Vitamin B12 2000mcg

Cyanocobalamin is the form most Australians already take, often without choosing it. These are the questions our naturopaths ask in store, including the two situations where this particular form is the wrong one.

A good fit if

• You eat little or no animal food and want the form with the most evidence behind it
• Your kidneys work normally and there's no inherited optic nerve condition in your family
• You already take a B complex or multivitamin that contains it and want to understand what you're taking
• You're comfortable with your body doing the conversion step itself
• Your doctor is monitoring your B12 and you want a tablet option for keeping your levels up to discuss with them

Check with us first if

• You have reduced kidney function or are on dialysis. Concern has been raised about high-dose cyanocobalamin in this group, and other forms of B12 have been suggested instead.
• You take metformin, a proton pump inhibitor or an H2 blocker. These reduce B12 absorption, so it's worth checking your level rather than assuming a supplement covers it.
• You already take a B complex, multivitamin or fortified drink. Cyanocobalamin is in all three, so adding 1,000 µg on top is worth deciding on purpose.
• You also take high-dose folate or folic acid. Large doses of folate can correct the blood test picture while leaving nerve damage untreated.
• A blood test shows you have anaemia and the cause hasn't been found.
• You're pregnant or breastfeeding and eat little or no animal food, or you're choosing a form and dose for a child.
• You take any prescription medicine at all. Check with your doctor, pharmacist or our naturopaths first.

• Inside a B complex or multivitamin. Best known for: The quiet majority. Most people taking cyanocobalamin didn't choose it on purpose. Absorption: Small amounts, absorbed at the efficient end of the range. Typical use: About 5 µg in a standard B complex, and up to 50 µg in a high-strength one.
• Standalone low-dose tablet. Best known for: A modest single-nutrient dose if you only want B12. Absorption: Roughly a hundred times what you need each day, which is why less is absorbed per microgram. Typical use: 100 µg tablets, usually one or two a day with meals.
• High-dose tablet or sublingual. Best known for: The 1,000 µg pack that fills most of the shelf, often sold to dissolve under the tongue. Absorption: Only a small percentage of a dose this size is absorbed, which is exactly why the dose is this size. Typical use: 1,000 µg a day; under-the-tongue forms are convenient rather than measurably better.
• Added to fortified foods. Best known for: The form added to cereals, nutritional yeast and some plant-based milks. Absorption: Already free, so it doesn't need stomach acid to release it from food protein first. Typical use: Not something you choose off the shelf, but it counts toward your intake.
• Cyanocobalamin injection. Best known for: The prescription option used when absorption has failed. Absorption: Bypasses the stomach, intrinsic factor and the gut receptor completely. Typical use: A medical decision made by your doctor, not a retail one.

Reference values. The NHMRC recommended intake is 2.4 µg a day for adults, with the full figures for age, pregnancy and breastfeeding on our vitamin B12 page. Those figures are for the vitamin, not this form, so 2.4 µg of any form of B12 counts the same.

Typical supplemental range. Australian labels step up in clear levels: about 5 µg of cyanocobalamin in a standard B complex, 50 µg in a high-strength one, 100 µg in a low-dose tablet on its own, and 1,000 µg in high-dose tablets and under-the-tongue products. Unlike a mineral, the number on the label is the cyanocobalamin itself, so there's no conversion to do. Just compare the microgram figures directly.

Upper level. The NHMRC hasn't set an upper limit, and its reason is worth quoting in full: "There are insufficient data to allow setting of a UL. There is no evidence that the current levels of intake from foods and supplements represent a health risk." Australia's permitted ingredients list (Schedule 1) sets no maximum daily dose either, which is why 1,000 µg products can be sold here.

Worth knowing. A bigger microgram number doesn't mean a proportionally bigger absorbed dose. Your body absorbs a smaller share as the dose goes up, which is the whole reason high-dose products exist. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• Fortified breakfast cereal: about 0.6 µg per serving where the cereal is fortified to 25 per cent of the US Daily Value; Australian fortification levels are voluntary and differ by brand
• Fortified nutritional yeast: 8.3 to 24 µg per quarter cup depending on the brand, and some Australian nutritional yeast is not fortified at all
• Fortified plant-based milks: fortification is voluntary in Australia, so two soy or oat milks on the same shelf may differ entirely: the nutrition panel is the only guide
• Animal foods: supply naturally occurring cobalamins rather than cyanocobalamin; the amounts are listed on the vitamin B12 page

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• Early Leber's disease (an inherited optic nerve condition). Prescribing information records severe, rapid optic nerve damage in people treated with cyanocobalamin; use another form under medical advice.
• Known sensitivity to cobalt or vitamin B12. Don't take it; there's a risk of anaphylaxis.
• Any change in your vision. Stop taking it and get a medical check.
• Poor kidney function and dialysis. Concerns have been raised about toxicity from high-dose cyanocobalamin, and other cobalamin forms are suggested.
• Pernicious anaemia or diagnosed poor absorption. Oral supplements must not replace prescribed injections.
• Nerve symptoms such as numbness, tingling, unsteadiness or memory changes. These need a medical check.
• Anaemia without a known cause. Find out the cause before taking supplements.
• Taking high-dose folate at the same time. It can correct one type of anaemia (megaloblastic) while leaving nerve damage untreated.
• Metformin, proton pump inhibitors and H2 blockers. These reduce B12 absorption, so monitoring is advised.
• Adding a high-dose tablet on top of a B complex, multivitamin or fortified foods that already contain it.
• Pregnancy and breastfeeding on a diet with no animal foods, and babies and children. The dose and form differ.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.