Kirkland Signature — The Infant Formula Atlas

By María López Botín · Mother of 2, researching infant formula and infant nutrition since 2018

Affiliate disclosure: this guide includes affiliate links to Organic's Best Shop (our recommended European formula importer) in related content. Kirkland Signature itself is not sold via affiliate channels.

Kirkland Signature is Costco Wholesale's private-label infant formula brand, exclusively available to Costco members. Following the standard US private-label pattern, Kirkland Signature is primarily manufactured by Perrigo at the Allegan, Michigan facility, the same FDA-registered plant that produces Walmart's Parent's Choice, Target's Up&Up, and Amazon's Mama Bear. Costco's membership retail model and bulk packaging typically results in per-ounce prices even lower than other private labels, making Kirkland particularly relevant for multi-infant households, preparation-at-scale families, and budget-focused Costco-member families.

Kirkland Signature is Costco Wholesale's private-label infant formula, primarily manufactured by Perrigo at the Allegan, Michigan facility. FDA 21 CFR 107 compliance is identical to major brands and other private labels. Bulk Costco packaging often provides lower per-ounce cost than Parent's Choice, Up&Up, or Mama Bear. Available exclusively to Costco members (in-warehouse and online). Not organic. This hub completes Atlas coverage of major US private-label infant formulas alongside Parent's Choice (Walmart), Up&Up (Target), and Mama Bear (Amazon).

Company snapshot

Attribute	Value
Retailer/brand owner	Costco Wholesale Corporation
Primary manufacturer	Perrigo Company plc
Founded	1995 (Kirkland Signature brand; infant formula launched subsequently)
Manufacturing location	Perrigo facilities, Allegan, Michigan (primary)
Product category	Standard (ProCare)
FDA registered as infant formula	Yes (21 CFR 107)
Membership required	Yes (Costco Wholesale membership)
Sold by Organic's Best Shop	No
Typical price vs Similac/Enfamil	40-50% lower

The US private-label complete picture

With Kirkland Signature documented, the Atlas now covers all four major US private-label infant formula brands:

Retailer	Private-label brand	Primary manufacturer
Walmart	Parent's Choice	Perrigo
Target	Up&Up	Perrigo
Amazon	Mama Bear	Perrigo
Costco	Kirkland Signature (this brand)	Perrigo

All four share fundamental characteristics:

Manufactured at Perrigo's Allegan, Michigan facility
FDA 21 CFR 107 compliant
Substantially cheaper than major brands (Similac, Enfamil)
Retailer-exclusive brand names
Nutritionally equivalent to major brands (FDA-regulated equivalence)

Differences between the four are primarily:

Retailer access, which store you shop at
Packaging and size: Costco bulk vs other retailers' single cans
Specific pricing: Costco typically lowest per-ounce
Available variants, some retailers offer more variants than others

The Costco bulk advantage

Costco's wholesale/bulk retail model creates specific Kirkland Signature advantages:

Bulk pricing

Per-ounce pricing is typically 5-15% lower than other private labels. For families consuming exclusive formula (30 oz/day for a 3-month-old), the annual savings vs major brand are substantial:

Product	Approximate annual cost (exclusive feeding)
Similac Pro-Advance	$2,900-3,850
Enfamil NeuroPro	$2,900-3,850
Parent's Choice Advantage Premium	$1,800-2,400
Up&Up Advantage Premium	$1,800-2,400
Mama Bear Advantage	$1,800-2,400
Kirkland Signature ProCare	$1,700-2,300

Membership consideration

Costco membership costs $65-130/year depending on tier. For a family consuming exclusive formula, the annual savings vs major brands typically justifies membership cost even if formula is the only Kirkland purchase.

Large package sizes

Kirkland typically sells in larger can sizes (often 34 oz vs 20-24 oz standard) and multi-can packs. Storage space consideration matters, unopened tins have standard shelf life, but bulk purchases require space.

Kirkland Signature product line

Kirkland Signature ProCare Infant Formula

Standard milk-based infant formula positioned against Similac Pro-Advance and Enfamil NeuroPro. Lactose-primary, DHA/ARA fortified, typical US premium feature set.

See the SKU record: Kirkland Signature ProCare.

Limited variant range

Unlike Parent's Choice (which offers 5 and variants) or Up&Up (which offers 4 and variants), Kirkland Signature typically has fewer variants in the infant formula category. This reflects Costco's SKU-minimization retail strategy, bulk pricing on fewer products rather than variety.

Regulatory status

Kirkland Signature is FDA-registered under 21 CFR 107 with identical compliance to major brands. Perrigo Allegan facility undergoes annual FDA inspection. See:

When Kirkland Signature makes sense

Clear fit

Costco-member families already shopping there regularly
Multi-infant households (twins, triplets, or sequential infants) benefiting from bulk
Budget-conscious families with adequate storage space
Reliable supply preference, having 4-8 weeks of formula on hand from one shop visit

Less optimal fit

Families without Costco membership, annual membership cost factors in
Small storage households, bulk cans take space
Specialty formula families: Costco doesn't carry specialty formula brands (Nutramigen, Alimentum, Neocate) extensively
Organic families: Kirkland Signature infant formula is non-organic

How Kirkland Signature compares

Against other private labels

Essentially interchangeable product specifications with Parent's Choice, Up&Up, and Mama Bear, same Perrigo manufacturer, same FDA compliance, similar formulations. Differences are primarily:

Access: Costco membership required vs open retail
Size: larger packages, bulk pricing
Brand identity: Costco member-community familiarity

Against major brands

Same FDA nutritional compliance at 40-50% lower cost. Clinically equivalent for healthy term infants. The major brand premium primarily reflects marketing, R&D overhead, and brand equity — not infant health outcomes.

Against organic alternatives

Kirkland Signature is non-organic. Families prioritizing organic need to look elsewhere:

Bobbie. US organic
Happy Baby Organic
European organic imports via Organic's Best Shop

Editorial notes from María

Kirkland Signature completes the US private-label infant formula documentation. For Costco-member families, Kirkland typically represents the lowest-cost reasonable choice, same Perrigo manufacturing quality as other private labels, with Costco's bulk pricing and membership retail model providing additional savings.

The US private-label tier (Parent's Choice, Up&Up, Mama Bear, Kirkland) is genuinely underserved in pediatric formula guidance. Most pediatric conversations focus on major brands or specialty formulas, while millions of families use private-label products that provide equivalent nutrition at substantially reduced cost.

For the typical healthy term infant of a Costco-member family, the choice between Kirkland Signature ProCare and major brands is more about brand loyalty and marketing effect than infant health outcomes. FDA nutritional equivalence is regulatory-mandated.

Kirkland Signature is not sold by Organic's Best Shop. This hub completes US private-label brand coverage in the Atlas.

For related profiles:

Parent's Choice — Walmart private label
Up&Up: Target private label
Mama Bear: Amazon private label
Similac, major brand reference
Enfamil, major brand reference

Frequently asked questions

Is Kirkland Signature ProCare made by the same company as Similac?

No. Kirkland Signature ProCare is manufactured by Perrigo, the largest US private-label infant formula manufacturer. Similac is manufactured by Abbott Nutrition. Both are FDA-registered under 21 CFR 107 and meet the same nutrient adequacy standards. Perrigo also makes Walmart's Parent's Choice, Target's Up & Up, and Amazon's Mama Bear — these private-label store brands share Perrigo's underlying formulation platform with minor branding differences.

Why is Kirkland so much cheaper than Similac or Enfamil?

Private-label economics: no consumer marketing budget, no R&D bioactive premium, Costco's bulk-purchase pricing power, and Perrigo's manufacturing scale. The cost difference doesn't reflect inferior quality — Kirkland meets the same FDA 21 CFR 107 nutrient minimums. What you give up at the lower price tier is the bioactive depth (HMOs, MFGM, premium prebiotic blends) that Similac Pro-Advance and Enfamil NeuroPro include.

Is Kirkland Signature WIC-eligible?

Generally no. WIC contracts at the state level with one major manufacturer (Abbott or Reckitt) — Kirkland's Perrigo manufacturer doesn't typically hold state WIC contracts. WIC-eligible families receive Similac, Enfamil, or Gerber depending on state. If you're WIC-eligible, your assigned brand is essentially free; Kirkland Signature is a buy-out-of-pocket option that makes financial sense only if you're not on WIC.

Is Kirkland Signature ProCare nutritionally equivalent to Similac Pro-Advance?

On basic FDA 21 CFR 107 nutrient adequacy, yes. On bioactive depth, no — Similac Pro-Advance includes 2'-FL HMO; Kirkland ProCare does not in current formulation. The clinical significance of HMO supplementation for healthy term infants is debated; growth and development outcomes are equivalent at the bioactive-free vs HMO-included tiers in published trials. Most infants thrive on either.

Can I switch between Kirkland Signature and other brands?

Yes for healthy term infants. AAP permits same-category brand switching without pediatric consultation. A 4-6 day gradual transition (25%/50%/75%/100% by feed) minimizes any GI adjustment. This is genuinely a non-event for most infants — both Kirkland and the major branded formulas use the same general protein/fat/carbohydrate composition framework.

Is Kirkland Signature only available at Costco?

Yes — Kirkland is Costco's house brand and isn't sold at other retailers in any meaningful volume. Costco membership is required for in-warehouse purchase; Costco.com online ordering is also membership-restricted. The bulk-purchase economics of Costco shopping pair well with formula stockpile pacing — typical purchase is a 2-tin or 3-tin bundle that covers 4-6 weeks of consumption for a Stage 1 infant.

Primary sources

Costco Wholesale Corporation: Kirkland Signature brand and product information. costco.com
Perrigo Company plc: Primary contract manufacturer for US private-label infant formulas. perrigo.com
FDA: Infant Formula Guidance and 21 CFR 107 regulation. fda.gov
USDA Food and Nutrition Service: WIC program and formula cost context. fns.usda.gov
AAP: HealthyChildren.org on FDA-registered infant formula nutritional equivalence. aap.org

This site provides research and comparisons, not medical advice. Consult your pediatrician before changing your baby's formula.

All Kirkland Signature formulas

Kirkland Signature ProCare