21st Century Calcium 1000 +D
Brand: 21st Century · Form: SUPPLEMENT FORM, OTHER [E0172]
Our assessment
The evidence shows that this product combines 1000 mg of calcium with vitamin D, a pairing designed to support bone health. For most adults, the total daily calcium intake from food and supplements should be 1000 mg to 1200 mg, so this single tablet provides a significant portion of that goal [NIH ODS]. However, you should carefully account for calcium from your diet and any other supplements you take to avoid exceeding safe limits.
How it works
Think of calcium as a building block for your skeleton. It is essential for bone mineralization—the process that deposits calcium into your bones to keep them dense and strong [NIH ODS]. Calcium also plays a vital role in neuromuscular relaxation, helping your muscles relax properly and supporting healthy nerve signaling throughout your body [NIH ODS].
Safety profile
Data not available for specific side effect counts per supplement. FDA received a total of 592,059 adverse event reports across all supplements [FDA data]. It is critical to know that high calcium intakes might increase the risk of heart disease and prostate cancer [NIH ODS]. Very high blood levels of calcium can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent urination, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS].
Our recommendation
Start by reviewing your daily calcium intake from food—dairy, leafy greens, and fortified foods are common sources. If you are consistently falling short of 1000 mg daily, this supplement can help fill the gap. Take it with food to enhance absorption. Be aware that calcium can reduce the absorption of medications like bisphosphonates, tetracycline and fluoroquinolone antibiotics, levothyroxine, and phenytoin, so separate your doses by at least two hours [NIH ODS]. If you have a history of kidney stones or heart conditions, consult your doctor before starting this supplement.
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 90.0 Coated Caplet(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