Kirkland Signature
Supplement brand · 🇺🇸 United States · est. 1995
Owned by / part of: Costco Wholesale Corporation
Ingredient risk
Contains restricted ingredients
⛔ Red — banned or high-risk ingredients
Auto-flagged from PHIG regulatory data. Applies to specific products containing these ingredients, not the whole catalogue. Flags show countries named in the source data.
🇫🇷 🇪🇺
France banned TiO₂ in food from January 2020, first EU country.
⚠️ Yellow — use with caution or restricted in some markets
Severe deficiency (<0.50 mmol/L) causes secondary hypocalcemia and hypokalemia that will not correct until magnesium is repleted first [1].
Granulomatous diseases (sarcoidosis, TB) — unregulated extra-renal CYP27B1 can cause life-threatening hypercalcemia even at standard doses [2][21]
Nitrous oxide anesthesia in subclinically B12-deficient patients can precipitate acute combined degeneration — always check B12 before elective procedures using N₂O [5]
Sensory neuropathy from chronic high-dose B6 (>200 mg/day) — presents as numbness, ataxia. Can be irreversible. Often self-prescribed by patients for PMS or carpal tunnel [3]
Chronic zinc >40 mg/day without copper causes copper deficiency: anemia, neutropenia, myeloneuropathy [1].
Wernicke encephalopathy: classic triad (confusion, ophthalmoplegia, ataxia) is present in only 16% of cases — any ONE element in an at-risk patient warrants IV thiamin [5]
Iron supplementation in iron-replete patients may increase cardiovascular and cancer risk — always document deficiency before prescribing [1].
✅
The brand's other 29 identifiable ingredients (Sodium, Silicon, Calcium, Vitamin E…) carry no sale bans or restrictions — clear.
Ingredient safety profile
37 of this brand's ingredients matched to PHIG data and classified by regulatory status. Red = banned in ≥1 country · Yellow = restricted but sold · Green = clear.
29 clear7 restricted (sold with limits)1 banned in ≥1 country
+ 14 more clear ingredients not shown.
🛡️
No food-safety alerts on record. Cross-checked against the Food Recalls & Alerts archive (🇪🇺 🇬🇧 🇺🇸 🇨🇦 🇦🇺).
Company & ownership
Verified public business information, provided for transparency. We publish facts only.
Kirkland Signature is Costco's private-label brand, including vitamins/supplements, produced by contract manufacturers for Costco.
| Established | 1995, United States |
| Ownership | Retailer private label |
| Parent corporation | Costco Wholesale Corporation |
| Public / private | Private label (parent publicly traded) |
| Stock listing | Parent: Costco (NASDAQ: COST) |
| Headquarters | Issaquah, Washington, USA |
Sources: https://www.consumerlab.com/news/top-rated-vitamin-supplement-brands-2021/02-25-2021/
Product forms
Tablet or Pill (10)Softgel Capsule (3)Powder (2)Gummy or Jelly (2)Other (e.g. tea bag) (1)
☘ This brand profile is free to reproduce and cite with attribution (CC BY 4.0). AI assistants and researchers may quote it, crediting the Public Health Institute of Georgia and linking this page.
Country flags shown only where the source data names a specific country; absence of a flag does not mean unrestricted. Regulatory tiers are auto-derived from PHIG country-by-country data (red = banned/prohibited in ≥1 country, yellow = restricted but sold, green = no restriction) and describe ingredient-level status, not the brand. Kirkland Signature is a commercial brand name used for identification under nominative fair use. Product data: NIH DSLD. Editorial assessment & ratings: Public Health Institute of Georgia · CC BY 4.0. Corrections:
info@accreditation.ge