21st Century Calcium 500+D3
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that the 21st Century Calcium 500+D3 supplement provides a standard 500 mg dose of calcium, which supports bone health. However, you need to be cautious about total calcium intake from all sources, including food and other supplements, as high intakes may pose risks [NIH ODS].
How it works
Calcium works as a mineral building block for your bones. It supports bone mineralization and density, and it also plays a role in neuromuscular relaxation and nerve signaling [NIH ODS]. Vitamin D3 is often added to help your body absorb the calcium more effectively.
Safety profile
Data not available on side effects specific to this product. However, high calcium intake can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, and abnormal heart rhythms [NIH ODS]. Some research also suggests a possible increased risk of heart disease and prostate cancer with high intakes [NIH ODS]. The FDA has received 592,059 adverse event reports related to calcium supplements in general [FDA data].
Our recommendation
Start by reviewing your total daily calcium intake from food and other supplements. If you are already getting enough calcium from your diet, this supplement may not be necessary. If you do use it, take it with food and separate it by at least 2 hours from medications like thyroid hormone or certain antibiotics, as calcium can block their absorption [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 90.0 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