Iams vs Purina ONE: Which Dog Food Is Better?

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With so many dog food brands claiming to be “the best,” it’s no wonder pet parents feel overwhelmed. Today, we’re comparing two big names in the dog food aisle: Iams vs Purina ONE.

They’re both long-standing, science-backed brands with solid reputations, but which one is better for your dog’s unique needs? Find out in our head-to-head comparison.

Best For Puppies	Best For Adults	Best For Seniors
Iams Puppy	Purina ONE	Iams Mature Adult
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Brand History

Whether they’ve been around for decades or just a few years, their ethos, values, and track record speak volumes about the quality of their food. If they have a large fan base and appear popular, it’s because they are doing things right. So, let’s take a good look at their origins.

Iams: Founded On Canine Nutrition

• Parent Company: Mars, Inc.
• Formulas backed by: Decades of nutritional research
• Known for: Budget-friendly, vet-trusted dry kibble

Created in 1946 by animal nutritionist Paul Iams, this brand was built on science. His formulas were some of the first to take canine-specific dietary needs seriously. Paul Iams was so successful in his venture that he went on to create the Eukanuba brand, too.

Iams has changed hands many times during its lifetime, but is currently owned by Mars, Inc. Despite the change of owner, the brand ethos has remained, and they continue to create great value for well-balanced food available the world over.

Purina ONE: The Natural Line From A Giant Brand

• Parent Company: Nestlé
• Known for: Innovation, wide variety, strong vet partnerships
• Bonus: The first Purina line to promote real meat as the #1 ingredient

Purina has been around since the late 1800s and helped invent the dry kibble format we know today. Purina ONE is their more “natural” product line, introduced to meet modern pet owner demands.

Purina ONE is one of many product lines in the Purina brand, and this sub-brand was the first all-natural dog food. It’s one of Purina’s budget-friendly lines.

Recalls

A pet food company’s history of recalls is associated with its food safety record. It paints a picture of how seriously they take their responsibility as a food producer and how safe it is for our beloved fur babies.

The U.S. Food & Drug Administration (FDA) regulates food recalls, keeping a record of when they happen and investigating if animals were harmed. Neither Iams nor Purina ONE has a scandal-heavy past, but here’s what’s worth knowing:

Iams

Iams is a massive global company that has few large-scale recalls. There are only four dog food recalls in its history, and none in the last 10 years, according to our sources. All recalls were voluntary by the company.

• August 2013 – Dry food (potential salmonella contamination)
• March 2013 – Shakeables dog treats (mold risk)
• December 2011 – Puppy food (higher than acceptable aflatoxin levels)
• June, July, August 2010 – Cat food (potential salmonella and low levels of thiamine)
• March 2007 – varieties of Iams dog foods and cat foods (potential melamine contamination)

Purina ONE

While Purina ONE has only had one dog food recall in the sub-brand’s history (4 total dog food recalls for the parent brand), it’s still important to look at the overall brand’s recall history, which has had several isolated issues over the last decade or so. It’s important to note that each of these recalls was voluntary.

• February/March 2023 – Purina Pro Plan Veterinary Diets dry dog food (elevated vitamin D levels)
• December 2022 – Purina Pro Plan Veterinary Diets wet dog food (mislabeled product)
• July 2021 – Purina Pro Plan wet cat food (may contain plastic pieces)
• March 2016 – Pro Plan wet dog food (inadequate vitamin/mineral levels)
• August 2013 – Purina ONE dry dog food (potential salmonella)
• May 2012 – Purina Veterinary Diets canned cat food (possible low thiamine)
• July 2011 – Purina ONE dry cat food (potential salmonella)
• June 2011 – Purina dry cat food (potential salmonella)

Food Ingredient Breakdown

Both brands balance cost with quality, but there are some clear differences in approach.

Iams: Reliable But Limited

​Iams is popular, not only because they offer quality food, but also because they do so at a reasonable price. But how does this reflect in their ingredient lists?

• Often uses real meat as the first ingredient
• Relies heavily on chicken, with several lamb blends (still include chicken)
• Uses chicken by-product meal without specifying content (could be organs or less-desirable parts)
• Includes omega-6s (like chicken fat, flaxseed), but lacks omega-3-rich sources like fish oil
• Grain-inclusive only — no grain-free recipes
• Formulas targeting specific health needs, such as weight management or sensitive stomachs
• Avoids artificial flavors/preservatives
• Many formulas contain corn and soy
• Uses caramel coloring, which is unnecessary and offers no health benefit

Purina ONE: More Variety, Vet-Recommended Brand

This is mainly a grain-inclusive brand; however, they also offer a handful of grain-free options. This is a bonus compared to Iams because it caters to a broader set of canine needs.

• Real meat is always the first ingredient
• Broader protein options: chicken, beef, lamb, salmon, duck, turkey
• Includes both grain-inclusive and grain-free lines
• Also uses chicken by-product meal
• Adds in “liver flavor” and caramel color in some recipes
• Offers specialized formulas for sensitive stomachs, joints, and more
• Many formulas contain wheat, corn, and soy

Both are highly rated brands. And many dogs do well on these recipes, so the lower quality ingredients aren’t an issue for many canines.

Range Of Formulas

A dog’s three different life stages have varying nutritional requirements. So, if brands want to reach the entire doggy community, they should cater to them all with a wide range of formulas.

Dogs need different nutrition based on age, size, and health. The best brands offer formulas to match:

• Life Stage Needs: Puppy, adult, and senior blends support growth, maintenance, and aging, specifically tailored to each life stage.
• Breed Size Options: Small and large breed recipes cater to unique size-specific needs like kibble size, calorie content, nutritional concerns, joint support, and more.
• Special Diets: Options for sensitive stomachs, food allergies, joint issues, and weight control help address common health concerns.

So, how do Iams and Purina ONE measure up when it comes to variety?

IAMS offers 17 dry and 9 wet dog food formulas, while Purina Pro carries 19 dry dog food formulas and 23 wet dog food formulas. Both have options for different life stages, breed sizes, and health needs. To see which brand is best for your pup, I’ve broken the comparisons down into life stages.

Puppy Formulas Comparison

The most important life stage in any dog’s life is the initial life stage known as puppyhood. This usually lasts up until 12 to 18 months of age, depending on the breed. Many argue that this is the most important life stage because it sets the foundations for a healthy body and life.

Puppies need extra protein because it provides growing power, and additional omega fatty acids assist with brain and eye development.

Iams

Iams provides a modest but well-targeted selection of formulas designed to meet the developmental needs of puppies based on breed size.

• 3 grain-inclusive dry puppy formulas:
  • Original
  • Small/Toy Breed
  • Large Breed
• All recipes are chicken-based
• No grain-free or alternative protein options

Purina ONE

Purina ONE’s puppy line is more limited in variety but still covers the basics for growing dogs with a focus on balanced nutrition.

• 3 grain-inclusive puppy formulas:
  • General formula (chicken)
  • Large Breed (chicken)
  • True Instinct High Protein (chicken, duck, beef fat, and beef bone broth)
• No small breed-specific option
• No grain-free option

Puppy Formula Top Pick: Iams Proactive Health Puppy Review

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Iams Proactive Health Puppy is a budget-friendly formula designed to support healthy growth during your pup’s most important life stage. It’s made with real meat as the first ingredient and offers breed-size-specific versions for small/toy and large breed puppies.

Key Features

• Formulated to support the nutritional needs of growing puppies
• Made with real meat as the first ingredient
• Premium-sourced proteins
• Fortified with DHA for brain and vision development
• Added calcium for strong bones and teeth
• Supports immune health with antioxidants

Price

• $26.97 (15-lb bag)

Adult Formulas Comparison

Adulthood is the next life stage that typically lasts between one and seven years. By one year old, dogs have completed most of their growth. This means they need less protein and fat and more of a well-balanced diet. How do these two brands compare?

Iams

Iams caters to common adult dog needs with formulas based on breed size, basic protein preferences, and several health concerns. All formulas are grain-inclusive and include chicken, even in their lamb and beef recipes. That’s unfortunate for dogs with chicken sensitivities.

Iams currently offers 12 adult dry food recipes:

• Regular
• Small and large breed options
• Minichunks (for dogs that prefer smaller kibble)
• Healthy weight
• Advanced Health line
  • Healthy digestion
  • Mobility
  • Skin & coat

Purina ONE

Purina ONE covers more ground with a broader range of 16 adult dog formulas, including options for specific health needs and alternative proteins. Their protein variety is better, including chicken, lamb, beef, salmon, turkey, venison, and duck.

• One grain-free option
• Small Breed and Large Breed options
• High-protein True Instinct line
• Health-focused formulas:
  • Skin & coat
  • Joint health
  • Digestive health
  • Healthy weight

Adult Formula Top Pick: Purina ONE Adult Formula Review

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Purina ONE Adult Dog Food is a well-rounded, mid-tier kibble designed to meet the everyday nutritional needs of adult dogs. Known for its real meat-first approach, this formula balances affordability with ingredient quality, making it a popular pick for pet parents.

Key Features

• Real meat is always the first ingredient (e.g., chicken, lamb, beef)
• Available in grain-inclusive and grain-free options
• Specialized formulas for sensitive skin, joint support, and healthy weight
• Blended with omega-6 fatty acids for skin and coat health
• Antioxidant-rich to support immune health

Price

• $30.28 (16.5-lb bag)

Senior Formulas Comparison

Finally, the last stage of a dog’s life is the senior stage. Like us humans, seniors become less active, and their digestive system slows, so they need much less fuel, easier-to-digest formulas, and more glucosamine for their joints.

For all these reasons and more, it’s crucial to switch your pup’s diet to a senior kibble when the time is right. So, let’s see how these brands compare in the final life stage.

Iams

Iams supports senior dogs with two dry formulas adjusted for aging bodies, including one specifically for large breeds.

• 2 grain-inclusive senior recipes (regular and large breed)
• All are chicken-based
• L-carnitine improves a slowing metabolism
• No grain-free or alternative protein options

Purina ONE

Purina ONE keeps things simple with just one dry senior formula designed for general use across all breeds.

• Only one recipe available (no small or large breed options)
• Grain-inclusive and chicken-based
• No grain-free or alternative protein options

Senior Formula Top Pick: Iams Proactive Health Healthy Aging Review

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Iams Proactive Health Healthy Aging is a dry food formula designed specifically for senior dogs aged 7 and up. It focuses on supporting joint health, digestion, and immune strength to help older pups stay active and alert in their golden years.

Key Features

• Formulated to support the nutritional and wellness needs of senior dogs
• Real farm-raised meat as the first ingredient
• Key nutrients to support bone and joint health
• Antioxidants for immune system support
• Wholesome blend of prebiotics and fibers

Price

• $41.99 (29.1-lb bag)

Canned Foods Comparison

It’s also important for brands to offer wet food options. Although dried kibble should be the first preference, some dogs need a splash of wet food in addition to their kibble pieces.

This could be because they are fussy pups and prefer juicer meat, or they might have trouble chewing hard kibble on their own. Whatever your dog’s reason, let’s take a look at what Iams and Purina ONE offer in terms of canned food.

Iams

Iams sticks with a small, straightforward line of canned foods focused mostly on pâtés for each life stage.

• 9 total canned recipes
  • 7 adult formulas
  • 1 puppy formula
  • 1 senior formula
• All but 1 are pâtés (1 adult formula is beef chunks in gravy)
• All are grain-inclusive
• Protein options are chicken, beef, and lamb

Purina ONE

Purina ONE delivers a much larger wet food selection of 22 formulas, offering both variety in texture and grain-free alternatives.

• Several True Instinct high-protein wet formulas
• Multiple grain-free options
• 1 puppy formula
• 1 senior formula
• Variety of pâtés and tender cuts in gravy
• Variety of proteins: chicken, beef, turkey, lamb, salmon, duck, and venison

Canned Food Top Pick: Purina ONE Adult Classic Ground Canned Review

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Purina ONE Classic Ground offers a soft, meaty texture that’s ideal for adult dogs who prefer wet food or need a little help due to dental issues or picky appetites. This line focuses on complete nutrition in a savory, pâté-style meal.

Key Features

• Comes in a variety of flavors and blends
• Available for dogs in all stages of life
• Made with real meat and natural ingredients
• Contains antioxidants and vitamins
• Great for mixing with dry kibble or serving as a standalone meal
• Budget-friendly option with wide availability

Price

• $23.76 (pack of 12x 13-oz cans)

What’s My Final Verdict?

Overall, you can see that Iams and Purina ONE are very similar, which is why so many owners have trouble choosing between the two brands. I give the final nod to Purina ONE for offering a better variety overall. Ultimately, they are both highly rated brands that create complete and balanced nutrition for our pups at a budget-friendly price.

With that said, their ingredients aren’t comparable to those you can find with many premium brands, such as Orijen, Open Farm, and Diamond Naturals (a great premium budget pick).

What’s missing? Natural fruits and vegetables, probiotics, fish oil, and other superfoods. Premium brands also don’t use fillers, meat by-products, corn, wheat, or soy.

Going Beyond Kibble & Canned Food

Many dog owners are turning to fresh dog food, air-dried dog food, and even custom subscription plans for added nutrition, flavor, and convenience. We’ve reviewed and tested brands like The Farmer’s Dog, Ollie, Spot & Tango, and Badlands Ranch to give you some fantastic alternative diets.