Cobalt Glucoheptonate

Feed mineral companies make it for cattle and sheep rations, because rumen microbes need cobalt to build vitamin B12. It is a manufactured chemical, not a leftover: cobalt carbonate reacted with an acid, then dried.^4,5

1. 01 // Source Cobalt carbonate The patented recipe starts with cobalt carbonate and glucoheptonic acid in water, two moles of acid to one of cobalt carbonate.
2. 02 // Process Reacted and filtered The cobalt carbonate is added to the stirred acid solution, stirred for 15 minutes, then filtered.
3. 03 // Process Dried under vacuum The liquid is concentrated under reduced pressure at 40°C, treated with ethanol and dried to a solid.
4. 04 // Output Cobalt glucoheptonate The pure compound tests at 11.3% cobalt. A commercial version sold to feed makers is diluted to about 2.5% cobalt.

1. 01

   Carried over from livestock

   Cobalt belongs in feed for ruminants, horses and rabbits, which make B12 in the gut. EFSA's feed panel found no need to add it for any other animal.¹

2. 02

   A longer ingredient list

   Asked why cobalt carbonate sat in a cat food, a nutrition professor guessed it simply gave the brand a 13th ingredient to match competitors. An anecdote, but no nutritional reason exists.^1,7

3. 03

   The organic mineral label

   Zinpro sells its minerals as having the highest biological efficacy on the market. Its own patent tested this one only in fermenters simulating a cow's rumen.^4,6

4. 04

   Cheap at trace doses

   A horse feed retailer sells a 2.5% cobalt version at $15.75 per kg. That kilo holds about 25 g of cobalt, enough for 25 tonnes of feed at the EU ceiling.^2,5

How much No source publishes a dog food dose, and EU rules cap total cobalt at 1 mg per kg of complete feed even for species that use it.²

1. Critics say

   Cobalt does nothing for a dog

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   EFSA's feed panel concluded that only animals making B12 in the gut, like ruminants, horses and rabbits, can use cobalt. Dog gut bacteria make B12 in the large intestine, past where it is absorbed, so dogs rely on B12 in food. This rests on mechanism, not a dog trial.^1,3,9

2. Brands say

   Organic chelated cobalt is better absorbed

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   The only test found is the maker's own patent: rumen fermenters fed glucoheptonate at 1 ppm cobalt digested 29.7% of dry matter, against 25.8 to 26.7% for two other cobalt forms and an unsupplemented control. That measures cow microbes, not absorption in a dog.⁴

3. Brands say

   Cobalt helps dogs make vitamin B12

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Bacteria in a dog's large intestine make some B12, but downstream of where it is absorbed. Dogs cannot make it themselves and rely on B12 in food, mainly animal ingredients. No source shows added cobalt raising a dog's B12.^3,9

4. Owners say

   Cobalt in dog food is toxic

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Cobalt has hazards: EFSA calls cobalt(II) genotoxic and carcinogenic, and lists heart, blood and thyroid effects in people. No study has tested trace cobalt in dog food, and the additive EFSA reviewed in 2026 is authorized for ruminants, horses, rabbits and rodents, not dogs.^1,2