Copper in Dog Food: Why It Matters and How to Check Your Dog's Food

By Caroline Buck, Co-founder of Petaluma

Copper has quietly become one of the most talked-about nutrients in dog nutrition, and concern among dog owners is rising fast. Copper is essential for your dog, but a growing body of evidence shows that the amount stored in dogs' livers has climbed steadily over the past century, and diet appears to be the main driver. This is not a reason to panic, but it is a good reason to understand where copper comes from in dog food and how to check the level in what you feed. Here is what the science says and what you can do about it.

Why copper matters for dogs

Copper is an essential trace mineral. Dogs need it to form and maintain red blood cells, to power dozens of enzyme reactions, and for normal skin and coat pigment. True copper deficiency is very rare in dogs today, precisely because commercial foods are supplemented with it.

The concern runs in the other direction: too much. Copper is stored mainly in the liver, so when a dog takes in more than the body can excrete, it accumulates there. Over time this can lead to a form of liver disease called copper-associated hepatopathy. It is treatable when caught early, but it is serious and can be fatal, which is why the balance of copper in the diet matters.

Why veterinarians are concerned now

In 2021, a group of veterinary specialists from several teaching hospitals published a review in the Journal of the American Veterinary Medical Association asking whether it is time to reconsider copper guidelines for dog food (Center et al., 2021). The educator Linda Case gave a clear summary of it on her blog, The Science Dog, in a post called Considering Copper. The trend they describe is striking.

Surveys of average liver copper in dogs across nearly a century tell a consistent story:

For perspective, dogs may show liver injury at concentrations around 600 µg per gram. The review's authors, and more recent work, point to diet as the most likely driver. A 2025 study even found significantly higher liver copper in domestic dogs than in wild coyotes, pointing to excess copper in many commercial foods (2025 study).

Three formulation changes are the leading suspects, in roughly descending order of impact:

• The 1997 switch to more absorbable copper: AAFCO recommended replacing poorly absorbed copper oxide with more bioavailable forms such as copper sulfate and chelated copper, so dogs now absorb more of what is added.
• More organ meat in high-protein foods: liver in particular is extremely copper-dense, and meat-heavy diets have grown more popular.
• More copper-rich plant ingredients: some ingredients, including certain legumes and sweet potatoes, add copper too.

Complicating matters, AAFCO removed its safe upper limit for copper in 2007. Before then the maximum was 250 mg per kg of dry diet. Today there is a minimum of 7.3 mg per kg (dry matter) for adult maintenance, but no official ceiling, which is exactly what the 2021 authors argue should be revisited. For more on how AAFCO profiles work, see our explainer on understanding AAFCO.

Which dogs are most at risk

Genetics play a role alongside diet. Some breeds carry inherited differences in how they process copper and are more prone to accumulation. The Bedlington Terrier is the classic example, with a well-characterized genetic disorder, and others that may be predisposed include the Doberman Pinscher, West Highland White Terrier, American Cocker Spaniel, and Labrador Retriever.

If you have one of these breeds, it is worth being especially aware of copper intake and talking with your veterinarian about monitoring liver health. For most dogs, the takeaway is not alarm; it is awareness. You cannot see copper on a bag, but you can find out how much is in the food.

How to check your dog's food for copper

Copper is not listed on the standard pet food label, but reputable companies will share a full nutrient analysis, usually on their website or on request. Here is how to read it:

• Find the copper value in mg per kg (also written as ppm) on a dry-matter basis.
• Compare it to the reference points: the AAFCO minimum of 7.3 mg per kg, and the 250 mg per kg ceiling AAFCO used before 2007.
• Consider the ingredients: foods built on organ meats can be naturally higher in copper, so ask the company how they monitor it.
• Loop in your veterinarian if your dog is an at-risk breed or you have any concern about liver health.

This is where transparency does the heavy lifting, and it is a standard we hold ourselves to. Petaluma publishes the complete third-party lab analysis for every recipe, copper included. Our Adult Baked recipe measures about 17 mg per kg of copper on a dry-matter basis: above the AAFCO minimum of 7.3, and far below the 250 mg per kg limit AAFCO used before 2007. It is also lower than the 23.4 mg per kg diet linked to elevated liver copper in one of the studies the researchers cite.

Two things help keep our number moderate. First, because our food is plant-based, it contains no organ meats or liver, the single most copper-dense ingredients in many high-meat diets. Second, we formulate to meet the requirement rather than to load extra, and we lab-test every batch to confirm it. Like most complete foods, we do supplement with a bioavailable form of copper to meet the essential requirement reliably; the point is that the total amount is moderate, tested, and published, so you never have to guess.

Frequently asked questions

Is copper bad for dogs?

No, copper is an essential nutrient dogs need for healthy blood, enzymes, and coat. The concern is excess, not copper itself. Because copper is stored in the liver, too much over time can lead to copper-associated liver disease, so the goal is an appropriate, not excessive, amount.

How much copper should be in dog food?

AAFCO sets a minimum of 7.3 mg per kg (dry matter) for adult maintenance and currently sets no maximum, though it used a 250 mg per kg ceiling before 2007. Many veterinarians would like a modern upper limit restored. Ask your food maker for the tested copper value and compare it to these figures.

What foods are high in copper for dogs?

Organ meats, especially liver, are the most copper-dense ingredients, along with some fish. Certain plant foods, including some legumes and sweet potatoes, contribute copper as well. Diets built heavily on organ meats tend to be highest, which is one reason to check the tested number rather than guess from the label.

Which dog breeds are prone to copper storage disease?

The Bedlington Terrier has a well-known inherited copper disorder. Others that may be predisposed include the Doberman Pinscher, West Highland White Terrier, American Cocker Spaniel, and Labrador Retriever. If you have an at-risk breed, talk with your veterinarian about monitoring copper intake and liver health.

How do I find out how much copper is in my dog's food?

Copper is not on the standard label, but reputable companies publish a full nutrient analysis online or provide it on request. Look for copper in mg per kg (ppm) on a dry-matter basis and compare it to the AAFCO minimum of 7.3 and the former 250 ceiling. Petaluma publishes copper for every recipe on its product pages.

References

1. Center SA, Richter KP, Twedt DC, Wakshlag JJ, Watson PJ, Webster CRL. Is it time to reconsider current guidelines for copper content in commercial dog foods? Journal of the American Veterinary Medical Association. 2021;258(4):357-364. avmajournals.avma.org
2. Case LP. Considering Copper. The Science Dog. 2021. thesciencedog.com
3. Significantly higher hepatic copper concentrations in dogs compared to coyotes implicate excessive copper in most commercial dog foods. 2025. pubmed.ncbi.nlm.nih.gov