“Signature dog foods” usually means two unrelated brands: Kirkland Signature, Costco’s store brand, and Zignature, a limited-ingredient, grain-free brand. They share only a word in their names. Kirkland is a low-cost everyday food for most healthy dogs, while Zignature is a pricier single-protein food that is often used for dogs with suspected food sensitivities.
Kirkland Signature
Kirkland Signature is sold at Costco in large bags and cans. Its dry foods have historically been made by Diamond Pet Foods, though Costco can change its suppliers, so check the bag. Costco sells formulas for adult dogs, puppies, small breeds and large breeds, plus grain-free and cans.
- Pros: Low price per pound, real meat first in most recipes and easy returns at Costco.
- Cons: Available only to Costco members, and some recipes use peas and legumes that raise questions about grain-free diets.
For the wet line, see our Kirkland canned dog food review.
Zignature
Zignature makes limited-ingredient recipes built around a single animal protein such as salmon, turkey or lamb. The recipes are grain-free and avoid common allergens such as chicken, corn, wheat and soy. They are marketed to dogs with sensitive stomachs or suspected food allergies.
- Pros: A short ingredient list and unusual proteins can be useful for elimination diets.
- Cons: More expensive than store brands, and grain-free recipes with legumes have appeared in FDA reports looking at diet-associated heart disease (DCM). Ask your vet whether a grain-free diet is right for your dog.
How to Choose Between Them
- Pick Kirkland if you want a good-value, complete food for a healthy dog and you shop at Costco.
- Pick a limited-ingredient food such as Zignature if your vet suggests an elimination diet for allergies.
- Look at the first five ingredients, the AAFCO statement and the recall history of the company that makes it.
For other options, see our list of dog foods without corn, wheat or soy.
Switching Foods
- Change foods over 7 to 10 days.
- Weigh your dog every few weeks to adjust portions.
- Give a new food several weeks before judging skin or coat changes.
This is general information, not veterinary advice. Talk to your vet about food allergies and the best diet for your dog.
Bottom Line
Kirkland Signature is the budget pick for healthy dogs, and Zignature is a limited-ingredient option for dogs with suspected sensitivities. Check labels, recall history and the grain-free question with your vet before you switch.
