Kirkland Signature infant formula is a solid, safe choice that meets the same federal nutritional standards as every name-brand formula on the shelf. At roughly 76 cents per ounce compared to $1.30 or more for brands like Similac, it delivers comparable nutrition at nearly half the price. For most healthy, full-term infants, it performs the same job as its more expensive counterparts.
Who Actually Makes Kirkland Formula
Kirkland Signature formula isn’t made by Costco. It’s manufactured by Perrigo, the world’s largest store-brand producer of over-the-counter pharmaceutical products and infant formulas. Perrigo also makes formula sold under other major store brands at retailers like Walmart, Target, and Walgreens. This matters because it means your Kirkland formula comes off the same production lines, using the same processes, as dozens of other widely sold formulas.
Perrigo has been supplying Kirkland formula to Costco since at least 2011, when the company expanded distribution into Canadian stores. The long-standing relationship reflects a level of manufacturing consistency that newer or smaller brands can’t always match.
Nutritional Quality Compared to Name Brands
The FDA requires all infant formulas sold in the United States to contain 30 specific nutrients at levels that support healthy growth. This applies equally to a $40 tub of Similac and a $20 tub of Kirkland. Every formula on store shelves, whether domestic or imported, must meet the same safety and nutritional adequacy requirements before it can be sold. New formulas also undergo FDA review to confirm they contain adequate protein and support normal infant development.
Kirkland Signature ProCare, the brand’s main offering, includes DHA and ARA, two fatty acids naturally found in breast milk that support brain development. It also contains lutein, an antioxidant that plays a role in eye development. These are the same ingredients highlighted on the front labels of Enfamil and Similac products, often at premium prices. The core nutritional profile is functionally the same because the FDA’s nutrient floors and ceilings leave relatively little room for meaningful variation between brands.
Where name brands sometimes differ is in specialized formulas for reflux, milk protein allergies, or premature infants. Kirkland’s lineup is narrower, so if your baby needs a highly specialized formula, you may not find it under the Kirkland label. For standard feeding of healthy infants, though, the nutrition is equivalent.
How Much You’ll Save
The price difference is the main reason parents consider Kirkland formula, and the savings are substantial. Consumer Reports found Kirkland Signature ProCare costs about 76 cents per ounce. Similac Advance runs $1.38 per ounce, and Pure Bliss by Similac costs $1.30 per ounce. That’s roughly 45 to 55 percent more for the name brand.
To put that in real terms: a baby who drinks about 25 ounces of formula per day will go through roughly $19 worth of Kirkland formula per day versus $34.50 of Similac. Over a year, that gap adds up to thousands of dollars. Since you need a Costco membership to buy it, factor in the $65 annual fee, but it pays for itself within the first few weeks of formula feeding.
The 2019 Recall
Kirkland formula has had one notable safety event. In October 2019, Costco recalled specific lots of Kirkland Signature Non-GMO Infant Formula for Babies Sensitive to Lactose due to possible contamination with Cronobacter, a bacterium that can be dangerous for newborns. The recall was limited to products with an expiration date of November 2020 and specific lot codes. No illnesses were reported in connection with the recall.
It’s worth noting that Walmart recalled its Parent’s Choice formula at the same time for the same reason, and both products were manufactured by Perrigo. Recalls happen across the entire formula industry, including to Similac (which had a massive recall in 2022 affecting millions of containers). A single, contained recall doesn’t indicate a pattern of poor quality, but it’s a fair data point for parents researching the brand.
Where Kirkland Formula Falls Short
The biggest limitation is variety. Major brands like Enfamil and Similac offer extensive product lines: formulas thickened for reflux, extensively hydrolyzed options for cow’s milk protein allergy, amino acid-based formulas for severe allergies, and formulas designed specifically for premature infants. Kirkland offers a handful of standard formulas. If your pediatrician recommends a specialized formula, Kirkland probably won’t have it.
Availability can also be an issue. You can only buy Kirkland formula at Costco or on Costco’s website. If you run out at 10 p.m. on a Sunday, you can’t pick it up at a corner store. Some parents keep a small supply of a name brand as a backup for exactly this situation, which works fine since switching between nutritionally equivalent formulas doesn’t cause problems for most babies.
Finally, some babies are simply picky. Two formulas can have nearly identical ingredient lists but taste slightly different due to fat blends or protein processing. If your baby refuses Kirkland after a fair trial of several days, that’s a valid reason to switch, but it has nothing to do with quality.
Switching From a Name Brand
If your baby is currently on Similac or Enfamil and you want to try Kirkland, there’s no need for a gradual transition in most cases. Because the nutritional profiles are so similar, most babies tolerate a direct switch without digestive issues. Some parents prefer to mix the old and new formulas in gradually increasing ratios over a few days, and that approach is fine too.
Watch for signs your baby isn’t tolerating the new formula: excessive gas, unusual fussiness, constipation, diarrhea, or rashes that appear within a week of switching. These reactions are uncommon when moving between standard milk-based formulas, but every baby’s digestive system is different. Give the switch at least a full week before deciding it isn’t working, since minor changes in stool consistency or gas are normal and usually resolve on their own.