After I did some research on folate vs. folic acid, I've decided that this particular form of that supplement is not at all safe, and I'm throwing it out and will never purchase it again. Below are my discoveries that led to that decision. Folate is a vital B vitamin. A deficiency of this vitamin is implicated in developing atherosclerosis or having a heart attack or stroke because, in conjunction with vitamins B6 and B12, it is essential for lowering homocysteine levels. Folate deficiency can also lead to birth defects in pregnancy, macular degeneration, depression, and accelerated aging. Folate consumed from natural, whole, unprocessed foods is safe, and there are no known examples of overdosing on folate-rich foods, very likely because most Americans rarely eat very much of these nutritious foods. They include: beans, lentils, spinach, asparagus, Romaine lettuce, avocado, broccoli, cauliflower, mango, oranges, turnip greens, mustard greens, parsley, collard greens, and beets. In purchasing supplemental folate, it is crucial to know the difference between the terms, folate and folic acid. Folate is often used as a generic term for a group of water soluble B vitamins which are also known as B9. Folate is also the term specifically used for the form of B9 that naturally occurs in food. Folic acid is an oxidized, synthetic compound which processed-food manufacturers in the USA have been mandated since 1998 to fortify food with in order to prevent neural tube defects in newborns. Natural folate from food sources is metabolized in the mucosa of the small intestine to tetrahydrofolate (THF), the body's only usable form of folate. In contrast, folic acid is first converted to methylation in the liver. From there, it must be converted by the liver to THF, via the enzyme, dihydrofolate reductase. If there is very high intake of folic acid from fortified food or nutritional supplements, there might not be enough of this enzyme to metabolize all of the folic acid. Other issues which can lead to this problem include the following: a person has a genetic mutation of the MTHFR gene, which interferes with production of the MTHFR enzyme; a person suffers from Liver disease or takes certain pharmaceuticals which interfere with folic acid metabolism. These medications include: anticonvulsants (such as phenytoin, primidone, carbamazepine or valproate), metformin (prescribed to control blood sugar in type 2 diabetes), methotrexate (an anti-cancer drug, also used to control inflammation associated with Crohn's disease, ulcerative colitis and rheumatoid arthritis), sulfasalazine (used to control inflammation associated with Crohn's disease, ulcerative colitis and rheumatoid arthritis), triamterene (a diuretic), oral contraceptives. All of the above causes can result in an unsafe amount of unmetabolized folic acid entering the bloodstream. Research has indicated that high amounts of unmetabolized folic acid within the bloodstream is implicated in the growth and spread of cancer. Scientists believe that this is due to two possible reasons: it stimulates the growth of premalignant and malignant cells and tumors, and it decreases the effectiveness of natural killer cells, which play a major role in the destruction of tumor cells. Since the MTHFR gene mutation is growing ever more prevalent in the general population, it is becoming increasingly common to find supplemental folate that can be instantly utilized by the body without need for any chemical conversion in the small intestines or liver because it is in the form of THF and is called 5-methyltetrahydrofolate (5-MTHF). There are various names for this ingredient besides the generic name 5-methyltetrahydrofolate (5-MTHF), including another generic name, methylfolate, and the brand names, Quatrafolic, Extrafolate, and Metafolin. It is also important to purchase a specific chemical structure of folate which has the best bioavailability, the kind with an "L-" or "6S-" in front of the folate word. Any form with "D" in front of the folate word should be avoided. Note that the form of folate in the product Solgar Folate As Metafolin is "l-methylfolate," under the brand name, "Metafolin." This means it is a very bioavailable form of folate. Another brand that has the best form of folate is Jarrow Formulas Methyl Folate 5-MTHF . There have been many scientific studies of folate over the past few decades,and a similar situation is found for nutraceuticals as is very common with pharmaceuticals, to wit: There is a noticeable difference between the observable positive effects when a drug or supplement is administered in vitro (in a cell culture) as compared to in vivo (in living animals or humans). Cell studies virtually always show far greater positive results than do animal and human tests. As a result of this variation, it is hard to predict how much positive result any given person may experience from any pharmaceutical or nutraceutical they ingest, as well as the degree of any potential negative side effects. Fortunately, unlike for pharmaceuticals, nutraceuticals that are properly processed in well-maintained factories don't kill up to 45,000 people per year in the USA alone as pharmaceuticals routinely do. In fact, the only documented cases of deaths attributable to nutraceuticals, and there are very few of these, are from herbal weight-loss products which are often adulterated illegally with drugs or consist of formulations which rely overmuch on adrenaline-pumping herbs and caffeine