21st Century Cal Mag Zinc +D
Brand: 21st Century · Form: TABLET [E0155]
Our assessment
The evidence shows that this combination supplement provides a foundational mineral, calcium, which supports bone health and nerve function. However, you need to be cautious with dosing, as high calcium intake carries real risks. The data we have is specific to calcium, while data for the other ingredients (magnesium, zinc, and vitamin D) in this product is not available in our provided sources.
How it works
Think of calcium as a structural builder and signal messenger. It supports bone mineralization, helping deposit minerals into your skeleton for density, and it plays a role in neuromuscular relaxation, which allows your muscles to relax and your nerves to signal properly [NIH ODS].
Safety profile
FDA has received a total of 592,059 adverse event reports across all supplement categories. For calcium specifically, safety concerns include that high intakes might increase the risk of heart disease and prostate cancer. Very high levels of calcium 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].
Our recommendation
Before starting this supplement, check your total calcium intake from food and other supplements to avoid exceeding safe levels. Be aware that calcium can reduce the absorption of medications like bisphosphonates, tetracycline and fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. Data on the exact dosage of calcium, magnesium, zinc, and vitamin D in this specific product is listed as "See label" — you must read the label to determine if the dose is appropriate for you. Data not available for the specific benefits and risks of the magnesium, zinc, and vitamin D components.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 90.0 Tablet(s) |
| Market Status | Off Market |
How to Read This Label
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