Doctor’s Best Methyl Folate with Quatrefolic 800 mcg – 60 Veggie Capsules


  • Best Fully Active Folate provides MTHF (5-methyltetrahydrofolate), the folate form most directly required for DNA regulation and other fundamental metabolic processes. supplementation with 5-MTHF is highly preferable
  • Vitamin C is included for added stability.
  • Quatrefolic: Featuring 4th generation development in folate delivery, our patent-pending technology formula features increased stability and bioavailability
  • Benefits: Healthful diets with adequate folate may reduce the risk of having a child with a brain or spinal cord defect
  • Convenient Veggie Capsules: Each veggie capsule delivers 400 micrograms (mcg) of methyl folate; Take 1 capsule per day, with or without a meal, or as directed by your qualified healthcare professional
  • 60 Capsules
  • Made in USA

Out of stock


Doctor’s Best Fully Active Folate 800 with Quatrefolic contains Quatrefolic, the glucosamine salt of (6S)-5-methyltetrahydrofolate, the most bioavailable form of folate, that provides greater stability and water solubility.*

Our body cannot synthesize folate and due to its water-soluble nature, the body stores folate to a limited extent.

Folic acid, and food folate, needs to be converted to its metabolically active form to be utilized by the body. Quatrefolic is the metabolically active folate, making it more efficient than folic acid for maximized benefits!*

Folate is an essential vitamin to support DNA, proper cell division, cardiovascular, mental and emotional well-being.* Vitamin C is included for added stability.*

Fully Active Folate supplies the B vitamin folate as [6S]-5-methyltetrahydrofolic acid (MTHF). This is the body’s most fully active folate nutrient, its most important folate reservoir, and the only folate form biochemically identical to the MTHF present in the body. This supplement features Quatrefolic**, human-identical MTHF, as a glucosamine salt. This next-generation supplement guarantees the intricate MTHF structure with improved stability over the earlier-generation calcium salt of MTHF.

Named after the Latin word for leaf (‘folium’), folate is the collective term for a family of pteroylglutamate nutrients that are most concentrated in leafy vegetables. The body cannot make folate on its own and must obtain it from foods or dietary supplements, with possible small contributions from intestinal bacteria. Foods supply only limited amounts of folates and these are generally not well absorbed. Of the folates that are absorbed, almost all are converted to MTHF. The Quatrefolic** brand of MTHF in this supplement is the most stable and best-absorbed form available anywhere.

Some enzymes use methyl available from MTHF to produce certain purines and pyrimidines, which are building blocks for the bio-synthesis of DNA and RNA. DNA is the genetic ‘blueprint’ for making functional proteins, while RNA helps translate the blueprint into the final protein structure. MTHF is the body’s ultimate methyl reservoir, its most dependable source for obtaining methyl groups to build DNA and RNA, and from them proteins and phospholipids as needed.

A gene is a length of DNA with various attached proteins that help regulate the DNA. Various enzymes attach or detach methyl groups to and from the gene’s DNA and its associated proteins, as part of a sophisticated regulatory process called epigenetics. As the term implies, epigenetics is higher-level gene control-in part, the use of methyl as a ‘toggle switch’ for turning each gene off or on.5 Adding methyl turns the gene off, removing methyl turns it on.

Every cell has a distinctive epigenetic pattern that is translated into specific protein patterns, which produce its unique functional profile. In humans with MTHF deficiency, available methyl is limited and can contribute to genetic and epigenetic abnormalities. DNA strands can break, DNA repair can be impaired, and other changes can occur that affect gene and chromosome structure.10-12 The deleterious genetic effects of mild folate deficiency have been compared to X-ray exposure (equivalent to approximately 10 times above the maximum X-ray limit considered safe).

In studies of Australian adults, the third of the population with the lowest folate showed significantly more of these folate deficiency effects. Folate deficiency can have epigenetic effects that cascade to cause ‘downstream’ effects on cell structure and function.

The Brain Relies Heavily on MTHF:

MTHF plays a crucial role in the brain’s early development and its ongoing plasticity-the all-important capacity to adapt to changing life circumstances. The brain has very high demand for MTHF, and expends energy to import it across the blood-brain barrier using specialized transport proteins. The brain also homeostatically regulates the MTHF in its cerebrospinal fluid (CSF). MTHF levels in the CSF are commensurate with brain health and overall health and wellbeing.

The brain’s reliance on MTHF starts from its very beginning. As the fetal brain begins to form (at about 4-5 weeks after conception) it draws MTHF from the mother’s pool. But the body actually stores very little MTHF, so the mother can soon become folate deficient. There is a well- established link between maternal folate deficiency and fetal neural tube defects.14 MTHF deficiency also can afflict newborn babies. Since common foods supply limited amounts of folate, the pregnant women is well advised to supplement with fully active folate-MTHF.

In adults, adequate folate status appears linked to brain structure, including appropriate size of the hippocampus and the amygdala, brain zones important for memory and other cognitive functions. In this manner, adequate folate intake supports maintenance of memory, mood balance, and all the other higher brain functions.

MTHF Is A Core Nutrient for Mood Enhancement:

Several population (epidemiologic) studies in the U.S. and other countries have linked low folate levels to difficulties with mood management.3 When those receiving the highest amounts of folate were compared with those receiving the lowest amounts, the highest folate status was associated with the least severe occurrence of mood difficulties. MTHF is gaining mainstream attention as a nutritional component of integrative mood enhancement.

Methyl from MTHF is essential for the body’s production of SAMe (S-adenosylmethionine). SAMe is a highly energized and versatile methyl donor, important for DNA and RNA regulation, for cell membrane phospholipid synthesis, for synthesis of the key antioxidant glutathione, and for numerous other methyl modifications of key biological molecules. SAMe supports mood management and many other important life functions.

A Top Priority Nutrient During Pregnancy

In response to the wide prevalence of folate deficiency, the U.S. government instituted food fortification with synthetic folic acid in 1998. Despite these efforts, maternal MTHF deficiency is still an issue. The U.S. Centers for Disease Control and Prevention recommends all women of childbearing age supplement with folate, especially since the need arises during the first trimester when the woman may not be aware she is pregnant. MTHF has proven superior to folic acid for this application.

In two double blind trials, MTHF (at 400 mcg per day) outperformed equal amounts of folic acid (also at 400 mcg per day) for raising women’s red cell MTHF levels. Surveys indicate less than half of all pregnancies in the U.S. are planned, making it prudent for any woman who could become pregnant to consume sufficient MTHF daily.

Another nutrient often strongly recommended during pregnancy is omega-3 DHA (DocosaHexaenoic Acid).27 A ­­study with pregnant women found that those who supplemented with MTHF (400 mcg per day) along with DHA (500 mg per day, with 150 mg per day of EPA), from week 22 until delivery, developed higher levels of blood DHA than those who did not get MTHF.

MTHF Is Superior to Folic Acid For Folate Supplementation:

Unfortunately, as with the natural folates in foods, folic acid has no metabolic or other nutritional value unless converted into MTHF. The enzyme dihydrofolate reductase (DHFR) must do this conversion, though it is not fully adapted for this task since folic acid is hardly found in nature.

Studies with human DHFR show that its folic acid converting activity is weak and varies greatly between individuals. DHFR likely cannot convert more than 250 mcg per day of synthetic folic acid into MTHF. This level of folic acid intake is actually easy to surpass by consuming fortified foods and/or folic acid supplements,so that many people are carrying unconverted, metabolically useless synthetic folic acid in their tissues.

Recent surveys indicate more than one-third of older U.S. adults have unconverted folic acid in their blood. This poses several problems. First, folic acid can negatively interfere with the metabolism of natural folates. Second, folic acid in the blood can mask megaloblastic anemia, a clinical sign of vitamin B12 deficiency, whereas MTHF does not have this effect. Folic acid’s masking of megaloblastic anemia may allow vitamin B12 deficiency to go undetected. Third, folic acid may inhibit natural killer cells, a class of immune cells that help eliminate other cells which have lost growth control.

Another liability of synthetic folic acid is that it is not an antioxidant. Folic acid is a highly oxidized molecule28 in contrast to MTHF which is a highly reduced molecule and a potent antioxidant. This single feature would strongly recommend MTHF over folic acid for human supplementation. Experts have suggested that one important role for MTHF may be to support the ability of skin to cope with “free radical” damage to its DNA by ultraviolet light.

Folate Deficiencies are Widespread:

Folate deficiency is the most prevalent vitamin deficiency worldwide.8 Besides its potentially crippling effects on the brain and on cell and tissue growth regulation, folate deficiency is linked to anemias,intestinal dysfunction, male fertility problems,pollen hypersensitivities, and bone thinning. Folate deficiency is also linked to blood buildup of homocysteine (HCy), which itself is linked to a plethora of other health problems.

Poor dietary folate intake is a common cause of folate deficiency, but intestinal or kidney dysfunctions,smoking, excessive alcohol consumption, oral contraceptive use, and various pharmaceuticals all deplete blood MTHF. Women who previously used certain oral contraceptives can have lower folate in the first trimester of their pregnancy, especially if they smoke.

Another contributor to widespread folate deficiencies is the commonly existing C677T variation in the folate enzyme MTHFR (methylenetetrahydrofolate reductase), which recycles methylenetetrahydrofolate to MTHF. This variation can cause the enzyme to lose well over half its capacity to make MTHF. The C677T variation exists in almost half of the individuals in some white populations, and is also common in some other ethnic groups, such as U.S. Hispanics and Puerto Ricans.41 Individuals carrying C677T invariably have low blood MTHF levels.

MTHF Deficiency Worsens the Homocysteine Threat:

Homocysteine is a highly reactive, free radical-type substance with proven toxic potential.3 It is a normal byproduct of methionine metabolism that can be routinely recycled to methionine using methyl drawn from MTHF. But when methyl is insufficient (as with MTHF deficiency), HCy is not recycled. HCy then accumulates in the blood and other tissues. Therefore, maintenance of HCy levels-through consistent recycling via MTHF-is an important factor supporting cardiovascular health.

Homocysteine levels also typically rise with age.3 In several studies with aging subjects, including one that lasted three years, high HCy was correlated with low MTHF status and with the health of blood vessels that supply the brain. Supplementation with MTHF can lower elevated HCy, thereby supporting brain circulation and cognitive function. A 2009 double blind trial examining the leg circulation compared MTHF versus folic acid (both taken at 400 mcg per day).29 MTHF improved pulse wave velocity (PWV), a measure of arterial health, better than did folic acid.

Everyone Can Benefit From Taking MTHF:

MTHF is the body’s ultimate methyl resource. The human-identical, [6S]-form of MTHF in Best Fully Active Folate is more compatible with human biochemistry than other MTHF forms commercially available. It supplies ample amounts of methyl for the body’s wide range of methyl group applications, helps keep homocysteine at safe levels, and avoids the myriad problems associated with consuming synthetic folic acid.

One capsule taken once a day between meals supplies 400 mcg of highly absorbable Quatrefolic** MTHF. Human studies indicate this daily intake will significantly improve MTHF status regardless of genetic variations in DHFR, MTHFR or other folate handling enzymes. Individuals with life challenges that severely deplete their MTHF stores may do better using higher intakes, under a physician’s supervision.


Vitamin C (as ascorbic acid) 40mg, Folate [from Quatrefolic, (6S)-5-Methyltetrahydrofolic acid, glucosamine salt] 800 mcg, Microcrystalline cellulose, modified cellulose (vegetarian capsule).


Take 1 capsule daily, preferably between meals. Store in a cool dry place.

Additional information

Weight 70 g
Dimensions 5 × 5 × 11 cm


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.