---
title: Methylated Folate for Normal Homocysteine Status
description: Methylated folate (5-MTHF) may support normal homocysteine metabolism in people with MTHFR polymorphisms that limit folate conversion.
image: https://www.casi.org/hubfs/casi/featured/adobestock_501148389.jpeg
---

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# Methylated Folate for Normal Homocysteine Status

DM Danielle C. Male, MS, CNS, LDN Apr 20, 2023

![Methylated Folate for Normal Homocysteine Status](https://www.casi.org/hs-fs/hubfs/casi/featured/adobestock_501148389.jpeg?width=960)

[Methylation](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/) in the human body is a chemical reaction that transfers a [one-carbon unit](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/) from one compound to another. Although that sounds relatively simple, methylation is critical for human functioning and influences [gene expression, antioxidant status, and protein synthesis](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). Without proper methylation, human health can be disrupted. 

One of the most common causes of dysregulated methylation is hereditary genetic polymorphisms (or variations) involving the [methylenetetrahydrofolate reductase (MTHFR) enzyme](https://pubmed.ncbi.nlm.nih.gov/25449138/). MTHFR regulates methylation and converts [folate (vitamin B9) into its bioactive form](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/). [Folate](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) is a vitamin essential for DNA synthesis, amino acid status, and normal cell growth and division. Genetic MTHFR polymorphisms may [reduce](https://pubmed.ncbi.nlm.nih.gov/25449138/) the MTHFR enzyme activity.

Under normal circumstances, folate from food or supplements is converted into [5,10-methylenetetrahydrofolate (5,10-MTHF)](https://pubmed.ncbi.nlm.nih.gov/25449138/). Then, with the help of the [MTHFR enzyme](https://pubmed.ncbi.nlm.nih.gov/25449138/), 5,10-MTHF is converted into [5-methyltetrahydrofolate (5-MTHF)](https://pubmed.ncbi.nlm.nih.gov/25449138/), which is the [main folate metabolite](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) in the blood. This pathway is called the [transmethylation pathway](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). 

Healthy production of 5-MTHF allows homocysteine to properly convert into [methionine](https://pubmed.ncbi.nlm.nih.gov/25449138/), a critical amino acid for proper [neurotransmitter, protein, and DNA status.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) In the presence of MTHFR polymorphism(s), homocysteine may only remain homocysteine in the body (and will not be converted into methionine). [Elevated homocysteine](https://pubmed.ncbi.nlm.nih.gov/25449138/) is associated with [cellular dysfunction](https://pubmed.ncbi.nlm.nih.gov/25449138/) and [unhealthy inflammatory responses](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/), and may also be associated with [bone disorders](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425139/), [neurodegenerative diseases](https://onlinelibrary.wiley.com/doi/full/10.1111/bcpt.12424), and [dysregulated blood sugar](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). Elevated homocysteine may also be a [risk factor](https://pubmed.ncbi.nlm.nih.gov/25449138/) for [cardiac dysfunction](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). 

A common MTHFR polymorphism is [C677T](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/), and it is associated with a [50% reduction in MTHFR enzyme activity](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). Another common polymorphism is [A1298C](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/). Both C677T and A1298C polymorphisms are associated with [elevated homocysteine](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703276/).

Maintaining a healthy 5-MTHF status in the presence of MTHFR polymorphism(s) may be difficult. After all, the conversion of folate to 5-MTHF may be reduced. Supplementing directly with [methylated folate](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) as 5-MTHF may [bypass](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) this difficulty and promote healthy bioactive folate status in those with MTHFR polymorphisms. 

A [systematic review](https://pubmed.ncbi.nlm.nih.gov/30010385/) found that participants administered 5-MTHF supplementation had effectively increased their folate status compared to those administered folic acid (a synthetic form of folate). [Researchers in vitro](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) administered folic acid supplementation to cells with low MTHFR enzyme activity. Within these cells, there was [no increase](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) in 5-MTHF status. On the contrary, cells with low MTHFR enzyme activity supplemented directly with 5-MTHF resulted in a [10-fold](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) increase in intracellular levels of 5-MTHF. 

These results suggest that 5-MTHF supplementation may be [clinically beneficial to individuals with identified or unknown MTHFR polymorphism(s)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/). Furthermore, [certain medications](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564482/) may also reduce MTHFR enzyme activity. 

Proper folate status is vital in supporting normal homocysteine metabolism. However, methylated folate (as 5-MTHF) may further promote normal homocysteine metabolism in certain individuals. It is important to acknowledge that other B vitamins, such as [vitamins B2, B6, and B12](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425139/), also support healthy homocysteine metabolism and should be consumed in tandem with folate.

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DM

### Danielle C. Male, MS, CNS, LDN

Clinical Application

## Clinical Considerations in Practice

 In clinical practice, practitioners considering the topics discussed above may also weigh nutrient form, delivery and formulation, alongside individual patient variability.

### Practitioner Formulation Example

![L-5-MTHF 1,700 mcg DFE (1 mg)](https://cdn.sanity.io/images/lemtscrs/production-www/341667731c8282293652729e44b6380b614ec874-2000x2000.png?w=128&h=128&fit=max&auto=format)

L-5-MTHF 1,700 mcg DFE (1 mg)

Methylated folate · Capsules

[Explore Formulations →](https://www.designsforhealth.com/products/l-5-mthf-1000mcg)

## Continue your research

#### [Research & Education B Vitamins 101: Functions, Food Sources, and Daily Requirements Jun 25, 2026](https://www.casi.org/articles/b-vitamins-101-functions-food-sources-and-daily-requirements)

#### [Research & Education Magnesium Supplementation 101: Choosing the Best Form for Your Patient’s Needs Jun 02, 2026](https://www.casi.org/articles/magnesium-supplementation-101-choosing-the-best-form-for-your-patients-needs)

#### [Research & Education Magnesium Glycinate Chelate Buffered: A Smart Approach to Magnesium Supplementation May 21, 2026](https://www.casi.org/articles/magnesium-glycinate-chelate-buffered-a-smart-approach-to-magnesium-supplementation)

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