This supplement comes in the form of a lozenge that is dissolved under the tongue. It has a pleasant taste. It is interesting to me that vitamin B12, or any B-series supplement such as this one containing it, is the main supplement, other than melatonin, which is almost universally offered as a sublingual. It would seem to be a good idea to have far more supplements than those be liquid or easily dissolved under the tongue for maximum absorption. The blood vessels under the thin skin of the tongue are very near to the surface, which allows anything taken sublingually (including medications) to absorb instantly into the blood stream. In this manner, they avoid having to pass through the stomach, the liver, and the small intestines before getting into the bloodstream, so they are much more quickly and fully absorbed. This isn't quite as effective as IV or an injection of B vitamins, but certainly a less invasive way to receive them. This particular tripartite formulation is an intriguing type of B vitamin supplement because it contains a combination of three different crucial B vitamins: B6 as pyridoxal 5-phosphate 2.5 mg B12 as methylcobalamin 5000 mcg (5 mg) Folate as Quatrefolic (6S)-5-methyltetrahydrofolic acid glucosamine salt 800 mcg It makes sense to create a one-stop-shopping supplement for preventing heart disease and stroke which contains B6, B12, and folate, because these three B vitamins together are an important combination having scientifically proven value in lowering homocysteine levels. As you may know, elevated homocysteine levels are implicated in the development of atherosclerosis, Heart attack and stroke because they contribute to plaque formation by damaging arterial walls. Folate also helps prevent birth defects in pregnancy, depression, macular degeneration, accelerated aging, and other serious conditions. This form of B6, pyridoxal 5-phosphate (P5P) is more bioavailable than standard vitamin B6, pyridoxine. In a state of health, the liver converts pyridoxine, consumed from either food or supplements, into its active form, P5P. But since some people are not healthy enough for their livers to make this conversion, many supplement manufacturers have moved to utilizing the active form of B6, P5P, to spare the liver. Methylcobalamin is also the most bioavailable form of B12. There are other reputable companies besides Jarrow who sell this form of B12, including Solgar, in particular, whose nugget form I really like. The form of folate used in this supplement is folate, rather than folic acid. Folic acid is a synthetic compound which processed-food manufacturers in the USA have been mandated since 1996 to add to food in order to prevent neural tube defects in newborns. Natural folate from food sources is metabolized in the mucosa of the samll intestine to tetrahydrofolate (THF), the body's only usable form of folate. In contrast, folic acid is converted via the methylation cycle in the liver to THF by means of the enzyme dihydrofolate reductase. If there is a very high intake of folic acid from fortified food or nutritional supplements, there might not be enough of this enzyme in the body to metabolize the folic acid. Another issue is that some people have an anomaly of the MTHFR gene, which interferes with the production of the MTHFR enzyme. There are also various pharmaceuticals which interfere with folic acid metabolism, for example, anticonvulsants and oral contraceptives. All of the above can result in unsafe amounts of unmetabolized folic acid entering the bloodstream, which is implicated in the growth and spread of cancer, most likely because it stimulates premalignant and malignant cells and tumors while simultaneously decreasing the effectiveness of the natural killer cells in the immune system, which play a major role in the destruction of tumor cells. Discovery of these issues this has led to the creation of the 5-MTHF forms of folate, which this supplement contains. There are several kinds of 5-MTHF on the market. This particular supplement employs Quatrafolic, which is manufactured by Gnosis. Qutrafolic is (6S) 5-methyltetrahydrofolate (5-MTHF) or L-methylfolate, which uses glucosamine salt as compared to 5-methyltetrahydrofolic acid, calcium salt (5-MTHF-Ca), which had been on the market prior to this formulation. Under regulatory guidelines, 5-MTHF-glucosamine is used in a maximum recommended dosage of up to 1.8 mg/day, which equates to 1 mg 5-MTHF and 0.8 mg glucosamine. The glucosamine salt is the primary differentiation between this formulation and that of Metafolin, which is manufactured by Merck under the same names of (6S)-5-methyltetrahydrofolic acid or L-methylfolate, as well as L-5-methyl tetrahydrofolate and/or Levomefolic acid. Metafolin contains calcium salt rather than glucosamine salt, and supplement manufacturers which utilize this ingredient are restricted by Merck to no more than 1 mg (1000 mcg) per dose. As you can see from the label, the dose for this vitamin in this supplement is 800 mcg. Some experts claim that a lower percentage of folate is absorbed from this glucosamine form as compared to the calcium salt version, and some say the glucosamine form, such as is contained in this supplement, is better absorbed. Clearly, Jarrow has decided that the glucosamine form is better. I personally would feel comfortable taking either form because both are the 5-methyltetrahydrofolic (5-MTHF) form of folate, which is best absorbed by the body