Vitamin B12 Methylcobalamin Drops

Each drop of this liquid provides 86.5 mcg of methylcobalamin, which is 3460% of the nutrient reference value. Take 1 drop per day in water with food, as the label directs. One drop is one serving, and a 100ml bottle holds 1538 servings. A liquid also suits anyone told to start low, since the amount can be raised drop by drop.

Sources: NIH Office of Dietary Supplements; product label.

Methylcobalamin, often shortened to methyl B12, is one of the two forms of vitamin B12 that the body's enzymes use directly. Vitamin B12 is a family of compounds built around an atom of cobalt, which is why they are called cobalamins; the forms differ only in the small group attached to that cobalt. In methylcobalamin that group is a methyl group, and it is the form the enzyme methionine synthase uses to recycle homocysteine into methionine.

Sources: NIH Office of Dietary Supplements.

Methylcobalamin drops suit anyone who wants an active form of B12 that needs no conversion. Cyanocobalamin is the most common form in tablets and fortified foods; it is stable and inexpensive, and the body converts it into the active forms. Hydroxocobalamin is the stored form, retained in the body for longer, and is converted as enzymes need it. NIH finds no evidence that absorption differs between the forms in supplements, so the choice is about form rather than how much gets in. For the stored form, see the hydroxocobalamin liquid; for all three forms in one bottle, see Tri-B12. All five liquids, with the dose per drop of each, are listed together on the vitamin B12 drops page.

Sources: NIH Office of Dietary Supplements; NHS.

Methylcobalamin and adenosylcobalamin are the two active forms of vitamin B12, and each serves a different enzyme. In the cell fluid, methylcobalamin works with methionine synthase, the enzyme that recycles homocysteine. Adenosylcobalamin works inside the mitochondria with the enzyme that handles a step in the breakdown of fats and proteins for energy. These drops contain methylcobalamin only; for the mitochondrial form, see the adenosylcobalamin liquid.

Sources: NIH Office of Dietary Supplements.

Methylcobalamin drops are for people who want the methylation form of B12 specifically, or who have been told by a practitioner to take methyl B12. That includes vegetarians and vegans, who get little of the vitamin from diet, and anyone who wants to start low and build up drop by drop, because a small number of people find this form stimulating at first. Food Standards Scotland names older adults, people who have had stomach or bowel surgery, and vegans and vegetarians as the groups most likely to run short. Anyone who thinks they may be low in B12 should ask a GP for a blood test rather than self-treating.

Sources: Food Standards Scotland; NIH Office of Dietary Supplements.

Methylcobalamin is most often taken with iron, folate or the other B vitamins, and no interaction with iron is listed by NIH. Folate and vitamin B12 work together on homocysteine. NIH flags one combination to avoid: a high intake of folic acid alongside low vitamin B12 has been associated with poorer mental function in older adults. Mayo Clinic advises leaving two hours or more between a vitamin C supplement and vitamin B12. Prescription drugs are the interactions that matter. Proton pump inhibitors and other acid reducers cut absorption of the vitamin from food, and metformin lowers blood levels, so anyone on regular prescriptions should ask a pharmacist first.

Sources: NIH Office of Dietary Supplements; Mayo Clinic.

Methylcobalamin raises the body's supply of vitamin B12 from the first dose, but the store it tops up is large. The body holds 1 to 5 mg of the vitamin, a thousand times or more the daily requirement, and a shortage takes years to develop. Absorption falls as the dose rises: about half of a dose within 1 to 2 mcg is absorbed, but only about 2% of a 500 mcg dose. Taking the drop every day matters more than the time of day. Anyone who started because of a low result should keep to the retest date a GP has set.

Sources: NIH Office of Dietary Supplements; NHS.

A liquid B12 lets the amount be adjusted one drop at a time, and it suits anyone who cannot swallow tablets. Tablets need binders and a coating to hold their shape; this liquid contains only methylcobalamin and purified water. NIH finds the same result whether the vitamin is swallowed or dissolved under the tongue, so these work as sublingual B12 drops held under the tongue, or as a liquid methyl B12 taken in water.

Sources: NIH Office of Dietary Supplements; product label.

Methylcobalamin has no reported side effects at the amounts found in food or supplements. The body does not store the excess: what is not used passes out, which is why no safety ceiling has been needed. UK advice puts the level unlikely to cause harm at 2 mg a day from supplements. Observational studies have linked unusually high blood levels to poorer health outcomes, but trials giving supplements for two to seven years found little or no effect on serious illness or death rates. Anyone pregnant or breastfeeding, or taking prescribed tablets, should speak to a GP or pharmacist first.

Sources: NIH Office of Dietary Supplements; Food Standards Scotland.