Kirkland Signature KirSublingual B-12 5000 MCG supplement bottle
Kirkland Signature

KirSublingual B-12 5000 MCG Review

What We Researched
1 active ingredient analyzed · 9 inactive ingredients decoded · 4 brand certifications checked · Last updated: Aug 2026
93
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
Methylcobalamin 5000 MCG —
Bioavailability Excellent

Absorption Rating

  • Methylcobalamin Good
Other Ingredients Excellent

Fillers & Additives

  • Mannitol
  • Microcrystaline Cellulose
  • Crospovidone
  • Stearic Acid
  • Magnesium Stearate
  • Natural Cherry Flavor
  • Red Beet Root (color)
  • Silica
  • Sucralose
Efficacy Very Good

Dosage Analysis

  • Methylcobalamin 5000 MCG High

Supplement Facts

Ingredient Amount % Daily Value
Methylcobalamin 5000 MCG

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Mannitol Generally_safe

It is used as a sweetener, filler, and flow agent.

Microcrystaline Cellulose Unknown
Crospovidone Generally_safe

It is used as a binder to help tablets or capsules disintegrate.

Stearic Acid Safe

Helps ingredients flow smoothly through manufacturing equipment.

Magnesium Stearate Safe

Prevents ingredients from sticking to manufacturing equipment during tableting.

Natural Cherry Flavor Safe

It provides a cherry flavor to the product.

Red Beet Root (color) Unknown
Silica Safe

Prevents ingredients from clumping and improves powder flow.

Sucralose Generally_safe

Adds sweetness to chewables, gummies, and powdered supplements without calories.

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 KirSublingual B-12 5000 MCG a good supplement?

Kirkland Signature KirSublingual B-12 5000 MCG received a product quality score of 93/100 in GoodSupp's independent analysis, placing it in the top tier of supplements we've analyzed. The product contains 1 active ingredients Of the 9 inactive ingredients, 4 are rated safe and 0 are flagged for review. 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 KirSublingual B-12 5000 MCG?

Kirkland Signature KirSublingual B-12 5000 MCG contains 1 active ingredients: Methylcobalamin (5000 MCG). Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is Kirkland Signature KirSublingual B-12 5000 MCG safe to take?

Kirkland Signature KirSublingual B-12 5000 MCG has been analyzed for ingredient safety across all its components. 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.

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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.