8]
  • Mexican populations: Highest worldwide frequencies, with enrichment in southern regions; 677T allele derived primarily from Amerindian ancestry[9][10]
  • West African populations: Lowest worldwide frequencies of the 677T allele[9]
  • Greek population: 28.2% TT homozygotes, 52.7% CT heterozygotes, 19.1% CC normal; overall T allele frequency 54.6%[11]

MTHFR A1298C (rs1801131):

  • European populations: 4-6% homozygous (CC)[7]
  • Chinese Han population: Overall 1298C allele frequency 18.6%, with 3.9% CC homozygotes, showing a south-to-north gradient (opposite to C677T)[8]
  • Mexican populations: Among the lowest worldwide frequencies, with 1298C representing European genetic contribution[10]
  • Greek population: 3.9% CC homozygotes, 27.4% AC heterozygotes, 68.7% AA normal; overall C allele frequency 17.6%[11]

The two variants are in linkage disequilibrium, meaning compound heterozygotes (one copy of each variant) are typically in trans configuration.[1]

Clinical Bottom Line:

MTHFR polymorphism testing is not recommended for chronic pain evaluation. The ACMG guideline explicitly states there is “lack of evidence for MTHFR polymorphism testing” for most clinical indications.[1] While these variants affect homocysteine metabolism and folate status, their clinical significance for pain conditions remains uncertain. The high prevalence of these polymorphisms in healthy populations (up to 40% TT homozygotes in some regions) further argues against their utility as predictive markers for pain chronification.

References

  1. Folate Insufficiency Due to MTHFR Deficiency Is Bypassed by 5-Methyltetrahydrofolate. Vidmar Golja M, Šmid A, Karas Kuželički N, et al. Journal of Clinical Medicine. 2020;9(9):E2836. doi:10.3390/jcm9092836.
  2. Comparative Analysis of Treatment With Folate Forms in Clinical Practice. Skavinska O, Rossokha Z, Stefanyshyn V, et al. Nutrition Reviews. 2025;:nuaf216. doi:10.1093/nutrit/nuaf216.
  3. Folate Supplementation in Fertility and Pregnancy: The Advantages of (6s)5-Methyltetrahydrofolate. Miraglia N, Dehay E. Alternative Therapies in Health and Medicine. 2022;28(4):12-17.
  4. Treatment of Vitamin B12 Deficiency-Methylcobalamine? Cyancobalamine? Hydroxocobalamin?-Clearing the Confusion. Thakkar K, Billa G. European Journal of Clinical Nutrition. 2015;69(1):1-2. doi:10.1038/ejcn.2014.165.
  5. Gene Identification for the cblD Defect of Vitamin B12 Metabolism. Coelho D, Suormala T, Stucki M, et al. The New England Journal of Medicine. 2008;358(14):1454-64. doi:10.1056/NEJMoa072200.

 

References – MTHFR Genetic Variants and Chronic Pain

  1. ACMG Practice Guideline: Lack of Evidence for MTHFR Polymorphism Testing. Hickey SE, Curry CJ, Toriello HV. Genetics in Medicine : Official Journal of the American College of Medical Genetics. 2013;15(2):153-6. doi:10.1038/gim.2012.165.
  2. Fibromyalgia: A Review of Related Polymorphisms and Clinical Relevance. Janssen LP, Medeiros LF, Souza A, Silva JD. Anais Da Academia Brasileira De Ciencias. 2021;93(suppl 4):e20210618. doi:10.1590/0001-3765202120210618.
  3. Angiotensin Converting Enzyme and Methylenetetrahydrofolate Reductase Gene Variations in Fibromyalgia Syndrome. Inanir A, Yigit S, Tekcan A, et al. Gene. 2015;564(2):188-92. doi:10.1016/j.gene.2015.03.051.
  4. Association Between MTHFR Variant and Diabetic Neuropathy. Kakavand Hamidi A, Radfar M, Amoli MM. Pharmacological Reports : PR. 2018;70(1):1-5. doi:10.1016/j.pharep.2017.04.017.
  5. Investigation of MTHFR C677T Gene Polymorphism, Biochemical and Clinical Parameters in Turkish Migraine Patients: Association With Allodynia and Fatigue. Bahadir A, Eroz R, Dikici S. Cellular and Molecular Neurobiology. 2013;33(8):1055-63. doi:10.1007/s10571-013-9972-1.
  6. Genetic Predictors of Human Chronic Pain Conditions. Zorina-Lichtenwalter K, Meloto CB, Khoury S, Diatchenko L. Neuroscience. 2016;338:36-62. doi:10.1016/j.neuroscience.2016.04.041.
  7. ACOG Practice Bulletin No. 197: Inherited Thrombophilias in Pregnancy. American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins–Obstetrics. Obstetrics and Gynecology. 2018;132(1):e18-e34. doi:10.1097/AOG.0000000000002703.
  8. Geographical Distribution of MTHFR C677T, A1298C and MTRR A66G Gene Polymorphisms in China: Findings From 15357 Adults of Han Nationality. Yang B, Liu Y, Li Y, et al. PloS One. 2013;8(3):e57917. doi:10.1371/journal.pone.0057917.
  9. Prevalence of Methylenetetrahydrofolate Reductase 677T and 1298C Alleles and Folate Status: A Comparative Study in Mexican, West African, and European Populations. Guéant-Rodriguez RM, Guéant JL, Debard R, et al. The American Journal of Clinical Nutrition. 2006;83(3):701-7. doi:10.1093/ajcn.83.3.701.
  10. Heterogenous Distribution of MTHFR Gene Variants Among Mestizos and Diverse Amerindian Groups From Mexico. Contreras-Cubas C, Sánchez-Hernández BE, García-Ortiz H, et al. PloS One. 2016;11(9):e0163248. doi:10.1371/journal.pone.0163248.
  11. Association of Methylene Tetrahydrofolate Reductase (MTHFR) Gene Polymorphisms With Serum Folate, Cobalanin and Homocysteine Concentrations in Greek Adults. Mazokopakis EE, Papadomanolaki MG, Papadakis JA. Scandinavian Journal of Clinical and Laboratory Investigation. 2023;83(2):69-73. doi:10.1080/00365513.2023.2167232.

Emphasis on Education

 

Accurate Clinic promotes patient education as the foundation of it’s medical care. In Dr. Ehlenberger’s integrative approach to patient care, including conventional and complementary and alternative medical (CAM) treatments, he may encourage or provide advice about the use of supplements. However, the specifics of choice of supplement, dosing and duration of treatment should be individualized through discussion with Dr. Ehlenberger. The following information and reference articles are presented to provide the reader with some of the latest research to facilitate evidence-based, informed decisions regarding the use of conventional as well as CAM treatments.

 

For medical-legal reasons, access to these links is limited to patients enrolled in an Accurate Clinic medical program.

 

Should you wish more information regarding any of the subjects listed – or not listed –  here, please contact Dr. Ehlenberger. He has literally thousands of published articles to share on hundreds of topics associated with pain management, weight loss, nutrition, addiction recovery and emergency medicine. It would take years for you to read them, as it did him.

 

For more information, please contact Accurate Clinic.

 

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