How to Choose the Right Folate or Folic Acid Supplement
Vitamin B9 (also known as folate or folic acid) is available in various types of nutritional supplements - and each has its pros and cons. Here you will learn how these supplements are different, so you can choose the one that best fits your needs.
Folate and Folic Acid – an Introduction
Folate is a water soluble vitamin, also known as vitamin B9. This vitamin is vital for DNA and RNA production, cell division and production of different amino acids in the body.
The word folate is used as an umbrella term that includes different molecular forms of folate found in food as well as those created synthetically in laboratories.
Folic acid is the synthetic form of folate, which is most commonly included into nutritional supplements and multivitamins.
There are quite a few important differences between the various forms of folate and folic acid. They have different absorption rates and once they enter the body, they are metabolized differently.
It is important to know these differences, so you are able to choose the folate/folic acid supplement that best suits your needs. We’ll take a closer look at these supplements and explain the differences in more detail.
In this article, you will find:
Different Types of Folate and Folic Acid Supplements – an Overview
We can divide the available folate and folic acid supplements into 4 major categories.
1. Food Based Folate Supplements
Food based folate supplements contain folate derived from raw foods. The source of folate in these supplements can be any vegetable, rich in naturally occurring folate (broccoli seems to be a popular choice).
It is rare to get food based folate as a standalone formula. Typically, this type of folate is combined with other vitamins and minerals. It is an important part of whole food based multivitamins, prenatals and B complex vitamins.
Food sourced folate supplements are ideal for those people who want to avoid taking any synthetically made vitamins and are planning to take folate as part of food based multivitamin supplement.
Popular choices for food based multivitamins include:
Mary Ruth's Organic Multivitamin (Liquid multivitamin made with certified organic ingredients.)
There is one potential problem with food sourced type of folate, though. This type of folate is notoriously susceptible to oxidation and quickly looses potency during manufacturing and storage. It is generally though that other forms (such as methylfolate or folinic acid) are more reliable in raising blood levels of folate. So, if you need to take folate for a specific health condition (not just as a way of supporting general wellbeing), it is better to choose another form of folate supplement (methylfolate of folinic acid).
2. Folic Acid Supplements
Folic acid is the form of folate that is most commonly included into multivitamins, B complex vitamins or prenatals. There are 2 main reasons for this widespread use: the instability of natural folates and low costs of production of folic acid.
Folic acid seems to be the obvious choice for people who like the ease and convenience of taking multiple vitamins in 1 daily pill - since most multivitamins on the market contain folate in the from of folic acid.
However, other forms of folate have several important benefits over folic acid. If you take the time, you can also find a vitamin pack that contains methylfolate and not folic acid.
Also, there are some groups of people who should always steer clear of folic acid supplements and take another form of folate. These include people with certain medical conditions, genetic mutations, those who are taking specific medications and others.
You can find more details on issues related to folic acid below.
Problems with Folic Acid Supplements
Folic acid is a synthetic molecule that can’t be used directly by the body. Once you take your folic acid supplement, it must first be converted into the form of folate that is circulating in the body, called tetrahydrofolate.
In order to make this conversion, our body uses the enzyme called methylenetetrahydrofolate (MTHFR). It has been shown that a large part of population has impaired activity of this enzyme – there are estimates that between 40 and 60% of people have some degree of MTHFR gene mutation.
If you have this mutation, folic acid that you take doesn't convert well into the biologically active folate. As a result, you may have chronically low levels of folate in your blood – even if you constantly take folic acid supplements.
At the same time, impaired conversion process leaves you with unmetabolized folic acid circulating in your bloodstream. This may potentially lead to a range of adverse health effects.
Taking too large doses of folic acid can also cause problems – even if you don’t have the MTHFR gene mutation. Your body simply isn’t able to utilize all the folic acid that you ingest and some of it remains unmetabolized.
To minimize the risk of long term side effects of overdosing on folic acid, scientists have established the upper intake limit. For adults, this is set at 1.000 mcg of folic acid daily.
3. Methylfolate Supplements
Methylfolate is the most bioavailable form of folate, which means that your body can use it without any conversion. It is a stable, water-soluble folate with long shelf life.
Methylfolate is more expensive to make than folic acid and for that reason it is still not widely used in nutritional supplements. However, as health issues with folic acid are becoming more and more known, methylfolate is steadily gaining popularity.
Methylfolate supplement is the folate supplement that is best suited for a large majority of people.
However, there are some people who should always choose methyfolate over other folate supplements. These include:
- Those who have a diagnosed MTHFR mutation or have a close family relation with this mutation
For this group of people it is absolutely necessary that they get their folate in methylfolate form – they are simply unable to convert folic acid well. Folinic acid is also a possible choice, but not as good as methylfolate (it still needs conversion; however, it is not affected by the MTHFR enzyme)
- Pregnant Women
Many pregnant women are aware of the benefits of folate for the developing baby.
Folate is necessary for the development of new cells and needed for the normal closure of the neural fold.
The number 1 form of folate in prenatal supplements is folic acid. However, if you are pregnant or planning to get pregnant, it is always best to get your folate in the form of methylfolate and not folic acid. The main reason for this is that you may have a mild MTHFR defect that has never been diagnosed. In this case, you are able to convert folic acid to bioactive folate to a certain degree – however, your blood levels of folate may be too low to support healthy pregnancy. Unlike folic acid, methylfolate will reliably raise your blood folate levels.
There are also other benefits of taking methylfolate during pregnancy. Many women find that folic acid causes stomach pain and nausea, while methylfolate seems to be easier to digest. It has also been shown that women who take methylfolate supplement have lower risk of pregnancy anemia than women who take folic acid supplements (1, 2).
- People with B12 deficiency or with higher risk for this deficiency
Folic acid masks the blood signs of B12 deficiency (anemia), which allows the condition to progress and cause irreparable neurological damage. If you’ve been diagnosed with B12 deficiency and need to monitor your condition or you have a close family member with B12 deficiency, you need to take methylfolate supplements and not supplements containing folic acid.
- If you are planning to take folate for brain health, depression or anxiety
Methylfolate is the form of folate that crosses the blood brain barrier and directly enters the brain cells. Once it gets there, it helps with the production of important neurotransmitters (chemical messengers in the brain).
Methylfolate is commonly used for enhancing cognitive function. People with depression take it as a standalone nutritional supplement or together with their anti-depressant medication (it has been shown to enhance the effects of SSSRIs in those people who respond poorly to antidepressants).
Methylfolate is also taken for alleviating the symptoms of anxiety and for mood disorders.
- Older people
As we age, our ability to convert folic acid into the bioactive form of folate decreases (even if we don’t have MTHFR mutation). This leads to associated issues – unmetabolized folic acid in serum and low blood folate levels. That is why older people are recommended to take the bioavailable methylfolate and not folic acid supplements.
- If you take medication that interfere with folic acid metabolism
Some prescription drugs disrupt how folic acid is metabolized in the body. These include:
- Oral contraceptives
- Metformin (medication for blood sugar control, commonly used by diabetics and PCOS patients)
- Anticonvulsants ( valproate, primidone, phenytoin, etc)
- Methotrexate (anticancer medication, also used for rheumatoid arthristis, Chron’s disease, psoriasis)
- Sulfasalazine (used by people with Chron’s, ulcerative colitis and rheumatoid arthritis)
- Certain diuretics (water pills, such as triamterene)
If you take any of these medications, your body won’t be efficient at converting the folic acid that you ingest. That is why it is recommended that you take other, more bioavailable forms of folate supplement, such as methylfolate or folinic acid.
4. Folinic Acid Supplements
Folinic acid is a form of folate that can be found in natural sources. It is more bioavailable than folic acid as it needs a couple of steps less in the conversion process. A major plus of folinic acid is that its metabolism is not affected by the MTHFR gene mutation. Folinic acid is less bioavailable than methylfolate, though.
Folinic acid is the rarest form of folate supplementation. It is typically used by people with specific health conditions.
Folinic acid is taken in the following cases:
- Alongside chemotherapy medication fluoroucacil
Folinic acid enhances the action of fluoroucacil on cancer cells.
- Folinic acid for reducing methotrexate toxicity
Folinic acid is also used by people who take medication methotrexate to alleviate its toxic side effects. This medication is commonly used by people with arthritis and psoriasis.
- Autism spectrum disorder, cerebral folate deficiency and folate receptor antibodies
Folinic acid is also prescribed for some people with autism disorder and conditions related to cerebral folate deficiency and folate receptor antibodies.
- People with anxiety and mood disorders
Sometimes people use folinic acid for relieving the symptoms of anxiety and mood disorders; however, methylfolate seems to have more evidence of use for these conditions.
Folic Acid Supplements
There is a wide range of folic acid supplements that you can choose from. All of these supplements are surprisingly similar, though. They all contain the same molecular form of folate – namely folic acid – and they all have the same added ingredients that make up the tablet (such as binders and fillers).
However, there are a couple of small differences between them. Main things that are different are:
The typical supplemental dose for folic acid is 400mcg, so that explain why so many tablets come in this dosage. You can also find tablets with 800 mcg of folic acid, which are a popular choice among pregnant women.
There are also supplements that contain higher dosages of folic acid. These are created for people who have a diagnosed medical condition that requires high dosages of supplemental folic acid.
These conditions include high homocysteine levels, methotextrate therapy (for example for psoriasis or arthritis) or pregnancy with a high risk of neural defect. Women who have previously had pregnancy with neural defect take up to 5 mg of folic acid daily.
If you don’t fall into the above mentioned categories, though, be careful not to exceed the upper intake limit for folic acid. This is set at 1.000 mcg per day. It is not recommended that you take too much folic acid as this increases the risk of side effects.
Sources of Folic Acid
Most of the folic supplements contain folic acid that is 100% synthetically made. Few of them, however, contain folic acid derived from fruits. The chemical formula of both types of folic acid is the same – only the source is different. Still, for many people this difference is significant.
Popular Folic Acid Supplements
Sundown Naturals Folic Acid Tablets
Sundown Naturals are folic acid tablets that provide 400mcg of folic acid each. The tablets are suitable for both vegans and vegetarians since they don’t contain any ingredients from animal by-products.
Get more info and read customer reviews on Amazon: Sundown Naturals Folic Acid Tablets
Active ingredients: 1 Tablet contains 400mcg of Folic Acid.
Other ingredients: Vegetable cellulose, dicalcium phosphate; contains <2% of: silica, vegetable magnesium stearate
Futurebiotics Folic Acid
Futurebiotics folic acid supplement contains 800 mcg of folic acid per tablet.
These tablets are somewhat special among the folic acid supplements since they contain folic acid derived from lemon peel - large majority of other supplements contain folic acid that is made from scratch in laboratories.
Lemon peel has high levels of natural folate. Once this folate goes through the extraction process, it converts into folic acid. This substance is chemically identical to the synthetic folic acid – only the source is different. However, the difference may be important to you if you are looking for supplements wholly made from natural ingredients.
The lemons that are used for Futurebiotics folic acid tablets are organically grown on privately owned farms. No pesticides or chemical fertilizers are used.
The lemon extract is water based, which means that it doesn’t contain any residues of solvents or other impurities. All added ingredients in the tablets are derived from organic rice (maltodextrin, rice concentrate and extract). The end product is USDA organic certified.
Futurebiotics folic acid tablets are processed in FDA inspected facility and go through several tests to ensure safety and potency.
Get more info and read customer reviews on Amazon: Futurebiotics Folic Acid
Active ingredients: 1 tablet contains 800mcg of folic acid (from organic lemon peel extract).
Other ingredients: Organic rice maltodextrin, organic rice concentrate, organic rice extract
There is quite a lot of confusion about methylfolate supplements due to the various names that are being used for them. Some people simply say folate or methylfolate; others use the terms 5-MTHF and 5-methyltetrafolate. However, all of these describe the same type of folate.
Methylfolate is the most bioavailable form of folate supplement. This means that once you ingest it, your body can readily use it (unlike folic acid and folinic acid that both need to be converted into more bioavailable form first).
In the past, there was a major problem with folate supplements. The ones that were available were very susceptible to oxidation and degraded really quickly. Nowadays, however, there are several patented forms of methylfolate that are both stable and bioavailable. Below you can take a look at them and see how they differ.
How Do Brands of MethylFolate Differ?
Major patented brands of methylfolate include:
- Extrafolate S
All of these are a form of methylfolate. Quatrefolic is the glucosamine salt of methylfolate and both Metafolin as well as Extrafolate S are calcium salts of methyfolate.
Quatrefolic is the one that is most commonly used and is considered the most recent generation in methyfolate supplements.
It has a slightly better absorption and bioavailability than the calcium salts of methyfolate (in one study (3) the peak concentration of folate in plasma was 1.8 times higher than the same measure for calcium salt and AUC – a common measure of bioavailability - was 1.12 times). However, in the same study both of these forms of methyfolate were proven to be much superior in both absorption and bioavailability to folic acid supplements.
Metafolin is the methyfolate supplement that is marketed for mental conditions since it is the main component in the antidepressant drug Deplin. Still, both calcium and glucosamine salt of methyfolate are able to cross the blood brain barrier and enter straight into brain cells – and can thus be of benefit for brain and mental health.
Besides the above mentioned brand names, you can also come across other generic forms of methyfolate supplements. Typically, they are cheaper than the patented brands and seem to provide better value for money. However, it is important to remember that their bioavailability and other characteristics are not supported by scientific studies.
If you decide to get the generic form of methylfolate, the label should specify which form it is. The forms with the best bioavailability are L-methyltetrafolate or 6s-methyltetrafolate. Avoid forms that don't have such designation. These include: D-5-Methyltetrahydrofolate, 6(R)-L-MTHF and 6(R)-L methyltetrahydrofolate.
Quatrefolic Folate Supplements
Quatrefolic is glucosamine salt of (6S)-5-methyltetrahydrofolate. It has been developed by Gnosis S.p.A and is protected by international patents (USA patent granted in 2011). Quatrefolic is sold and distributed by several well known supplement companies including Doctor's Best, Life Extension, Jarrow, and others.
Quatrefolic is also called the 4th generation of folate supplements since it is the most recent to come to the market. It is very stable and has a long shelf line. Its main benefit is that it is highly soluble in water. This in turns means that more of the Quatrefolic gets absorbed in the body, which leads to superior bioavailability of this form of folate.
Life Extension Optimized Folate
Life Extension Optimized Folate is a hugely popular methylfolate supplement. It provides 1.000 mcg of Quatrefolic folate per capsule – which is quite a lot since many of the other Quatrefolic products contain 400mcg of Quatrefolic per capsule.
Life Extension Optimized folate supplement is suitable for both vegans and vegetarians as it doesn’t contain any ingredients from animal sources. It is also free from GMO ingredients. It comes from a reputable supplement company and is manufactured in GMP certified facility. The product is regularly tested for safety and potency.
Get more info and read customer reviews on Amazon: Life Extension Optimized Folate
Active ingredients: 1 tablet contains 1000mcg of folate (as [6s]-5-methyltetrahydrofolic acid, glucosamine salt).
Other ingredients: Microcrystalline cellulose, dicalcium phosphate, croscarmellose sodium, silica, vegetable stearate, stearic acid
Other Popular Quatrefolic Supplements include:
Doctor's Best Best Fully Active Folate: Contains 400mcg of Quatrefolic per capsule. It also has 40 mg of Vitamin C per capsule as an additional antioxidant support (for greater stability of the supplement). Capsules are made from cellulose.
Jarrow Formulas Methyl Folate: Provides 400mcg of Quatrefolic folate per veggie capsule. The other ingredients are cellulose and magnesium stearate from vegetable source.
Seeking Health L-5-MTHF: Contains 1.000 mcg of Quatrefolic folate per vegetable capsule. It also contains ascorbyl palmitate (vitamin C) and amino acid L leucine for stability. This supplement is a good alternative to Life Extension Optimized Folate.
Metafolin is calcium salt of (6S)-5-methyltetrahydrofolate. It is developed and produced by Merck Millipore.
Metafolin is a stable, water soluble form of methylfolate. It has a bit lower absorption rate and bioavailability than the glucosamine salt of methylfolate – Quatrefolic; still, the difference is not very significant.
Metafolin is the same type of methylfolate that makes up the prescription drug for depression, Deplin. However, the doses in Deplin are much larger than the doses in Metafolin OTC supplements. Deplin comes in 2 strengths: 7.5 mg and 15 mg, while the Metafolin OTC supplements contain up to 1mg of Metafolin per capsule.
Metafolin is protected by a set of patents and licensed to several brand name supplement companies. Below you can find a brief overview of popular methyfolate supplements that contain Metafolin.
Solgar Metafolin tablets contain 800mcg of Metafolin each.
The tablets are suitable for both vegans and vegetarians. They are meant to be swallowed whole with a glass of water; however, some people prefer to chew them. They have a mildly sweet flavor, which comes from the ingredient mannitol (type of sugar).
Get more info and read customer reviews on Amazon: Solgar Folate
Active ingredients: 1 tablet contains 800mcg of folate (as Metafolin).
Other ingredients: Mannitol, microcrystalline cellulose, vegetable stearic acid, vegetable cellulose, silica, vegetable magnesium stearate
Other Metafolin Suppplements include:
Douglas Laboratories Methyl Folate: Offers 1.000 mcg of Metafolin per tablet (suitable for vegetarians)
Pure Encapsulations Folate 400: Contains 400mcg of folate Metafolin per capsule. Capsules are hypoallergenic and made from cellulose. The supplement is without any added ingredients, so it is a preferred choice if you want to limit your intake of fillers and flow agents.
Extrafolate S comes from Gnosis, the same company that manufactures Quatrefolic. Extrafolate S is calcium salt of (6S)-5-methyltetrahydrofolic acid and has been developed as an alternative to Metafolin. However, Metafolin still remains the most widely used calcium salt methylfolate supplement.
Thorne Research - 5-MTHF
Thorne Research 5-MTHF is a methylfolate supplement that contains Extrafolate S (calcium salt methylfolate). Each capsule provides 1 mg of Extrafolate S.
The supplement is produced by Thorne Research, which is one of the leading manufacturers of nutritional supplements. Their products are rigorously tested and have NSF certification. Important plus is that Thorne supplements don’t contain any magnesium stearate, which is noteworthy to people who try to decrease the intake of this commonly used pharmaceutical lubricant.
Get more info and read customer reviews on Amazon: Thorne Research - 5-MTHF
Active ingredients: 1 capsule contains 1mg of Folate (as L-5-Methyltetrahydrofolate).
Other ingredients: Microcrystalline cellulose, hypromellose (derived from cellulose) capsule, leucine, silicon dioxide
Methylfolate Supplements With Vitamin B12
People often take folate supplement thatis combined with vitamin B12. The reason for this is that these 2 vitamins work synergistically to convert the amino acid homocysteine to methionine. This process is vital to many important functions in the body and supports brain and cardiovascular health.
When you are looking for supplements that include vitamin B12, you need to be careful to choose B12 in the form of methylcobalamin and not in the more common form cyanocobalamin. Unlike the naturally occurring methylcobalamin, cyanocobalamin is synthetically made and involves a cyanide molecule. The quantities of cyanide in one supplement pill are small strictly looking from toxicological point of view. Still, your body will need to remove it, which puts it under unnecessary stress.
The supplements presented below contain folate in its most bioavailable form methylfolate. The brand names of folate are Quatrefolic or Metafolin. All of these supplements also contain B12 in its recommended form – methylcobalamin.
Popular methylfolate and B12 (methylcobalamin) supplements are:
Active B12 Lozenge With L-5-MTHF: the most popular B12 and methylfolate supplement. Each lozenge contains 800 mcg Quatrefolic folate and 1000 mcg methycobalamin.
Jarrow Formulas Methyl B-12/Methyl Folate: a major plus of this supplement is that also contains B6 (in the form of P-5-P), which is an important coenzyme in the conversion of homocysteine to methionine. Each lozenge has 400 mcg of Quatrefolic methylfolatefolate, 1000 mcg methylcobalamin and 1.5 mg of vitamin 6.
Pure Encapsulations - B12 Folate: Provides 800mcg of Metafolin methylfolate and 800 mcg of methylcobalamin per hypoallergenic, vegetarian capsule.
Activated B12 L-5-MTHF and Methylcobalamin: Lozenges with 800mcg Metafolin methylfolate and 1 mg methylcobalamin. They contain a type of sugar - mannitol, which gives them a mildly sweet taste.
Multivitamins, B Complex Vitamins and Prenatals with Methylfolate
Large majority of vitamin packs contain folate in the form of folic acid. However, there are some supplements that have the bioavailable methylfolate.
Multivitamins with methylfolate include:
Thorne Research - Basic Nutrients 2 / Day (Basic vitamins and minerals with methylfolate)
Prenatal vitamins with methylfolate:
Best Nest Prenatal Vitamins (With added raspberry leaf for toning the uterus, ginger and chamomille for nausea)
Thorne Research - Basic Prenatal (Prenatal vitamins with methylfolate and methylcobalamin)
SmartyPants (Prenatal vitamins with methylfolate in chewable gummy bears; with added Omega 3 fatty acids for healthy brain development)
B complex vitamins with methyfolate:
Pure Encapsulations B-Complex Plus (Contains B complex vitamin with methylfolate Metafolin)
Jarrow Formulas B-right Complex (Contains Quatrefolic; minimized odor due to microencapsulation)
Doctor's Best Fully Active B Complex (With added vitamin C for greater stability)
Folinic Acid Supplements
Folinic acid is also known as calcium folinate or Leucovorin.
Folinic acid is one of the forms of folate that can be found in food. It is more bioavailable than folic acid (less than methylfolate, though) since it is more quickly and easily converted into the form of folate that is circulating in the body (called 5-methyltetrafolate). Folinic acid can enter the cells where it is used for production of DNA and RNA.
Folinic Acid Uses
Folinic acid is commonly used for treating folate deficiency.
Folinic acid is also given to people with cancer together with chemotherapy drug fluoroucacil (used for treating colon, rectal, head, neck and esophageal cancers). The reason why they are given together is that folinic acid enhances the anti-cancer effects of fluoroucacil (it helps the medication to stay longer in the cancer cells and thus prolongs its action).
Sometimes folinic acid is also given with the chemotherapy medication methotrexate in the so called »rescue therapy«. Folinic acid helps to recover healthy cells from the toxic effect of methotrexate. It is given 24 hours after methotrexate, so that it doesn't counteract the action of methotrexate on the cancer cells.
Folinic acid is also used for reducing the side effects of methotrexate in people who take it for psoriasis or rheumatoid arthritis. In these conditions, folinic acid can be taken at the same time as methotrexate as it doesn’t cancel out its anti-inflammatory effect.
People also take folinic acid for mood support and reducing anxiety.
Folinic acid has also been successfully used for improving the symptoms of autism spectrum disorder (4), treating infants with cerebral folate deficiency (5), and schizophrenia associated with folate receptor antibodies (6).
Popular Folinic Acid Supplements
Source Naturals MegaFolinic
Source Naturals MegaFolinic tablets contain 800mcg of folinic acid each. They are suitable for vegans and vegetarians as they don’t contain any ingredients derived from animal by-products. The product is manufactured in facility that adheres to GMP (good manufacturing practice) standards.
Get more info and read customer reviews on Amazon: Source Naturals MegaFolinic
Active ingredients: 1 tablet contains 800mcg of folinic acid
Other ingredients: Microcrystalline cellulose, stearic acid and magnesium stearate
Other Popular Folinic Acid Supplements are:
Seeking Health Folinic Acid: The supplement contains 800mcg of folinic acid per capsule; comes with added C vitamin (ascorbyl palmitate) for increased stability.
Folixor: a combination of folic and folinic acid together with vitamin B6, B12 and amino acid L-leucine.
- Quatrefolic. http://www.quatrefolic.com/
- Extra Folate S. http://www.gnosis-bio.com/extrafolates.php
- Metafolin. http://www.merckmillipore.com/INTL/en/products/small-molecule-pharmaceuticals/bulk-api/folates/metafolin/key-benefits/83Ob.qB.MZEAAAFNTWxItHt_,nav
- Leucovorin (folinic acid). http://www.macmillan.org.uk/cancerinformation/cancertreatment/treatmenttypes/chemotherapy/individualdrugs/leucovorin.aspx
- Folinic Acid. http://chemocare.com/chemotherapy/drug-info/folinic-acid.aspx
- The Follies of Folate: What You Really Needs to Know in a Nutshell. http://www.needs.com/product/NDNL-1410-01/l-folate
- James A Greenberg and Stacey J Bell. Multivitamin Supplementation During Pregnancy: Emphasis on Folic Acid and l-Methylfolate. (2011)
- James A Greenberg, Stacey J Bell, Yong Guan, and Yan-hong Yu. Folic Acid Supplementation and Pregnancy: More Than Just Neural Tube Defect Prevention. (2011)
- Miraglia N, Agostinetto M, Bianchi D, Valoti E. Enhanced oral bioavailability of a novel folate salt: comparison with folic acid and a calcium folate salt in a pharmacokinetic study in rats. (2016)
- R E Frye, J M Sequeira, E V Quadros, S J James, and D A Rossignol. Cerebral folate receptor autoantibodies in autism spectrum disorder. (2013)
- Al-Baradie RS, Chaudhary MW. Diagnosis and management of cerebral folate deficiency. A form of folinic acid-responsive seizures. (2014)
- Ramaekers VT, Thöny B, Sequeira JM, Ansseau M, Philippe P, Boemer F, Bours V, Quadros EV. Folinic acid treatment for schizophrenia associated with folate receptor autoantibodies. (2014)