21st Century Calcium 500+D3 plus Extra D3
Brand: 21st Century · Form: TABLET [E0155] On Market
Our assessment
The evidence shows that calcium, the primary active ingredient in 21st Century Calcium 500+D3 plus Extra D3, is a well-established mineral for bone health. However, the data also indicates important safety considerations you should be aware of before starting this supplement. The FDA has received a total of 592,059 adverse event reports for products containing these ingredients, which underscores the need for careful use [FDA data].
How it works
Think of calcium as a key building block for your body. It works primarily through bone mineralization, helping to support bone density and mineral deposition. It also plays a critical role in neuromuscular relaxation, supporting both muscle relaxation and nerve signaling throughout your body [NIH ODS].
Safety profile
The safety data reveals several important risks. 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]. Additionally, calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS].
Our recommendation
For you, we recommend starting with a careful review of your total calcium intake from both food and supplements. Because of the potential for serious side effects and medication interactions, it is essential to consult your healthcare provider before use, especially if you take any prescription medications. Data not available on the specific dose per serving for this product, so check the label carefully [NIH ODS].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 200.0 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