21st Century Calcium 500
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that calcium is essential for bone health, but the specific product "21st Century Calcium 500" requires careful consideration. Our assessment is that while calcium supplementation is well-supported, you need to be aware of the potential risks associated with high intake and the specific dose of this supplement [NIH ODS].
How it works
Think of calcium as a structural building block for your skeleton. It works by supporting bone mineralization, which means it helps deposit minerals into your bone matrix to maintain density. Additionally, calcium plays a role in neuromuscular relaxation, helping your muscles relax and your nerves signal properly after they fire [NIH ODS].
Safety profile
FDA received 592059 total adverse event reports for products containing this ingredient. You should be aware 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]. Calcium can also reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
We recommend you start by assessing your total daily calcium intake from food and other supplements. The dose in this product is 500 mg, which is a common supplement amount. To minimize risks, do not exceed the tolerable upper intake level from all sources combined. If you take any of the listed medications, separate your calcium dose by at least two hours to avoid absorption issues [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