Kirkland Signature Magnesium Citrate 250 mg supplement bottle
Kirkland Signature

Magnesium Citrate 250 mg Review

What We Researched
2 active ingredients analyzed · 7 inactive ingredients decoded · 4 brand certifications checked · Last updated: Aug 2026
100
Product Score Excellent
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
Magnesium Citrate 250 mg
Magnesium 250 mg
Bioavailability Excellent

Absorption Rating

  • Magnesium Citrate Good
  • Magnesium Good
Other Ingredients Excellent

Fillers & Additives

  • Medium Chain Triglycerides
  • Bovine Gelatin
  • Yellow Beeswax
  • Glycerin
  • Annatto
  • Purified Water
  • Soy Lecithin
Efficacy Excellent

Dosage Analysis

  • Magnesium Citrate 250 mg Effective
  • Magnesium 250 mg Effective

Supplement Facts

Ingredient Amount % Daily Value
Magnesium Citrate 250 mg
Magnesium 250 mg

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Medium Chain Triglycerides Safe

Enhances absorption of fat-soluble vitamins.

Bovine Gelatin Safe

Forms capsule shells. Sourced from bovine (cow) collagen.

Yellow Beeswax Safe

Helps form and seal softgel capsules.

Glycerin Safe

Retains moisture and helps dissolve ingredients in softgels and liquids.

Annatto Safe

Provides natural color to supplements.

Purified Water Safe

Dissolves and carries water-soluble ingredients.

Soy Lecithin Safe

Helps blend oil and water-based ingredients. Common allergen.

Brand Trust Report
Kirkland Signature

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

Certifications

4 certifications
Usp Verified Verified Source
Informed Choice Verified
USDA Organic Verified
Gluten-Free Certified Verified

Transparency

5 claims
Third Party Testing Claim — Verified Source
Testing Lab Disclosure — Claimed
In House Testing — Claimed
Contains Proprietary Blend — True

Violation History

3 incidents
Lawsuit Falsely advertising rotisserie chicken as containing 'no preservatives'2026Source
Recall Kirkland Signature B100 Complex Timed Release2025-03-31Source
Recall Kirkland Signature Severe Cold and Flu Plus Congestion2024-11-30Source
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Frequently Asked Questions
Is Kirkland Signature Magnesium Citrate 250 mg a good supplement?

Kirkland Signature Magnesium Citrate 250 mg received a product quality score of 100/100 in GoodSupp's independent analysis, placing it in the top tier of supplements we've analyzed. The product contains 2 active ingredients with 135 servings per container. All 7 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 with 4 verified certifications including Usp Verified, Informed Choice, USDA Organic, Gluten-Free Certified.

What are the ingredients in Kirkland Signature Magnesium Citrate 250 mg?

Kirkland Signature Magnesium Citrate 250 mg contains 2 active ingredients: Magnesium Citrate (250 mg), Magnesium (250 mg). Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is Kirkland Signature Magnesium Citrate 250 mg safe to take?

Kirkland Signature Magnesium Citrate 250 mg has been analyzed for ingredient safety across all its components. All 7 inactive ingredients — including capsule materials, fillers, and binders — are rated safe based on regulatory data and published safety research. This is a clean formulation with no controversial additives. 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. They hold 4 verified certifications including Usp Verified, Informed Choice, USDA Organic, Gluten-Free Certified. Third-party certifications are independently verified and indicate the brand meets specific quality, purity, and manufacturing standards. 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.