How BHMT Gene Variation Affects Methylation and Health

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.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on methylation & mthfr. Browse all Methylation & MTHFR education

BHMT is one of the quieter genes in the methylation story, but it does important work. It provides a backup route for recycling homocysteine — a step that keeps this amino acid from building up and helps regenerate the methyl groups your cells use for hundreds of reactions. Understanding how BHMT variation fits into your methylation pathways offers useful, pathway-level context about your biology.

What the BHMT gene does

BHMT stands for betaine-homocysteine methyltransferase. The enzyme it encodes converts homocysteine back into methionine using betaine (trimethylglycine) as the methyl donor. Methionine is then used to make S-adenosylmethionine (SAMe), the universal methyl donor for DNA, neurotransmitters, and many other targets. BHMT is most active in the liver and kidneys, where it handles a large share of homocysteine recycling.

How BHMT works alongside MTHFR and the methionine cycle

There are two routes for turning homocysteine back into methionine. One depends on folate and the enzyme made by MTHFR, using vitamin B12 as a cofactor. The other is the BHMT route, which uses betaine instead of folate. Having a betaine-powered backup matters: if the folate pathway is running slowly — for example, in someone with a reduced-activity MTHFR variant — the BHMT route can help pick up the slack. The two systems together keep homocysteine in a healthy range.

Common BHMT variants

The most studied BHMT variant is rs3733890, sometimes written as R239Q, which changes a single amino acid in the enzyme. Research has examined how this and nearby variants relate to homocysteine levels, betaine metabolism, and choline requirements, though findings vary across populations. Like most methylation genes, BHMT variants are common and are best understood as tuning knobs on a pathway rather than switches that determine health outcomes.

Why homocysteine balance matters

Homocysteine is a normal metabolic intermediate, but chronically elevated levels have been studied as a marker associated with cardiovascular and cognitive health. The body manages homocysteine through the folate-dependent, BHMT-dependent, and transsulfuration (CBS) pathways working together. Genes across these routes — MTHFR, BHMT, MTR, and CBS — collectively shape how efficiently you keep homocysteine in balance. This is education about your pathways, not a diagnosis or a treatment plan.

Nutrients that support the BHMT pathway

The BHMT route runs on betaine and its precursor choline. Choline-rich foods include eggs, liver, and to a lesser degree legumes and cruciferous vegetables; betaine is found in beets, spinach, and whole grains. Because these nutrients feed the methyl economy, dietary intake interacts with your BHMT genotype. Genetics is a guide, not a guarantee — variants suggest tendencies, but nutrition, B-vitamin status, and lifestyle shape how the pathway actually performs. Any supplement decision, especially involving choline, betaine, or B vitamins, should be made with a qualified healthcare provider.

What your PlexusDx results reveal about methylation

The PlexusDx Precision Peptide Genetic Test explores 14 pathways, 49 peptides, 150+ genetic insights, including variants across the methylation pathways that BHMT and MTHFR help run. It offers pathway-level education about how your genes influence methyl-group metabolism — it does not diagnose a methylation disorder, measure your homocysteine, or tell you what to put in your body. For actual homocysteine or B-vitamin levels, a blood test ordered by a provider is the right tool.

Frequently Asked Questions About the BHMT Gene

What does the BHMT gene do?

BHMT encodes betaine-homocysteine methyltransferase, an enzyme that recycles homocysteine back into methionine using betaine as the methyl donor. It acts mainly in the liver and kidneys and provides a folate-independent backup to the MTHFR pathway, helping keep homocysteine balanced and regenerating methyl groups your cells rely on.

Is a BHMT variant something to worry about?

Usually not on its own. BHMT variants like rs3733890 are common and act as tuning knobs on the methylation pathway, not disease switches. They are best interpreted alongside other methylation genes, diet, and B-vitamin status. Genetics is a guide, not a guarantee, and a variant does not determine any health outcome.

How does BHMT relate to MTHFR?

Both help convert homocysteine back into methionine, but by different routes. MTHFR uses the folate pathway with vitamin B12, while BHMT uses betaine. Having two routes provides redundancy: if one runs slowly, the other can help maintain homocysteine balance. This is why methylation is best viewed as a network, not a single gene.

Does the Precision Peptide Genetic Test measure homocysteine?

No. The test analyzes genetic variants across methylation and related pathways for educational purposes. It does not measure homocysteine, diagnose a methylation disorder, or prescribe nutrients. To measure actual homocysteine or B-vitamin levels, use a blood test ordered by a qualified healthcare provider who can interpret the results in context.

Want to understand the genetic variants behind your methylation pathways? Take the Precision Peptide Genetic Test.

This article is part of the PlexusDx Education Hub. Browse all Methylation & MTHFR education

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

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.