21st Century Calcium 500+D3
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that calcium is essential for bone health, but you need to be careful with dosing. Our assessment: 21st Century Calcium 500+D3 provides 500 mg of elemental calcium per serving, which is a standard dose, but you must account for your total daily intake from food and other supplements [NIH ODS].
How it works
Think of calcium as a structural builder for your skeleton. It supports bone mineralization and density, and it also plays a role in neuromuscular relaxation and nerve signaling [NIH ODS]. This means it helps your bones stay strong and your muscles function properly.
Safety profile
Data not available for this specific product. However, FDA received 592,059 total adverse event reports for calcium-containing supplements. High calcium intakes might increase the risk of heart disease and prostate cancer, and can cause constipation, nausea, weight loss, extreme tiredness, and abnormal heart rhythms [FDA data] [NIH ODS]. You should also know that calcium can reduce the absorption of medications like bisphosphonates, certain antibiotics, and levothyroxine [NIH ODS].
Our recommendation
Start by tracking your total daily calcium from food. If you need a supplement, this 500 mg dose is reasonable for most adults, but do not exceed the RDA of 1,000–1,200 mg total per day from all sources [NIH ODS]. Take it with food and separate from other medications by at least 2 hours to avoid absorption issues [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 400.0 Tablet(s) |
| Market Status | On 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