Kirkland Signature Calcium Citrate Magnesium and Zinc with D3 supplement bottle
Kirkland Signature

Calcium Citrate Magnesium and Zinc with D3 Review

What We Researched
8 active ingredients analyzed · 4 inactive ingredients decoded · 4 brand certifications checked · Page generated: Sep 2026
84
Product Score Good
80
Brand Score Good

Two independent scores — the product and the brand behind it, never blended into one number. See our methodology.

Product Analysis

Transparency Excellent

Supplement Facts

IngredientAmount% DV
Vitamin D3 20 mcg —
Copper 1 mg —
Zinc 10 mg —
Boron 1 mg —
Vitamin B6 10 mg —
Calcium 500 mg —
Magnesium 80 mg —
Manganese 1 mg —
Bioavailability Very Good

Absorption Rating

  • Vitamin D3 Good
  • Copper Fair
  • Zinc Fair
  • Boron Fair
  • Vitamin B6 Fair
  • Calcium Good
  • Magnesium Good
  • Manganese Good
Other Ingredients Excellent

Fillers & Additives

  • Cellulose
  • Croscarmellose Sodium
  • Magnesium Stearate
  • Silicon Dioxide
Efficacy Good

Dosage Analysis

  • Vitamin D3 20 mcg Effective
  • Copper 1 mg Effective
  • Zinc 10 mg Effective
  • Boron 1 mg Under-dosed
  • Vitamin B6 10 mg Effective
  • Calcium 500 mg Effective
  • Magnesium 80 mg Under-dosed
  • Manganese 1 mg Under-dosed

Supplement Facts

Ingredient Amount % Daily Value
Vitamin D3 20 mcg
Copper 1 mg
Zinc 10 mg
Boron 1 mg
Vitamin B6 10 mg
Calcium 500 mg
Magnesium 80 mg
Manganese 1 mg

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Cellulose Safe

Provides bulk and structure in tablets and capsules.

Croscarmellose Sodium Safe

Helps tablets break apart and dissolve quickly in the stomach.

Magnesium Stearate Safe

Prevents ingredients from sticking to manufacturing equipment during tableting.

Silicon Dioxide Safe

Prevents clumping and ensures consistent dosing.

Brand Trust Report
Kirkland Signature

Founded 1995 · Issaquah, Washington, United States · 56 products · costco.com/kirkland-signature.html

Certifications

4 certifications
Usp Verified Source available Primary evidence
Informed Choice Supporting evidence unavailable
USDA Organic Supporting evidence unavailable
Gluten-Free Certified Supporting evidence unavailable

Transparency

5 claims
Third Party Testing Claim — Verified Evidence available Evidence
Testing Lab Disclosure — Claimed Brand claim; evidence unavailable
In House Testing — Claimed Brand claim; evidence unavailable
Contains Proprietary Blend — True Brand claim; evidence unavailable

Violation History

3 incidents
Lawsuit Falsely advertising rotisserie chicken as containing 'no preservatives'2026 Source available Primary source
Recall Kirkland Signature B100 Complex Timed Release2025-03-31 Source available Primary source
Recall Kirkland Signature Severe Cold and Flu Plus Congestion2024-11-30 Source available Primary source
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Frequently Asked Questions
Is Kirkland Signature Calcium Citrate Magnesium and Zinc with D3 a good supplement?

Kirkland Signature Calcium Citrate Magnesium and Zinc with D3 received a product quality score of 84/100 in GoodSupp's independent analysis, indicating strong overall quality. The product contains 8 active ingredients with 250 servings per container. All 4 inactive ingredients (fillers, binders, capsule materials) are rated safe — a clean formulation with no flagged additives. The manufacturer, Kirkland Signature, holds a brand trust score of 80/100.

What are the ingredients in Kirkland Signature Calcium Citrate Magnesium and Zinc with D3?

Kirkland Signature Calcium Citrate Magnesium and Zinc with D3 contains 8 active ingredients: Vitamin D3 (20 mcg), Copper (1 mg), Zinc (10 mg), Boron (1 mg), Vitamin B6 (10 mg), Calcium (500 mg), and 2 more. Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is Kirkland Signature Calcium Citrate Magnesium and Zinc with D3 safe to take?

GoodSupp reviewed the inactive-ingredient data available for Kirkland Signature Calcium Citrate Magnesium and Zinc with D3. All 4 inactive ingredients — including capsule materials, fillers, and binders — are currently classified as safe in GoodSupp's ingredient reference data. This label analysis cannot determine whether the product is safe for a particular person, and source labels may change. Always consult your healthcare provider before starting any new supplement, especially if you take medications or have underlying health conditions.

Is Kirkland Signature a trustworthy supplement brand?

Kirkland Signature receives a brand trust score of 80/100 based on GoodSupp's independent analysis of certifications, regulatory history, and transparency practices. Founded in 1995 and headquartered in Issaquah, Washington, United States, the company offers 56 products in their lineup. Note: Kirkland Signature has 3 historical regulatory incidents on record, which are factored into the trust score.

What is magnesium good for?

Magnesium Good For is a topic many supplement consumers ask about. In the context of dietary supplements, understanding magnesium good for helps you make more informed choices about what you put in your body. The quality and form of ingredients matters significantly — two products listing the same ingredient can differ dramatically in bioavailability and effectiveness. GoodSupp analyzes over 150,000 supplement products to help consumers understand exactly what's in their supplements and whether the formulation meets quality standards.

How much magnesium per day?

The optimal dosage depends on your individual health needs, age, sex, and current nutrient levels. Recommended daily amounts are established by health authorities but may vary from therapeutic doses used in clinical research. It's important to check the Supplement Facts label for the exact amount per serving and compare it against the % Daily Value. Some supplements provide mega-doses well above the Daily Value, which may not be necessary and in some cases could be harmful — particularly for fat-soluble vitamins (A, D, E, K) that accumulate in the body. GoodSupp's efficacy analysis evaluates whether a product's dosages align with clinically studied amounts. Always consult your healthcare provider for personalized dosage recommendations.

What is zinc good for?

Zinc Good For is a topic many supplement consumers ask about. In the context of dietary supplements, understanding zinc good for helps you make more informed choices about what you put in your body. The quality and form of ingredients matters significantly — two products listing the same ingredient can differ dramatically in bioavailability and effectiveness. GoodSupp analyzes over 150,000 supplement products to help consumers understand exactly what's in their supplements and whether the formulation meets quality standards.

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Disclaimer: GoodSupp provides independent supplement quality analysis for informational purposes only. Scores are generated algorithmically based on ingredient profiles, brand certifications, and public records — read our methodology. This is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Product data is sourced from manufacturer labels and public databases. GoodSupp is not affiliated with any supplement brand.