21st Century Calcium 1000 mg
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that calcium is essential for your bone health and nerve function, but the data on supplementation requires careful consideration. For the product 21st Century Calcium 1000 mg, our assessment is that while calcium is a critical mineral, you should be aware of potential risks from high intakes before starting a supplement [NIH ODS].
How it works
Think of calcium as a structural builder for your skeleton and a messenger for your muscles and nerves. It directly supports bone mineralization and density, and it helps regulate muscle relaxation and nerve signaling throughout your body [NIH ODS].
Safety profile
The FDA has received 592,059 total adverse event reports for all products, though specific numbers for this calcium product are not available. Some research suggests that high calcium intakes might increase the risk of heart disease and prostate cancer. 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] [FDA data]. You should also know that calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
Our recommendation is to first assess your total daily calcium intake from food and other supplements before adding 1000 mg. Because high intakes carry significant risks, including potential heart issues, we advise you to not exceed the tolerable upper intake level and to discuss this supplement with your doctor, especially if you take any medications that interact with calcium [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