21st Century Calcium 600
Brand: 21st Century · Form: SUPPLEMENT FORM, OTHER [E0172] On Market
Our assessment
The evidence shows that 21st Century Calcium 600 is a straightforward calcium supplement designed to support bone health. Our assessment: if you are looking to meet your daily calcium needs, this product provides a standard 600 mg dose per serving. However, you must be aware of the specific risks and interactions associated with calcium supplementation [NIH ODS].
How it works
Think of calcium as a key structural material for your skeleton. It works through bone mineralization to support bone density and mineral deposition. It also plays a role in neuromuscular relaxation, helping your muscles relax and nerves signal properly [NIH ODS].
Safety profile
FDA received a total of 592,059 adverse event reports for this product type. Side effects from high calcium intake include 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 [FDA data] [NIH ODS]. Some research also suggests that high calcium intakes might increase the risk of heart disease and prostate cancer [NIH ODS].
Our recommendation
Be cautious with this supplement. Calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin. Do not exceed the recommended dose, and talk to your doctor about your total calcium intake from food and supplements to avoid high levels in your blood and urine [NIH ODS] [FDA data].
AI-assisted analysis. Data sourced from NIH DSLD.
Supplement Facts
| Brand | 21st Century |
|---|---|
| Serving Size | |
| Contents | 400.0 Caplet(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