Kirkland Signature Active Vitamin Pack

Our assessment

The evidence shows that the Kirkland Signature Active Vitamin Pack contains calcium, a mineral essential for bone health. However, you need to be aware that high calcium intakes might increase the risk of heart disease and prostate cancer [NIH ODS].

How it works

Think of calcium as a structural building block for your bones. It supports bone density and mineral deposition, and it also plays a role in muscle relaxation and nerve signaling [NIH ODS].

Safety profile

FDA received 592,059 total adverse event reports across all supplements. For calcium specifically, high levels in the blood and urine can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS] [FDA data].

Our recommendation

Be mindful of your total calcium intake from all sources. Calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. Data not available on the specific dosage of calcium in this product.

Supplement labels contain several key sections regulated by the FDA:

• Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
• Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
• % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
• Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
• Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.

Source: FDA Dietary Supplement Labeling Guide